Orals: Tue, 29 Apr | Room -2.15
In May 2024 the ESA/JAXA satellite mission EarthCARE was launched into a low Earth orbit. The satellite combines a high spectral resolution lidar and a cloud radar with doppler capability as key instruments on one single platform. Additionally, it is equipped with a multi spectral imager and a broad band radiometer. This unique combination makes EarthCARE the most complex single satellite mission to study aerosol, clouds and precipitation. The successful use of these new data for science application needs a thorough validation of the measurements and the derived data products. A similar EarthCARE-like payload was implemented onboard the German research aircraft HALO (High Altitude and Long range).
This instrumentation was flown during PERCUSION (Persistent EarthCARE underflight studies of the ITCZ and organized convection) campaign. Within its scientific component this field experiment aimed to test factors assumed to control the organization of deep maritime convection, and to investigate the influence of convective organization on the larger-scale environment. The validation part of PERCUSION focused on an as close as possible spatial and temporal co-location of the airborne with the space-borne measurement, which can only be done using an aircraft.
Thus, we included an EarthCARE underpass within each research flight. HALO measurements were performed during the EarthCARE commissioning phase in August 2024 out of Sal, Cape Verde, and out of Barbados in September 2024. In addition, we performed pure validation flights out of Oberpfaffenhofen, Germany in November 2024 for the validation under atmospheric conditions that could not be captured in the two first campaign parts. Altogether, 33 EarthCARE underpasses were performed in different aerosol and cloud situations. Some of the flights were coordinated with in-situ measurements onboard other aircraft (e.g. the French ATR42), with shipborne measurements onboard the German research vessel METEOR, or with ground-based radar and lidar measurements at Mindelo (Cape Verde), Barbados, and the ACTRIS stations Antikythera, Leipzig, Lindenberg and Munich.
In our presentation we will give a short overview of the HALO PERCUSION field experiment. Selected EarthCARE underpasses will be used to exemplify the merits and limitations of the level 1 and some level 2 data products of the ATLID lidar onboard EarthCARE.
How to cite: Wirth, M. and Groß, S.: Validation of EarthCARE lidar products using airborne measurements with the research aircraft HALO during the PERCUSION campaign, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3255, https://doi.org/10.5194/egusphere-egu25-3255, 2025.
Clouds exert multifaceted radiative effects on Earth's energy budget, serving as both insulators and reflectors of incoming solar radiation while also trapping outgoing infrared radiation. Consequently, clouds contribute to both surface cooling and warming processes, profoundly influencing regional and global climate dynamics. Despite their crucial role in Earth's energy balance, uncertainties persist regarding their feedback mechanisms.
A comprehensive understanding of clouds, including their spatial coverage, vertical distribution, and optical properties, is imperative for accurate climate prediction. Satellite-based observations, particularly those from active sounders, have offered continuous monitoring of clouds with high vertical and horizontal resolution since 2006. However, comparing cloud data from different spaceborne lidars presents challenges due to variations in wavelength, pulse energy, detector type, and local observation times.
This study discusses a methodology aimed at reconciling cloud data derived from several disparate spaceborne lidar platforms: CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation), which operated from 2006 to 2023; ALADIN/Aeolus (Atmospheric Laser Doppler Instrument), which operated from 2018 to 2023; IceSat-2, operational since 2018; and ATLID/EarthCARE (ATmospheric LIDar), launched last year.
For historical reasons, we use the Scattering Ratio at 532 nm (SR532) as a baseline for defining clouds across all lidars. The numerator contains the Attenuated Total Backscatter at 532 nm (ATB532), while the denominator includes a calculated Attenuated Molecular Backscatter at 532 nm (AMB532), assuming a cloud-free atmospheric profile. For measurements at other wavelengths, we convert the retrieved optical properties to SR532 and ATB532 to enable direct comparison. We demonstrate that this approach facilitates the retrieval of comparable cloud data for CALIOP and ALADIN using real measurements and for CALIOP and ATLID using synthetic measurements.
For lidars overlapping in time, the aforementioned cloud detection parameters can be fine-tuned to ensure a seamless transition between datasets. Collocated data are analyzed with respect to cloud fraction at different latitudes, altitudes, and seasons, and any differences are explored and corrected for, potentially accounting for instrument sensitivity or noise. However, when instruments do not overlap in time, an additional inter-calibrational procedure is necessary. We show how IceSat-2 can serve as a reference to align CALIOP and ATLID cloud datasets.
How to cite: Feofilov, A., Chepfer, H., Noël, V., and Dahuron, M.: Building a Long-Term Cloud Record from Spaceborne Lidars: Bridging CALIOP to ATLID, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12416, https://doi.org/10.5194/egusphere-egu25-12416, 2025.
The planetary boundary layer height (PBLH) is a critical atmospheric parameter influencing air quality, pollutant dispersion, and weather forecasting. Traditional methods for PBLH retrieval rely on radiosondes and ground-based sensors, but their spatial and temporal coverage is limited. In this study, we present a novel application of Random Forest (RF) machine learning to estimate PBLH using lidar measurements from the CALIPSO satellite's Level 1 data spanning a decade. Our RF model is trained with an extensive dataset of radiosonde-derived PBLH values coinciding with CALIPSO overpasses. This approach leverages CALIOP's lidar backscatter profiles to achieve robust performance (R² = 0.6, RMSE = 333.59 m) across a range of atmospheric conditions, including cloudy and dust-laden scenarios, without requiring atmospheric typing or ancillary data. The results surpass state-of-the-art methods in global applicability and accuracy, offering improved spatial and temporal resolution of PBLH estimates. We also discuss the model's performance variations between day- and nighttime scenarios and highlight challenges, such as data bias and surface reflection contamination, which inform future model refinements. This study underscores the potential of integrating machine learning and lidar remote sensing for advancing atmospheric science [1-2].
REFERENCES
[1] S. Lolli, W. Y. Khor, M. M. Z. Matjafri, and H. S. Lim, "Monsoon season quantitative assessment of biomass burning clear-sky aerosol radiative effect at surface by ground-based lidar observations in Pulau Pinang, Malaysia in 2014," Remote Sensing, vol. 11, no. 22, 2019.
[2] C. Sivaraman, S. McFarlane, E. Chapman, M. Jensen, Toto, S. Liu, and M. Fischer, Planetary Boundary Layer Height (PBL) Value Added Product (VAP): Radiosonde Retrievals, Tech. Rep., DOE Office of Science Atmospheric Radiation Measurement (ARM) Program, United States, Aug. 2013.
ACKNOWLEDGEMENTS
This research is part of the project PID2021-126436OB-C21 funded by Ministerio de Ciencia e Investigación (MCIN)/Agencia Estatal de Investigación (AEI)/ 10.13039/501100011033 y FEDER “Una manera de hacer Europa” and part of the PRIN 2022 PNRR, Project P20224AT3W funded by Ministero dell’Universit`a e della Ricerca. The European Commission collaborated under projects H2020 ATMO-ACCESS (GA-101008004) and H2020 ACTRIS-IMP (GA-871115).
How to cite: Rocadenbosch, F., Salcedo-Bosch, A., and Lolli, S.: Estimating Planetary Boundary Layer Height Using CALIPSO Lidar Data: A Machine Learning Approach, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19850, https://doi.org/10.5194/egusphere-egu25-19850, 2025.
The eVe lidar is ESA’s ground reference lidar system for the calibration and validation (cal/val) of ESA satellite missions. eVe is a combined linear/circular polarization lidar with Raman capabilities operating at 355 nm and deriving the profiles of the optical properties of aerosols and thin clouds, namely the particle backscatter and extinction coefficients, the lidar ratio, and the linear and circular depolarization ratios. The system is implemented in a dual-laser/dual-telescope configuration and it can be rotated to perform lidar measurements using different pointing geometries. As such, eVe can simultaneously reproduce the operation of any lidar system that uses linearly (e.g traditional polarization lidars; ATLID onboard EarthCARE mission) or circularly (e.g. ALADIN lidar onboard Aeolus mission) polarized emission.
The eVe lidar has been deployed in ASKOS, the ground-based component of the Joint Aeolus Tropical Atlantic Campaign in Cabo Verde (2021 and 2022), for performing targeted circular polarization lidar measurements for the validation of the Aeolus aerosol products (i.e. the Aeolus L2A products). The eVe-Aeolus comparisons reveal that the Aeolus co-polar backscatter coefficient is the most accurate L2A product followed by the noisier particle extinction coefficient with the larger discrepancies for the Aeolus profiles to be observed in lower altitudes where the aerosol load is larger. The Aeolus co-polar lidar ratio is the noisiest L2A product with the largest discrepancies from the corresponding eVe profiles. Currently the eVe lidar is under upgrade with main components of enabling the profiling of water vapor mixing ratio and extending the retrieval of the extinction coefficient towards daytime conditions, aiming to further enhance its measuring capabilities as well as to meet the requirements for the cal/val of the ATLID lidar products onboard EarthCARE mission which is currently in orbit. After the upgrade, eVe lidar will perform targeted measurements during the nearest EarthCARE overpasses from eVe’s location for the evaluation of the ATLID L2A products.
Acknowledgements:
This research is financially supported by the PANGEA4CalVal project (Grant Agreement 101079201) funded by the European Union 
and the “Best practice protocol for validation of Aerosol, Cloud, and Precipitation Profiles” ESA project (ACPV; Contract no. 4000140645/23/I-NS). The ASKOS campaign was funded by an ESA project (Contract no. 4000131861/20/NL/IA) and the acquired dataset can be accessed via https://evdc.esa.int/publications/askos-campaign-dataset/. The eVe lidar upgrade and the deployment for the cal/val of EarthCARE products are funded by an ESA project (Contract no. 4000146416/24/NL/FFi).
How to cite: Paschou, P., Marinou, E., Voudouri, K. A., Siomos, N., Gkikas, A., von Bismarck, J., Fehr, T., and Amiridis, V.: Using the ESA eVe reference lidar system for the cal/val of lidar instruments onboard ESA satellite missions, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17781, https://doi.org/10.5194/egusphere-egu25-17781, 2025.
Accurately measuring wind field is crucial for studying the dynamical structure and evolutionary characteristics of the atmosphere, as well as heat-momentum-matter exchange and balance. According to the World Meteorological Organization (WMO), global observation of the 3D wind field is the primary factor for improving the accuracy of numerical weather prediction. Due to the absence of aeronautical data, meteorological observation and forecasting capabilities are notably deficient in sparsely populated areas, the southern hemisphere, the polar regions, and the vast oceans. Spaceborne Doppler wind lidar has become an important instrument for observing the vertical profile of the global wind field, with the successful operation of Aeolus. The third generation of FengYun polar-orbiting meteorological satellites are initially designed to develop a dual-system Doppler wind measurement lidar technology programme that integrates direct and coherent detection lidar, making full use of the observational advantages of the two methods to detect the global wind field with high resolution. Incoherent detection is used in the middle and upper troposphere and lower stratosphere, where molecules scatter strongly. Coherent detection is used for the observation of the middle and lower troposphere and boundary layer. This research analyses the key parameters of the spaceborne hybrid wind lidar for future satellite missions. The incoherent detection module operates at 355 nm and uses the dual-edge detection technique based on Fabry?Pérot etalon. And the coherent detection module uses heterodyne detection technique operating at 1064 nm. This paper presents a simulation model for wind measurement lidar that realizes gridded atmospheric parameters, scanning observation, and forward-inversion simulation. And a method for detecting horizontal wind field based on dual-beam observation was developed to ensure the response of the lidar for wind speed detection in both meridional wind component and zonal wind component.
How to cite: Wu, S., Dai, G., Long, W., Sun, K., Zhai, X., Xu, N., and Hu, X.: Simulation and assessment of spaceborne hybrid Doppler wind lidar, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21151, https://doi.org/10.5194/egusphere-egu25-21151, 2025.
Atmospheric carbon dioxide (CO2) is the primary anthropogenic driver of climate change, accounting for more than half of the total effective radiative forcing (ERF). The accurate monitoring of carbon dioxide is essential to study the global carbon cycle and radiation budget on Earth.The Aerosol and Carbon Detection Lidar (ACDL) instrument, as the first space-borne integrated path differential absorption (IPDA) light detection and ranging (Lidar) for XCO2, was successfully launched in April 2022 onboard the DaQi-1 (DQ-1) satellite.During the two years of on-orbit operation, we constantly updated the processing methods, including the spectral broadening of CO2 caused by water vapor, etc. Finally, we calibrated and validated the CO2 retrieved by DQ-1 usingTCCON and COCOON, and the results showed that the deviation reached the satellite design demand (1ppm).
How to cite: Zhang, L. and Cao, X. C.: The calibration and validation of XCO2 measured by Lidar onboard DQ-1, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14705, https://doi.org/10.5194/egusphere-egu25-14705, 2025.
The Airborne Weather and Aerosol Lidar (A-WALI) is the first airborne meteorological lidar using Raman technology to measure the horizontal fields of water vapour, temperature, clouds and aerosols, as key weather and climate parameters (https://metclim-lidars.aeris-data.fr/). Based on lidar technologies tested in WALI (Totems et al., 2021; Chazette et al., 2014)) and ALiAS (Chazette et al., 2020), it was developed to meet the scientific objectives of ERC project MAESTRO (Mesoscale Organisation of Tropical Convection, https://maestro.aeris-data.fr). This experiment was motivated by the scarcity of observations of convective clouds organisation and their environment over the oceans, whereas this spatial organisation of mesoscale clouds, i.e. the tendency of convective clouds to aggregate and form clusters of varying horizontal and vertical extent, plays an important role in climate and meteorology. One of the objectives of the MAESTRO airborne campaign was therefore to sample the horizontal distribution of meteorological temperature and humidity fields, as well as the spatial distribution of aerosols and clouds. A-WALI was flown on board the ATR-42 aircraft of the SAFIRE unit (https://www.safire.fr/), departing from Sal in Cape Verde. The experiment, which took place between 10 August and 10 September 2024, was part of the international campaign ORCESTRA (Organised Convection Experiments in the Tropical Atlantic) supported by the World Climate Research Programme.
We will give examples of the measurements made by A-WALI and estimates of the associated uncertainties. We will discuss the calibration approach, the lidar sampling capabilities and limitations. Depending on the geophysical parameter under consideration, we will show at which spatial scales the lidar measurement provides relevant information and what its range can be.
How to cite: Cassan, H., Chazette, P., Totems, J., Laly, F., Lagarrigue, J., Guillet, V., Forges, L., and Bony, S.: An airborne Raman lidar to sample horizontal meteorological fields in the framework of MAESTRO, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3198, https://doi.org/10.5194/egusphere-egu25-3198, 2025.
Our understanding of the global carbon cycle needs for new observations of CO2 concentration at different space and time scales but also would benefit from observations of additional tracers of intra-atmospheric or surface-atmosphere exchanges to characterize sources and sinks. Lidar is a well-known promising technology for this research as it can provide, at the same time, structure of the atmosphere, dynamics and composition of several trace gas concentration. In this framework, a coherent differential absorption lidar (CDIAL) has been developed at LMD to measure simultaneously and separately 12CO2 and 13CO2 isotopic composition of CO2in the atmosphere. It also provides the wind speed along the line of sight of the laser with an additional Doppler ability. This paper investigates the methodology of three wavelengths DIAL in the spectral domain of 2-µm to obtain range-resolved CO2 isotopic ratio d13C. The set-up of the lidar as well as the signal processing is described in details. First atmospheric measurements along three days are achieved in the surface layer above the suburban area of Ecole Polytechnique campus, Palaiseau, France. Typical performances of the instrument (median values along 70h of measurement) with 10 min of time averaging show: (1) a precision around 0.6% for 1.2 km range resolution for 12CO2 mixing ratio (2) a precision around 3.2% for 1.6 km range resolution for 13CO2 mixing ratio. In situ co-located gas analyser measurements are used to correct for biases that are explained neither by the spectroscopic database accuracy nor the signal processing and will need further investigation. Nevertheless, this preliminary study enables to make a useful state of the art for current lidar ability to provide d13C measurements in the atmosphere with respect to geophysical expected anomalies and to predict the necessary performances of a future optimized instrument.
How to cite: Gibert, F., Edouart, D., Mondelain, D., Delahaye, T., Cénac, C., and Yver, C.: d13C carbon isotopic composition of CO2 in the atmosphere by Lidar, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12490, https://doi.org/10.5194/egusphere-egu25-12490, 2025.
Vibrational Raman lidar measurements of the water vapour mixing ratio (WVMR) were conducted during the WaLiNeAs (Water Vapor Lidar Network Assimilation) field campaigns in the western Mediterranean during autumn and winter 2022–2023 and in southwestern France (Toulouse) between June and September 2023. These campaigns, which spanned different seasons and geographical locations, provided an opportunity to sample various meteorological phenomena, including a dry winter, rainstorms, long-range aerosol transport, and an intense heat wave. Consequently, the water vapour content recorded in the lower troposphere showed significant variability during WaLiNeAs, ranging from less than 1 g kg-1 to more than 17 g kg-1. For operational purposes, a vertical resolution of 100 m and a temporal resolution between 15 and 60 min have been chosen. These resolutions are aligned with the spatio-temporal resolution of the ERA5 dataset from ECMWF's Integrated Forecasting System (IFS) global numerical weather prediction models. The processing of the lidar data has resulted in a scientific publication explaining the methods used to invert the lidar data and recover various atmospheric parameters. Lidar measurements address a critical gap left by operational instruments, which struggle to capture the diurnal cycle of water vapour from the planetary boundary layer to the lower free troposphere. The primary aim of this study is to compare ERA5 data with lidar-derived WVMR profiles. The results reveal altitude-dependent differences in Pearson correlation coefficient (COR), mean bias (MB), and root mean square deviation (RMSD), particularly during periods of high-water vapour content (> 10 g kg⁻¹). Over all periods the MB ranges from 0.1 to 3 g kg⁻¹, and the RMSD varies between 0.6 and 3.7 g kg⁻¹. COR ranges from 0.16 to 0.94, with lower values observed in the free troposphere during warmer periods. These variations underline the differences in the performance of the reanalysis model over different periods and altitudes when compared to lidar profiles. We show that the reanalysis constantly underestimated the WVMR at all altitudes. This study highlights the importance of scrutinising WVMR and the challenges faced by models during high water vapour meteorological events. The results provide valuable insights into the performance of operational numerical weather prediction models and highlight the need to refine their representation of WVMR vertical profiles in the lower troposphere by incorporating ground-based lidar measurements.
We give special thanks to the ANR grant #ANR-20-CE04-0001 for its contribution to the WaLiNeAs programme, to Meteo-France for its help with the measurements in Toulouse, and to the CNRS INSU national LEFE programme for its financial contribution to this project.
How to cite: Laly, F. and Chazette, P.: Raman lidar derived WVMR profiles compared to ERA5 - A WaLiNeAs application , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4141, https://doi.org/10.5194/egusphere-egu25-4141, 2025.
Water vapor information in the upper troposphere (UT) is crucial for understanding the thermodynamic conditions leading to the formation of cirrus clouds and persistent contrails. Both phenomena significantly contribute to aviation-induced radiative forcing, driving global mitigation efforts. Raman lidars provide high-resolution humidity profiles, describing altitudes prone to ice supersaturation—conditions that are challenging to detect and accurately represent in current models.
In this study, Raman lidar Water Vapor Mixing Ratio (WVMR) measurements from various sites in France were used to evaluate the performance of the ERA5 model in assessing humidity at typical aircraft altitudes. Additionally, the uncertainties in Microwave Limb Sounder (MLS) WVMR measurements at the same altitudes were assessed. Raman lidar profiles were aggregated into pseudo-monthly datasets to facilitate comparison with the limited number of MLS overpasses at each site, enabling validation of spatio-temporal pseudo-monthly lidar-matched MLS and ERA5 WVMR profiles.
The MLS dataset offers one of the longest records of WVMR, making it a valuable resource for trend assessment. This investigation enables the validated use of these datasets for studying UT humidity trends and variability on seasonal and annual scales over the past decade.
How to cite: Alraddawi, D., Keckhut, P., Mandija, F., Payen, G., Dupont, J. C., Pietras, C., Irbah, A., Sarkissian, A., Hauchecorne, A., and Porteneuve, J.: Raman lidar water vapor observations to assess the uncertainty of MLS and ERA5 at the upper troposhere, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10454, https://doi.org/10.5194/egusphere-egu25-10454, 2025.
Water vapour is a crucial and highly variable greenhouse gas in the Earth's atmosphere, which can significantly influence radiative balance, energy transport, and photochemical processes. It can also affect the radiative budget indirectly through cloud formation and by altering the size, shape, and chemical composition of aerosol particles. Accurate and systematic observations are essential for understanding its impacts and improving climate projections. Raman lidar technique is widely used for obtaining water vapour mixing ratio (WVMR) profiles with high vertical and temporal resolution. It relies on Raman scattering from water vapour and nitrogen molecules and is usually calibrated by reference to one or more external measurements of water vapour.
This study presents a hybrid methodology for obtaining high temporal resolution calibration constants for Raman lidar measurements, and posteriorly retrieves high accuracy WVMR profiles. It combines correlative measurements of precipitable water vapour (PWV) for calibrating lidar measurements with Numerical Weather Prediction (NWP) data to reconstruct the profile within the incomplete lidar overlap region. This methodology is applied to the MULHACEN Raman lidar system, operational at UGR station of the University of Granada (Spain) for the long period of 2009-2022. The hybrid method was optimized for the station by selecting Global Navigation Satellite System (GNSS) PWV data as the most appropriate due to its better agreement with correlative radiosondes (R2 of 0.95). Furthermore, the ERA5 model was selected as the most appropriate for reconstructing the incomplete lidar overlap region due to its better temporal and spatial resolution and its accuracy when evaluated against radiosonde data. The advantages of the hybrid calibration methodology are evaluated compared to traditional radiosonde-based methods or PWV data assuming a constant WVMR in the incomplete overlap region. Although all methods generally provide good calibration constants, the hybrid approach presented the best performance, as quantified by an R2 of 0.85, a slope of 0.97, and an intercept of -0.05 g/kg, particularly under conditions where atmospheric layers are not well-mixed. Comparison with radiosonde data revealed excellent agreement, with a mean bias error of -0.11 ± 0.38 g/kg and a standard deviation of 1.04 ± 0.35 g/kg across the entire period and vertical range (0 – 6.0 km agl). The most important result of this study is the ability to continuously evaluate calibration constants during 14 years of MULHACEN operation. The posterior application of the hybrid methodology to all MULHACEN measurements enabled the generation of a comprehensive long time database of WVMR profiles.
How to cite: Díaz Zurita, A., Pérez Ramírez, D., Neil Whiteman, D., Rodríguez Navarro, O., Bravo Aranda, J. A., Granados Muñoz, M. J., Guerrero Rascado, J. L., Abril Gago, J., Fernández Carvelo, S., del Águila Pérez, A., Antón Martínez, M., Vaquero Martínez, J., Haefele, A., Martucci, G., Foyo Moreno, I., Benavent Oltra, J. A., Alados Arboledas, L., and Navas Guzmán, F.: Calibration of water vapour Raman lidar using GNSS precipitable water vapour and reanalysis model data, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12573, https://doi.org/10.5194/egusphere-egu25-12573, 2025.
We present a Doppler lidar designed to detect the molecular spectrum characteristics, which are attributed to the Rayleigh-Brillouin scattering, in the atmospheric boundary layer. The suggested system is a continuous-wave, infrared Doppler lidar based on a bi-static transceiver and a coherent in-phase/quadrature detection scheme. For the detection of the features of the Rayleigh-Brillouin spectrum we use fiber-coupled, balanced photodetectors and a digitizer with a 1.6 GHz bandwidth. This broad bandwidth is necessary for the detection of Doppler shifts not only at frequencies of atmospheric winds, but also of the ones corresponding to molecular and acoustic speed that extend over several hundred megahertz. We demonstrate that using this configuration it is possible to detect the molecular Rayleigh-Brillouin spectrum over 30-minute time periods. The observational range of this system is focused on the lower part of the atmosphere (< 200 m) and the objective is to investigate if the resolved features of the Rayleigh-Brillouin spectrum can be related to the temperature, which could lead to the development of a novel vertical profiler of atmospheric temperature.
How to cite: Angelou, N. and Mann, J.: On the measurement of the Rayleigh-Brillouin spectrum and atmospheric temperature using a coherent Doppler lidar, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12657, https://doi.org/10.5194/egusphere-egu25-12657, 2025.
Wind is a core state variable of the atmosphere. Extending the capabilities of ground-based measurement systems, airborne Doppler lidar (ADL) onboard research aircraft allows for targeted and spatially resolved wind measurements, which are crucial for localized severe weather events or in inaccessible regions such as over water and complex terrain.
A novel ADL system – AIRflows (‘AIRborne fixed-beam lidar for wind measurements‘) – has been developed by the Karlsruhe Institute of Technology (KIT) in collaboration with scientific and industrial partners during the last two years.
Up to now, ADL systems use a single Doppler lidar attached to a scanner to provide radial velocity measurements under multiple viewing angles. Multiple viewing angles are needed to reconstruct the 3D wind from the unidirectional radial velocity measurements. Due to cost and size reductions of Doppler lidar units over the recent years, it has now become possible to construct an ADL system that uses multiple lidars with fixed-direction beams, instead of a single lidar with a scanning beam. The simultaneous availability of multiple viewing angles brings advantages: Simulation results have demonstrated that a multi-lidar system can achieve approximately one order of magnitude improved spatial wind measurement resolution as well as higher accuracy, compared to existing scanning systems.
This contribution presents the novel AIRflows system developed by KIT. AIRflows implements the novel fixed-beam, multi-lidar concept onboard the TU Braunschweig Cessna F406 research aircraft. The system uses five modified Doppler lidar modules manufactured by Abacus Laser, one pointing nadir and the other four pointing forward, aft, left and right at an elevation of 30° from nadir.
The first flights deploying AIRflows have been successfully completed during summer 2024. Initial analysis demonstrates wind profiles at 100 m spatial resolution, allowing to resolve fine-scale 3D winds inside the PBL for the first time. As part of the tests, flights to the Alps were conducted in preparation for the upcoming international TEAMx campaign. AIRflows measurements across Alpine valleys and crests provide previously unattainable insight into vertical wind and valley circulations in complex terrain. Similarly, AIRflows measurements across a wind farm in the North Sea provide novel vertically resolved insight into wind farm wake behavior.
Overall, AIRflows revolutionizes the field of airborne wind measurements by providing an order of magnitude improved spatial resolution as well as higher measurement accuracy, compared to previously existing ADL.
How to cite: Gasch, P., Wieser, A., Feuerle, T., Winter, F., and Bollig, C.: AIRflows - a novel airborne Doppler lidar for high resolution wind measurements, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15290, https://doi.org/10.5194/egusphere-egu25-15290, 2025.
Over the last 30 years, the demand for wind profile observations in the lower troposphere has rocketed, carried by weather agencies, airports and the wind energy industry. Doppler lidars are favoured for their compactness, easiness of operation, and versatility in the scanning strategy. Several methods have been developed to reconstruct the horizontal wind profile from the raw radial wind observations recorded in different directions. The most common is the Doppler Beam Swinging (DBS) technique, which is implemented in commercial lidars software. However, DBS leaves a blind zone near the ground that can damper the observation of very low-altitude phenomena like certain low-level jets.
Another horizontal wind reconstruction method consists in combining observations from two vertical sweeps of the Range-Height Indicator (RHI) type recorded in perpendicular directions, by binning the data into horizontal layers. To our knowledge, this cross-RHI technique has only been used twice [1, 2] and applied to only a few tenth of hours of lidar scans, so that this method still needs to be fully validated over a longer period and under more varied conditions.
In this study, the cross-RHI and DBS techniques were compared using observations recorded by two Doppler scanning lidars from the Leosphere/Vaisala company, installed at two contrasting sites in France: a flat coastal site (Dunkerque, North Sea coast) for four months, and an urban hilly site (Paris) for two months. Compared to the previous studies and to the DBS method, the cross-RHI technique was improved by adding filtering steps designed to remove range-folded echoes from middle-level clouds. In addition, the flow inclination on the hilly site was taken into account by tilting the wind binning layers and minimizing the total intra-layer variance.
The horizontal wind speed values retrieved using both techniques were in very good agreement on both sites, with correlation coefficients ~0.92 in the first 200 m above the lidar. The regression slope was 0.93 and the intercept was below 0.4 m/s on both sites, drawn by a small share of points where the DBS grossly overestimated the wind speed due to range-folded echoes. This problem disappeared at higher altitudes, where the correlation coefficients exceeded 0.97, with slopes ~0.97 and intercepts lower than 0.1 m/s. In Dunkerque, where the DBS were averaged over 10 consecutive cycles, the horizontal wind direction difference was smaller than 5° (resp. 10°) for 61% (resp. 83%) of observations in the first 200 m above the lidar, and these numbers also improved with increasing altitude. Additionally, the cross-RHI technique proved to be more efficient to reconstruct the wind in pristine conditions yielding low lidar signal.
This method’s ability to capture very low-altitude phenomena while providing turbulence information opens new perspectives for urban studies and wind farm site assessment.
References
[1] R. M. Banta et al., “Nocturnal Low-Level Jet Characteristics Over Kansas During Cases-99,” Bound.-Lay. Meteorol., 105(2), 221–252, 2002, doi: 10.1023/A:1019992330866.
[2] T. A. Bonin et al., “Evaluation of turbulence measurement techniques from a single Doppler lidar,” Atmos. Meas. Tech., 10(8), 3021–3039, 2017, doi: 10.5194/amt-10-3021-2017.
How to cite: Dieudonné, E., Haezebrouck, P., Maynard, P., Sokolov, A., Delbarre, H., Augustin, P., and Fourmentin, M.: Horizontal wind profiling with Doppler lidars: long-term evaluation of the perpendicular vertical sweeps reconstruction method, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3463, https://doi.org/10.5194/egusphere-egu25-3463, 2025.
Windstorm, particularly driven by thunderstorms, are among the most destructive natural hazards in Europe causing significant economic losses and causalities. Despite various research, the understanding of thunderstorm outflows and their interaction with built and natural environments remains incomplete, especially in regions prone to intense convective activity, such as the northern Italy. This study focuses on the three-dimensional (3D) structure and dynamics of thunderstorm clouds, emphasizing the formation of downburst and gust fronts that generates damaging surface winds. To construct the 3D wind structure, dual Doppler radar systems are utilized, combining data from operational C-band radar and X-Band radar within the study area. A LiDAR instrument was also operational during the investigated event; however, the scanning LiDAR and C-band radar volume do not overlap due to sheltered positioning of the LiDAR relative to the radar. The inclusion of the X-band radar resolves this issue by covering areas that are blind to C-band radar, thereby re-establishing continuity in measurements across the three instruments. This configuration ensures continuous and comprehensive spatial coverage of wind field measurements, spanning from surface to maximum observation altitude. To carry this out, historical thunderstorm events that occurred in the Piedmont region, Italy, in 2024 are analysed to enhance present understanding of convective dynamics, and the development of severe wind phenomena. This research will also help identify patterns associated with gust fronts and downbursts, hence facilitating improved nowcasting and risk mitigation strategies for these localized windstorms.
How to cite: Kumari, P., Burlando, M., Bechini, R., Romanic, D., and Battaglia, A.: 3D Wind Field Retrieval within Thunderstorm Clouds over Piedmont, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2855, https://doi.org/10.5194/egusphere-egu25-2855, 2025.
E-Profile is the EUMETNET Programme coordinating the measurements of vertical profiles of wind, aerosols and clouds from radars and lidars in Europe. The E-Profile wind network provides near real-time vertical profiles of wind from weather radars and dedicated wind profilers with the main goal to promote the usability of these data for operational meteorology and provide expertise to both the data provider and the end-user.
Ground-based scanning Doppler Wind Lidars (DWLs) are capable of measuring wind profiles in the atmospheric boundary layer (ABL) at a high spatial and temporal resolution and they have the potential to improve the short-term wind forecast. With the availability of commercial DWLs in the last decade, many meteorological services and scientific institutions are now operating such instruments or are planning to do so in the future in Europe.
To extend the benefit of these observations and promote data sharing, these instruments have recently been integrated in E-Profile wind profiling network. Using an open-source code developed at the Deutscher Wetterdienst (DWD), instrument’s data from different manufacturers are processed in a harmonized way to provide 10 minutes averaged wind profiles in the ABL. Data are converted to BUFR and distributed in near real-time on the Global Telecommunication System (GTS), making them available globally for data assimilation. At the moment, 12 DWLs from 4 European countries are being processed operationally and more instruments are expected to join the network in 2025.
Here, we present the integration of DWL into the E-Profile wind network, its associated challenges and the requirements for the scan strategies. We also show comparisons at different sites against other wind profiling instruments (e.g. radar wind profilers) and against model data. Finally, we also discuss the future improvements to the network.
How to cite: Sauvageat, E., Rüfenacht, R., Hervo, M., Turp, M., Kayser, M., Leinweber, R., Lehmann, V., Knoop, S., Gohm, A., and Haefele, A.: Integration of Doppler Wind Lidars in E-Profile wind profiling network, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16832, https://doi.org/10.5194/egusphere-egu25-16832, 2025.
Scanning Doppler Wind Lidars are used in a variety of applications, thanks to the versatility brought by their scanning head. Their principal output is the wind speed along the lidar beam, termed the radial wind speed. When used for vertical profiling, the horizontal wind speed and wind direction are obtained from a wind field reconstruction algorithm (DBS or VAD) applied to the radial wind speed along several high-elevation lines of sight.
However, for other scanning strategies (i.e., with low elevation or horizontal scans), the use of such algorithms is not common, making the radial wind speed the sole output of the Doppler Wind Lidar. The radial wind speed is more difficult to interpret visually for a human user, harder to compare with numerical models, and requires more work to be used into advanced algorithms.
Thus, we showcase the Volume Wind wind field reconstruction algorithm, capable of reconstructing the horizontal wind speed and wind direction from measurement points taken at the same elevation and varying azimuth.
We present data taken from the PANAME2022 campaign, in which a Doppler Wind Lidar (WindCube Scan 400S) was set up on an 88m-high tower in Paris city. The lidar performs scans at 0° elevation above the urban area of Paris, measuring radial wind speed from within the Urban Boundary Layer. Then, we create maps of horizontal wind speed and direction, spanning a large part of the Paris urban area, using the Volume Wind wind field reconstruction algorithm.
This allows us to study the influence of the topography on the wind field at the height of the urban canopy. The effect of the bed of the Seine river is of particular interest, as it is thought to be an important ventilation corridor in periods of extreme heat. These results highlight the potential of remote sensors for studying the Urban Boundary Layer, and the added value of advanced processing algorithms.
How to cite: Toupoint, C., Cespedes, J., Kotthaus, S., Thobois, L., Haeffelin, M., and Preissler, J.: Mapping horizontal wind speed using a single Doppler Wind Lidar scanning horizontally: a test case over Paris, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1212, https://doi.org/10.5194/egusphere-egu25-1212, 2025.
The upper atmosphere located at an altitude of 80 - 120 km above the ground is a crucial region for comprehensively understanding the behavior of Earth's entire atmosphere, because it is the region where the atmosphere transitions from neutral to ionospheric. In this transitional region, meteoroids are continually supplying metallic atoms and ions. The resonant-scattering lidar, which emits laser beams from the ground and then detect on the ground again how much atoms and ions cause resonant scattering of the laser radiations, is one of the significant measurement methods of observing such transitional region. While Fe and Na are selected as the major targets, we have focused on Ca and have developed a specific lidar system to detect it. This is because Ca has uniquely preferable resonance transitions for neutral atoms and ions (Ca: 422.7918 nm and Ca+: 393.4770 nm) for performing lidar measurements from the ground. The core of the developed resonant-scattering Ca/Ca+ lidar system is the injection-locked Ti:sapphire solid-state laser, which has the remarkable ability to simultaneously emit the two laser beams from a single resonator at a variety of combinations of two wavelengths, including the above resonant transitions of neutral Ca and Ca+.
Here, we report on the first results of the long-term observations, where the developed resonant-scattering Ca/Ca+ lidar system was operated for an entire night. The averaged laser power, time resolution, and altitude resolution of the Ca/Ca+ lidar system are set to 0.2 W, 30 s, and 15 m, respectively, for Ca, and 0.4 W, 30 s, and 30 m , respectively, for Ca+ in this operation. Both neutral Ca and Ca ions distributed in the identical spatio-temporal regions could be measured in detail over an entire night. It was clearly observed that the neutral Ca and Ca ions had almost the same spatio-temporal structures with complex time and space dependences in the main layer at an altitude of 80 - 100 km, and Ca ions also had an additional high-density thin layer with a few kilometers deep at the highest altitude in the main layer. This high-density layer of Ca ions, which was not seen with the neutral Ca, suggests that it is to be related to the sporadic E layer. In our presentation, we will also report on the progress of this ongoing project.
How to cite: Katsuragawa, M., Ejiri, M. K., Hashimoto, A., Kobayashi, S., Miyoshi, S., Miyagi, H., Ohae, C., and Nakamura3, T.: Simultaneous observations of meteoric Ca and Ca+ by employing the Ti:sapphire-laser-based resonance-scattering Ca/Ca+ lidar, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21736, https://doi.org/10.5194/egusphere-egu25-21736, 2025.
Atmospheric lidar has become a powerful tool for atmospheric detection due to its advantages of high spatiotemporal resolution, multiple parameters and high-precision detection. In this paper, the application status of lidar in China’s meteorological observation is introduced, and the prospects for the development of lidar applications are presented. For better observation of atmospheric clouds, aerosol, and water vapor parameters, the China Meteorological Administration(CMA) has laid out and constructed a Raman-Mie aerosol lidar network with 49 stations from 2021 to 2024 and has solved several key technical problems such as data quality control, parameter inversion, and quantitative calibration. In order to achieve high-precision observations with a time resolution at the minute level, more than 10 standard specifications have been formulated for calibration, observation, and data transmission. The lidars for network applications normally use a three-wavelength laser covering 355 nm, 532 nm, and 1064 nm,and they can achieve a detection distance of more than 10 km, an accuracy of aerosol backscattering coefficient of less than 20%（0.5-2 km）and 40%（2-5 km）, and an accuracy of water vapor concentration of less than 1g/kg (0.5-3 km).In the field of wind observation, the CMA has laid out and constructed a wind lidar network with 372 stations by 2024. The lidars use the coherent detection with a laser wavelenth of 1550nm, and they can achieve a maximum detection distance of more than 3km, a horizontal wind speed error less than 0.8m/s, and a horizontal wind direction error less than 8°.The layout and application of aerosol lidar network and wind lidar network have greatly improved China's meteorological observation capability and application levels in aerosol and wind fields. In recent years, the CMA has actively cooperated with various universities and scientific research institutes to carry out key technological studies in atmospheric temperature and humidity lidar, high spectral resolution lidar, middle and upper atmosphere lidar, and airborne/spaceborne lidar. Through planning and constructing meteorological business application platforms in the future, the comprehensive three-dimensional observation of multiple parameters such as temperature, humidity, wind and aerosols will be developed to improve China's meteorological observation ability and provide strong support for research in meteorological services, atmospheric science and climate change.
How to cite: Chen, Y.: Status and Development of Lidar applications in China's Meteorological Observation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5725, https://doi.org/10.5194/egusphere-egu25-5725, 2025.
A rise of approximately 1°C in global average temperature is influencing sea surface temperature, sea-level, intensity of storms, frequency and severity of hydro-meteorological extreme events. Such effects are comparatively more pronounced in tropical and sub-tropical zones, wherein Leh-Ladakh region of Indian subcontinent, is peculiar and characterized by extreme weather conditions. The present work unravels the cloud characteristics over the Leh region using ground-based ceilometer lidar (3255 m above mean sea level), remote-sensing, and reanalysis data sets for one-year (September 2022–August 2023). Variations in cloud base height (CBH) was observed with lidar, enabling the measurement of CBH up to three distinct layers, designated as CBH1, CBH2, and CBH3, respectively. This study reveals distinct seasonal and altitudinal variations in CBH, with cloud occurrence frequencies peaking during the pre-monsoon (67.94%) and monsoon (98%) seasons, reflecting the onset and active phases of the Indian summer monsoon. Month of July was recorded with the highest prevalence of multi-layered clouds (84.03%), which includes triple-layered clouds (CBH3, 42.13%) dominating over double-layered (CBH2, 25.98%) and single-layered (CBH1, 15.92%) clouds. Seasonal analysis showed a dominance of mid-level clouds (~3–6 km, 77.53%), while high-level clouds (~6–18 km, 4.43%) were less frequent. Altostratus and altocumulus clouds were particularly prominent across all seasons, with their variability linked to topographic and climatic factors. The ceilometer's high-resolution measurements captured the temporal dynamics of CBH, which aligned with satellite and reanalysis data, demonstrating the value of ground-based instruments in complementing remote sensing technologies. These findings provide valuable insights into cloud dynamics and their role in extreme weather events such as cloudbursts and intense rainfall, which are increasingly frequent in the Himalayan region. By improving our understanding of cloud–precipitation interactions, this study offers critical information for enhancing weather forecasting, informing rainfall prediction models, and supporting climate adaptation strategies in climatically vulnerable high-altitude regions.
How to cite: Shah, R., Sharma, S., Kamat, D., Ningombam, S., Angchuk, D., and Srivastava, R.: Comprehensive Study of Cloud Characteristics over a High Altitude Station - Leh, India using Ground-Based Lidar and Satellite Observations, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16068, https://doi.org/10.5194/egusphere-egu25-16068, 2025.
In recent years, there has been an increase in the intensity and frequency of smoke plume events over North America (sometimes reaching Europe) and dust plume events reaching Europe from Africa. As these can potentially affect surface air quality, environmental agencies are increasingly interested in being able to identify the nature of aerosol plumes, monitor it in real time and determine whether its interaction with the atmospheric boundary layer will impact surface air quality. The automatic LIDAR-ceilometer (ALC) primarily designed for cloud base height detection has greatly improved over the last years and now provides vertical profiles of backscatter from aerosols and clouds. Recently, a new type of ALC with a depolarization function (VAISALA CL61) is commercially available for distinguishing cloud phase (which is useful for weather forecasting) and also makes it possible to support the type identification of aerosols.
At the Royal Meteorological Institute of Belgium (RMI), we have been developing a new pioneering algorithm (CONIOPOL: CONIOlogy + POLarization) based only on CL61 measurements (backscatter and depolarization profiles) to provide in real-time automatic identification of cloud phase, precipitation type and aerosol type. CONIOPOL cannot provide an independent and unambiguous identification of the aerosol type because the CL61 operates with a single wavelength. Although, CONIOPOL is a very useful operational support allowing a quick identification in real time of the type of aerosols in combination with forecasts and backward trajectories models.
The effectiveness and robustness of CONIOPOL will be demonstrated in different ways, through case studies comparing its output with CAMS forecast and air quality measurements, through statistical analysis of CONIOPOL output and by a comparison analysis between CONIOPOL output and CAMS forecasts. In addition to its operational use, it is capable of assembling a climatology of cloud phase, precipitation type and aerosol type. Further, it can contribute to the validation of EarthCARE (ESA) space-borne products.
How to cite: Laffineur, Q., Mangold, A., De Causmaecker, K., and Delcloo, A.: New operational perspective to identify aerosol in real-time with a pioneering algorithm (CONIOPOL) based on CL61 data, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8390, https://doi.org/10.5194/egusphere-egu25-8390, 2025.
In recent years, several climate and air quality applications have required to understand the impact of aerosols close to their source, leading to the development of novel Short-Range Elastic Backscatter Lidars (SR-EBLs), which enable measuring the radiative properties of aerosols at high spatiotemporal resolutions (<10cm, 1s) in the short-range (3 to 500m). However, the elastic lidar equation is an ill-posed problem, having one equation for two atmospheric variables: the backscatter β(r) and extinction α(r) coefficients. Solving this equation requires assuming a value for the lidar ratio, i.e., a linear relationship between β and α, reducing the accuracy of the retrievals. Advanced lidar techniques, like the High Spectral Resolution Lidar (HSRL), measure molecular and particle scattering separately. Having a direct measurement of the molecular component allows for solving the lidar problem without assumptions about the lidar ratio. However, the existing atmospheric HSRLs cannot perform short-range measurements because i) they are usually blind in the first hundredths of meters (overlap restrictions), and ii) they prioritize spectral performance using ultranarrow band (and thus long-pulse) lasers, resulting in an insufficient spatiotemporal resolution.
This work presents a proof-of-concept of a Short-Range High Spectral Resolution Lidar (SR-HSRL) optimized for aerosol characterization in the first kilometer of the atmosphere. This SR-HSRL uses a compact high-repetition rate fiber laser source with a 300 MHz linewidth and 5 ns pulse length. Since these two parameters are inversely proportional, and both are required for performing SR-HSRL measurements, a compromise had to be found to optimize the overall performance. The main challenge was to prove that, despite its relatively large linewidth, this laser has a satisfactory spectral performance so that it can be used for future implementations of the short-range HSRL. We chose this model after evaluating several laser sources because it has the right compromise between pulse length, linewidth, spectral stability, and size. The laser housing is 270 x 270 x 40 mm and weighs 2.9 kg, making it ideal for future integration on a portable short-range HSRL system.
In the receiver part, a 10:90 beam splitter transmits 10% of the backscattered light to the total channel and reflects 90% of it to the HSR channel. A 40-cm-long iodine cell is used as the spectral filter for separating the Mie and Rayleigh aerosol components. We used two thermoelectrically cooled SiPM Multi-Pixel Photon Counter (MPPC) sensors and a 160MHz analog-to-digital converter to measure the signals. The spatiotemporal resolution, limited by the acquisition system, is 7.5 m and 1 s.
To test the lidar, a two-day measurement campaign was performed at NIES in Tsukuba, Japan, in July 2024. We demonstrate that, despite having a relatively large laser linewidth, we can successfully remove the Mie aerosol component, retrieving aerosol backscatter coefficient profiles from as low as 80 m. We also compare the HSRL retrieval method to a non-conventional forward Fernald inversion method previously reported for SR-EBL. We found that the forward method normally sub-estimates β (up to 30% discrepancy) in aerosol layers and overestimates it in cloud zones (60 to >100% difference).
How to cite: Hoyos Restrepo, M., Ceolato, R., and Jin, Y.: Proof-of-Concept of a Short-Range High Spectral Resolution Lidar using a Compact High Repetition Rate Fiber Laser, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20478, https://doi.org/10.5194/egusphere-egu25-20478, 2025.
Atmospheric remote sensing from space and surface has been advanced during the last decade. Mineral dust is an atmospheric target that provides a strong signature on active and passive polarimetric remote sensing observations, due to its irregular shape. Nowadays, advanced lidar systems operating in the framework of ACTRIS provide quality assured, calibrated multi-wavelength linear particle depolarization ratio measurements, while new developments will provide us elliptical polarization recordings in the near future. Passive polarimeters are already part of ACTRIS and AERONET and their integration in operational algorithms is expected in the near future. This wealth of new information combined with updated scattering databases and sophisticated inversion schemes provide the means towards an improved characterization of desert dust in the future. This kind of information can be used for space-borne lidars such as CALIPSO, CATS, Aeolus, EarthCARE and the future AOS missions.
We present here some examples of how remote sensing facilitates desert dust research during the last decade, aiming to demonstrate the progress on issues such as: (a) the discrimination of desert dust in external mixtures, (b) the estimation of the fine and coarse particle modes, (c) the synergy of passive and active remote sensing for the derivation of dust properties, (d) the provision of dust-related CCN and IN particle concentrations for aerosol-cloud interaction studies, (e) the development of new scattering databases based on realistic particle shapes, (e) the application of these techniques on space lidar datasets for the provision of climatological datasets, and (f) the use of these datasets in data assimilation for improving dust representations in models.
How to cite: Amiridis, V.: Desert dust profiling and applications, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6889, https://doi.org/10.5194/egusphere-egu25-6889, 2025.
This study presents a detailed analysis of the optical and microphysical properties of biomass burning aerosols from two distinct smoke plumes observed on 16 July 2024 at the CIAO atmospheric observatory in Potenza, Italy. The lower layer corresponds to a local wildfire, while the upper layer correspond to a long-range transported plume from Canada. The objective is to highlight significant differences in their characteristics and atmospheric impacts.
The local fire was characterized not only with lidar measurements, but with all the remote sensing instruments present in the observatory. The fire, ignited around 16:00 UTC approximately 2 km from the observatory, was detected within an hour. Ceilometer lidar and radar data showed that wildfire particles ascended to 3 km, where elevated humidity facilitated the formation of condensation nuclei, confirmed by a radiometer-observed peak in liquid water content. The ACSM (Aerosol Chemical Speciation Monitor) and aethalometer measurements show a significant peak around 20:00 UTC, which coincides with the deposition of the particles. The inversion results from lidar measurements revealed a low contribution of black carbon and fine-mode particles, consistent with incomplete combustion typical of small-scale fires. Furthermore, a strong dependence on humidity variations was observed, emphasizing the dynamic interaction between local fires and atmospheric conditions.
In contrast, the Canadian wildfire plume, transported at altitudes between 5.5 and 6.5 km, exhibited different characteristics. Due the complete combustion particles have a higher absorption properties. The lidar ratio at 532 nm exceeded that at 355 nm, similar with previous observations of aged wildfire plumes. During long-range transport, aging processes such as coagulation significantly altered the particles, increasing their effective radius. Microphysical analysis indicated the presence of larger, more absorbent particles compared to the local plume.
This study underscores the importance of integrating remote sensing and in-situ measurements to capture the lifecycle of wildfire events. The results reveal a great variability in smoke plume properties, which must be accounted for in radiative transfer models to accurately assess their atmospheric and climatic impacts.
How to cite: De Rosa, B., Papagiannopoulos, N., Mytilinaios, M., Amodeo, A., D'Amico, G., Rosoldi, M., Summa, D., Gandolfi, I., Papanikolaou, C., Gumà-Claramunt, P., Laurita, T., Cardellicchio, F., Veselovskii, I., Di Girolamo, P., and Mona, L.: Comparison of fresh and aged smoke particles simultaneously observed at the ACTRIS Potenza observatory , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10120, https://doi.org/10.5194/egusphere-egu25-10120, 2025.
Cirrus clouds play a critical role in Earth's radiation budget and are key to understanding and forecasting climate adaptation in response to global warming. Leveraging 20 years of high-resolution lidar data from NASA's MPLNET network, we analyze and forecast cirrus cloud radiative forcing with the aim of projecting how the climate system will adapt to changing atmospheric conditions. Using ensemble learning methods, we simulate the monthly radiative impacts of cirrus clouds, emphasizing their variability and feedback mechanisms. The study also integrates future climate scenarios under shared socio-economic pathways ( CMIP6SSP2-4.5 and SSP5-8.5) to explore potential shifts in regional climate patterns driven by cirrus cloud interactions. Results highlight how increased temperatures and altered precipitation regimes may influence the climate's adaptive processes, particularly in regions currently sensitive to radiative forcing fluctuations. This research underscores the importance of long-term lidar data for advancing climate adaptation modeling and identifying critical atmospheric feedbacks.
[1] Lolli, S., 2023. Machine Learning Techniques for Vertical Lidar-Based Detection, Characterization, and Classification of Aerosols and Clouds: A Comprehensive Survey. Remote Sensing, 15(17), p.4318.
How to cite: Lolli, S., Salcedo-Bosch, A., Lewis, J. R., Dolinar, E. K., Campbell, J. R., and Welton, E. J.: Forecasting Climate Adaptation Through Cirrus Cloud Radiative Forcing Analysis Using 20 Years of MPLNET Lidar Measurements, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19403, https://doi.org/10.5194/egusphere-egu25-19403, 2025.
Cirrus clouds cover about 30% of the Earth’s surface and play a crucial role in the Earth’s radiation balance. They are composed of ice crystals with various sizes and nonspherical shapes. Ice crystals can form through either homogeneous freezing or heterogeneous freezing depending on the ambient temperature, humidity, updraft, and the availability of INPs, and hence possess different properties. Their radiative effects strongly depend on the formation processes and cloud microphysical, thermal, and optical properties. Furthermore, global aviation affects the Earth’s radiation balance by increasing cloudiness due to contrail formation and exerting an indirect effect on the microphysical properties of naturally-formed cirrus clouds. Aviation is responsible for 3-4% of anthropogenic effective radiative forcing and more than half of them stems from contrails and contrail-induced cirrus. Experimental and numerical studies have been carried out in the past years to understand contrails and contrail-induced cirrus as well as their climate effects. Unfortunately, however, the parameterization of ice crystal properties in global climate model and the estimate of radiation forcings are still inadequate. Compared with the intensive studies on cirrus clouds in the tropics and midlatitude regions, cirrus cloud measurements and model studies at high latitudes are sparse, although cirrus clouds at high latitudes attract more attention in recent years because the Arctic undergoes faster warming than other regions of the globe. The airborne measurements from the ML-CIRRUS mission revealed that cirrus clouds with enhanced PLDR appear in areas of high aviation emissions. Nevertheless, observational evidence of indirect effects of aviation exhaust on the changes of cirrus properties is still missing. Thanks to the foundational work of ML-CIRRUS, the CIRRUS-HL mission in June-July, 2021, with upgraded instrumentation was designed to characterize cirrus cloud at both high- and midlatitudes and to investigate aviation impact, radiation, and aerosol-cloud interactions. It collected more details in the simultaneous profiling of cirrus cloud and aerosol properties. In this study, we focus on the comparison of particle linear depolarization ratios (PLDR) of cirrus clouds with the airborne lidar WALES from two specific flights under similar cloud formation processes during CIRRUS-HL. Their microphysical properties (i.e. ice crystal size and number concentration) are also determined and compared based on the analysis of simultaneous in-situ measurements. The analysis is also extended to all the flights for statistical results. Furthermore, the characterization of aerosol load, especially aviation soot, will be identified in the regions of ice crystal formation and evolution and their correlations with cirrus cloud properties are finally able to be further determined.
How to cite: Li, Q., Gross, S., Wirth, M., Jurkat-Witschas, T., Voigt, C., De La Torre Castro, E., and Sauer, D.: Aerosol impacts on cirrus cloud formation and properties using in-situ and lidar measurements during CIRRUS-HL campaign , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5758, https://doi.org/10.5194/egusphere-egu25-5758, 2025.
The orientation of ice crystals plays a significant role in determining their radiative and precipitating effects, horizontally oriented ice crystals (HOICs) reflect up to ~40 % more short-wave radiation back to space than randomly oriented ice crystals (ROICs). This study for the first time introduces an automatic pixel-by-pixel algorithm for HOIC identification using a combination of ground-based zenith- and 15-degree off-zenith-pointing polarization lidars. The lidar observations provided high-resolution cloud phase information. The data were collected in Beijing over 354 days in 2022. A case study from 13 October 2022 is presented to demonstrate the effectiveness and feasibility of the detection method. The synergy of lidars and collocated Ka-band cloud radar, radiosonde, and ERA5 data provide phenomenological insights into HOIC events. While cloud radar Doppler velocity data allowed the estimation of ice crystal size, Reynolds numbers, and turbulent eddy dissipation rates, corresponding environmental and radar-detected variables are also provided. HOICs were present accompanying with weak horizontal wind of 0–20 ms−1 and relatively high temperature between −8 °C to −22 °C. Compared to the ROICs, HOICs exhibited larger reflectivity, spectral width, turbulent eddy dissipation rate, and a median Doppler velocity of about 0.8 ms−1. Ice crystal diameter (1029 µm to 1756 µm for 5th and 95th percentiles) and Reynolds numbers (28 to 88 for 5th and 95th percentiles) are also estimated with the help of cloud radar Doppler velocity using an aerodynamic model. One interesting finding is that the previously found switch-off region of the specular reflection in the region of cloud base shows a higher turbulence eddy dissipation rate, probably caused by the latent heat released due to the sublimation of ice crystals in cloud-base region. The newly derived properties of HOICs have the potential to aid to derive the likelihood of their occurrence in output from general circulation models (GCMs) of the atmosphere.
How to cite: Wu, Z., Seifert, P., He, Y., Baars, H., Li, H., Jimenez, C., Li, C., and Ansmann, A.: Assessment of horizontally-oriented ice crystals with a combination of multiangle polarization lidar and cloud Doppler radar, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18284, https://doi.org/10.5194/egusphere-egu25-18284, 2025.
Lidar is an essential and unique tool in the current integrated spaceborne remote sensing observation system. From CALIPSO-CloudSat in the A-Train constellation to China’s Daqi-1 (DQ-1) and the latest EarthCARE mission, lidar’s ability to detect thin cirrus and low clouds with fine vertical resolution has significant implications. The effective combination of lidar and CPR provides a complete cloud vertical structure for related studies and an accurate validation for passive remote sensors.
Launched successfully on April 16, 2022, the DQ-1 satellite carries the Aerosol Carbon Detection Lidar (ACDL), a three-wavelength (532, 1064, and 1572 nm) lidar for comprehensive measurements of atmosphere composition. is technically a combination of two lidars with different mechanisms: a high-spectral-resolution lidar (HSRL) measuring clouds and aerosols and an integrated-path differential absorption (IPDA) lidar measuring carbon dioxide. The mechanism of HSRL allows the separation of aerosol contribution from the molecular backscatter, therefore removing the lidar ratio assumption in the traditional Mie-scattering lidar like CALIOP. Initial validation results indicate an accuracy better than 20% for a strong signal backscatter profile with 24 m vertical resolution. The cloud-top and base height, phase, and classification products have been processed accordingly.
Positioned time-wise between CALIPSO and EarthCARE missions, DQ-1 fills a critical gap in the observation and cross-validation. This report contains results from a one-year-long comparison between DQ-1/ACDL and CALIPSO/CALIOP from June 2022 to June 2023, till the end of CALIPSO operation. The analysis includes case studies from different latitudes and scenarios, and overall gridded global thin cirrus cloud distributions. The results show good consistency between the two systems, with DQ-1/ACDL demonstrating better coherence and performance. Depending on data availability, the report might also include preliminary comparisons with EarthCARE/ATLID data. The report will highlight key improvements of the DQ-1/ACDL system in thin cirrus cloud detection, for better monitoring and valuable insights of cloud properties, atmospheric dynamics, and climate modeling.
How to cite: Chen, S., Li, B., and Zhang, K.: Improvement of DQ-1/ACDL in Global Thin Cirrus Cloud Detection, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8530, https://doi.org/10.5194/egusphere-egu25-8530, 2025.
The BELLA measurement campaign took place at the CNR-IMAA Atmospheric Observatory (CIAO), where a large ensemble of instruments, including ceilometers, a Raman lidar, a wind Doppler lidar, a Ka band Doppler radar, a microwave radiometer and different types of in-situ sensors, were operated on a continuous basis over the period April-June 2024. The measurement effort also benefitted from the continous operation throughout the campaign duration of the Raman lidar system CONCERNIG Lidar, located approx. 7 km south-eastward of CIAO, at University of Basilicata in Potenza. All lidar systems involved in the measurement campaign were operated with high space and time resolution, typically 5-10 m and 10 sec, respectively, with vertical profiling capability both in daytime and nighttime for different atmospheric components/variables, including water vapour mixing ratio, CO2 mixing ratio, temperature and particle (aerosol and clouds) optical (backscatter/extinction) properties. This measurement capability, relying on different ABL tracers/properties is very effective in the characterization of the Atmospheric Boundary Layer structure and depth. Estimates of the ABLH obtained from the different parameters measured by CONCERNING are compared with those obtained from the radiosonde and Raman lidar measurements at CIAO, properly revealing differences associated with the different approaches and with atmospheric variability. In this work our attention is focused on two specific case studies (15-16 April 2024 and 28 April-01 May 2024), with results revealing a good agreement, quantified in terms of absolute and percentage BIAS, between the different sensors and approaches.
Acknowledgment
The authors acknowledge Next Generation EU Mission 4 “Education and Research” - Component 2: “From research to business” - Investment 3.1: “Fund for the realization of an integrated system of research and innovation infrastructures” - Project IR0000032 – ITINERIS.
How to cite: Summa, D., Di Girolamo, P., Di Paolantonio, M., De Rosa, B., Gandolfi, I., D'amico, G., Rosoldi, M., Mytilinaios, M., Papanikolaou, C. A., Papagiannopoulos, N., Marra, F., and Mona, L.: Multi product comparison during BELLA-ABL Campaign across different Lidar System, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2757, https://doi.org/10.5194/egusphere-egu25-2757, 2025.
Posters on site: Tue, 29 Apr, 08:30–10:15 | Hall X5
The Cloud and Aerosol Lidar for Global Scale Observations of the Ocean-Land-Atmosphere System (CALIGOLA) is an advanced multi-purpose space lidar mission with a focus on atmospheric and oceanic observation aimed at characterizing the Ocean-Earth-Atmosphere system and the mutual interactions within it. This mission has been conceived by the Italian Space Agency (ASI) with the aim to provide the international scientific community with an unprecedented dataset of geophysical parameters capable of increasing scientific knowledge in the areas of atmospheric, aquatic, terrestrial, cryospheric and hydrological sciences. The Italian Space Agency is partnering with NASA on this exciting new space lidar mission. The mission is planned to be launched in the time frame 2031-2032, with an expected lifetime of 3-5.
Exploiting the three Nd:YAG laser emissions at 354.7, 532 and 1064 nm and the elastic (Rayleigh-Mie), depolarized, Raman and fluorescent lidar echoes from atmospheric and ocean constituents, CALIGOLA will carry out multi-wavelength profile measurements of the backscatter, extinction and fluorescent coefficient and the depolarization ratio of atmospheric and ocean particles. These measurements will enable determinations of the microphysical and dimensional properties of atmospheric aerosols and clouds and their typing. Measurements of ocean optical properties will document phytoplankton seasonal and inter-annual dynamics and will improve understanding on marine biogeochemistry, the global carbon cycle, and responses of plankton ecosystems to climate variability. One specific measurement channel at 685 nm will be dedicated to fluorescence measurements from atmospheric aerosols and marine chlorophyll, for the purpose of aerosol typing and characterization of phytoplankton nutrient stress and primary production. CALIGOLA will provide accurate measurements of small-scale variability in earth surface elevation, primarily associated with variations in the ice and snow, terrain, and terrestrial vegetation height (e.g., forest canopies).
Phase A studies, commissioned by the Italian Space Agency to Leonardo S.p.A. and focusing of the technological feasibility of the laser source and the receiver, were conducted from October 2022, while Phase A/B1 activities for the payload, platform, and end-to-end system will start in January-February 2025. Scientific studies in support of the mission are ongoing, commissioned by the Italian Space Agency to University of Basilicata (KO: November 2021) and ISMAR-CNR (KO: September 2023). In September 2023, NASA-LARC initiated a pre-formulation study to assess the feasibility of a possible contribution to the CALIGOLA mission focused on development of the detection system and sampling chain and the implementation of data down link capabilities. The pre-formulation study ended in September 2024, the Mission Concept Review was successfully completed, and a phase A/formulation study has been finalized in preparation for a System Requirements Review, which should start shortly. This presentation will provide details on current status and future steps of this groundbreaking multidisciplinary lidar mission.
How to cite: Di Girolamo, P. and the CALIGOLA Team: The Cloud and Aerosol Lidar for Global Scale Observations (CALIGOLA): Overview of the current status and future steps of a groundbreaking multidisciplinary Mission, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8567, https://doi.org/10.5194/egusphere-egu25-8567, 2025.
How to cite: Chen, B.: The First Validation of Aerosol Optical Parameters Retrieved from the Terrestrial Ecosystem Carbon Inventory Satellite (TECIS) and Its Application, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15492, https://doi.org/10.5194/egusphere-egu25-15492, 2025.
We present ongoing work within the Land-Atmosphere Feedback Initiative (LAFI) [1]. LAFI is funded by the Deutsche Forschungsgemeinschaft (DFG) and is located at the University of Hohenheim, Stuttgart. LAFI's objective is to quantify and understand land-atmosphere feedbacks by utilizing synergetic observations and simulations in an interdisciplinary way. One aspect is covered by this work, which aims to provide a better understanding of fluxes in the convective boundary layer (CBL), especially the latent and sensible heat flux. The focus lies on entrainment fluxes in the interfacial layer (IL), the uppermost layer of the CBL, which marks the transition to the free atmosphere (FA).
A key aspect of this work is setting up a comprehensive dataset. This should capture all relevant variables such as temperature, humidity, and wind of the lower atmosphere at high spatial and temporal resolutions for as many cloud-free CBL situations as possible. Accordingly, simultaneous and high-resolution data from the synergetic use of different lidar systems will be used (see [2]) and processed (see [3]). Next, we will analyze this data for the driving variables and possible parameterizations of the latent and sensible heat flux.
We have already started this work by building a dataset containing data from the Atmospheric Radiation Measurement Climate Research Facility (ARM) Southern Great Plains (SGP) site in Oklahoma, USA, and testing a similarity relationship for the latent heat flux in the IL in [4].
Corresponding first results could not confirm the proposed similarity relationship for the latent heat flux in the IL from [2] and will be presented at the conference. Additionally, correlations of the flux with other measured variables, as well as an example case representative for the pool of selected cases will be shown.
In the coming months, we will expand the dataset to other measurement campaigns, like the synergy of Raman and Doppler lidar systems within LAFI in 2025.
References:
[1] https://www.lafi-dfg.de/
[2] Wulfmeyer, Volker et al. (2016): Determination of Convective Boundary Layer Entrainment Fluxes, Dissipation Rates, and the Molecular Destruction of Variances: Theoretical Description and a Strategy for Its Confirmation with a Novel Lidar System Synergy. In Journal of the Atmospheric Sciences 73 (2), pp. 667–692. DOI: 10.1175/JAS-D-14-0392.1
[3] Behrendt, Andreas et al. (2020): Observation of sensible and latent heat flux profiles with lidar. In Atmos. Meas. Tech. 13 (6), pp. 3221–3233. DOI: 10.5194/amt-13-3221-2020
[4] von Klitzing, Linus (2024): Latent Heat Entrainment Flux Similarity Relationships for the Convective Boundary Layer. Master's dissertation. University of Hohenheim, Stuttgart. Institute of Physics and Meteorology
How to cite: von Klitzing, L., Lange, D., Turner, D. D., Behrendt, A., and Wulfmeyer, V.: How can the Latent Heat Flux in a Convective Boundary Layer be Described? , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3558, https://doi.org/10.5194/egusphere-egu25-3558, 2025.
We studied the convective boundary layer (CBL) processes and surface fluxes long-term statistics by using a combination of two Doppler lidars (DLs) and an eddy-covariance station (EC) at the Land-Atmosphere Feedback Observatory (LAFO), Stuttgart, Germany (Abbas et al., 2024). At LAFO (Späth et al, 2023), one DL is continuously operated in vertical pointing mode, while the second is in six-beam scanning mode, both providing high-resolution data with resolutions of 1 s and 30 m. From this combination of DLs, we derived the profiles of vertical wind variance (Lenschow et al, 2000; Wulfmeyer et al, 2024), horizontal wind variance and turbulent kinetic energy (TKE) as well as CBL depth 𝑧𝑖 (Bonin et al., 2017; Bonin et al., 2018). The surface turbulent fluxes are acquired from an EC station in the agricultural fields of our university ~500 m away from the DLs. Daytime statistics are derived from 20 convective days from May to July 2021 with cloud cover < 40%. In this data set, we found a maximum of the CBL height averaged over all these days ⟨𝑧𝑖⟩ of (1.53 ±0.07) km at 13:30 UTC, which is about 2 hours after local noon. We found counter-clockwise hysteresis patterns between the CBL height and the surface fluxes. In the development phase, these relationships were approximately linear. In the early afternoon, the relationships reached a peak phase with both large fluxes and high values of ⟨𝑧𝑖⟩. At 12:00 UTC, just after local noon, the maximum values of vertical, horizontal, and total TKE were 0.55 m2s-2, 1.26 m2s-2 and 1.71 m2s-2 at heights of (0.30±0.06)⟨𝑧𝑖⟩ , (0.56±0.06)⟨𝑧𝑖⟩, and (0.40±0.06)⟨𝑧𝑖⟩, respectively. In the decay phase in the later afternoon, the relationships show non-linear patterns with larger values of ⟨𝑧𝑖⟩ for the same surface fluxes than in the morning. Furthermore, we analyzed relationships between the vertical and horizontal wind components and total TKE. Also, here, we found non-linear patterns in the three CBL phases.
Abbas, S. S., et al., 2024, https://doi.org/10.5194/egusphere-2024-3878
Späth et al., 2023, https://doi.org/10.5194/gi-12-25-2023
Lenschow et. al., 2000, https://doi.org/10.1175/1520-0426(2000)017<1330:MSTFOM>2.0.CO;2
Wulfmeyer et al., 2024, https://doi.org/10.5194/amt-17-1175-2024
Bonin et. al., 2017, https://doi.org/10.5194/amt-10-3021-2017
Bonin et. al., 2018, https://doi.org/10.1175/JTECH-D-17-0159.1
How to cite: Abbas, S. S., Behrendt, A., Branch, O., and Wulfmeyer, V.: Relationships Between Surface Fluxes and Boundary Layer Dynamics: Statistics at the Land-Atmosphere Feedback Observatory (LAFO), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11218, https://doi.org/10.5194/egusphere-egu25-11218, 2025.
We present the development progress of our compact multi-field-of-view lidar units for investigating small- to large-scale processes in the atmosphere. Matched narrowband laser and receiver enable precise daylight aerosol measurements with high aerosol visibility and high Doppler wind sensitivity in the troposphere/stratosphere and above. We present recent results with focus on extended measurement capabilities of our transportable systems.
Daylight capable Doppler lidars are complex systems particularly as lidar arrays require compact units with automated functionality. To study the 3-dimensional structure of small- to large-scale atmospheric processes we developed a universal Doppler lidar platform with multiple fields of view. All required technologies are included for studying Mie scattering (aerosols), Rayleigh scattering (air molecules), and resonance fluorescence (potassium atoms) from the troposphere (5 km) to the thermosphere (100 km). We developed unique frequency scanning laser and filter techniques that enable multiple observations (wind, temperature, aerosols, metal density). The combination of narrowband emitter and receiver allow a spectral high resolved characterization of the backscattered Doppler signals with a high wind sensitivity and aerosol visibility. Our current developments focus on enhancing lidar measurement capabilities of multiple parameters together with transferring the technology into industry (Project LidarCUBE) and demonstration of lidar array with enhanced daylight capability (EULIAA – European Lidar Array for Atmospheric Climate Monitoring). We will show recent results of our unique lidar technique with focus on aerosol measurements and more.
How to cite: Froh, J., Höffner, J., Mauer, A., Mense, T., Eixmann, R., Baumgarten, G., Munk, A., Scheuer, S., and Strotkamp, M.: Network Doppler Lidar for simultaneous multi-parameter observations, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11468, https://doi.org/10.5194/egusphere-egu25-11468, 2025.
Despite significant advancements in atmospheric observation techniques, the thermodynamic structure of the atmospheric boundary layer (ABL) remains largely unexplored due to the scarcity of suitable high-resolution remote sensing measurements. Over the past six years, the Atmospheric Raman Temperature and Humidity Sounder (ARTHUS), an automated profiler based on the Raman lidar technique (Lange et al., 2019), has participated in several ground- and ship-based measurement campaigns (Stevens et al., 2021; Flamant et al., 2021). These campaigns have demonstrated ARTHUS's capability to resolve critical atmospheric features, such as turbulent fluctuations and their statistics with high temporal and spatial resolution.
In combination with Doppler lidars, ARTHUS enables profiling of sensible and latent heat fluxes within the convective ABL, thereby supporting the investigation of flux-gradient relationships (Wulfmeyer et al. 2016, Behrendt et al., 2020). These capabilities make ARTHUS a powerful tool for advancing process studies of land-atmosphere interactions, enhancing weather and climate monitoring, validating atmospheric models, and improving data assimilation techniques. We present examples from several field campaigns with respect to the observation of diurnal cycles of profiles of mean and turbulent variables.
An eye-safe Nd:YAG laser with 20 W at 355-nm is used as transmitter. A 40-cm receiving telescope collects backscattered light providing independent measurements of temperature (T), water vapor mixing ratio (WVMR), CO2 concentration, particle extinction coefficient, and particle backscatter coefficient.
ARTHUS has proven its reliability during extended operations at the Land Atmosphere Feedback Observatory (LAFO) at the University of Hohenheim and across various field campaigns under diverse atmospheric conditions. As part of the Land-Atmosphere Feedback Initiative (LAFI, Wulfmeyer et al. 2024), ARTHUS will extend its capabilities to include scanning measurements from the surface through the ABL, capturing three-dimensional turbulent structures with a focus on entrainment processes. The campaign will take place between March and August 2025 at the LAFO site. For the first time, ARTHUS will deliver comprehensive maps of T, WVMR, and CO₂, especially near the surface and canopy but also up to the top of the ABL offering unprecedented insights into land-atmosphere feedback. At the conference, highlights of the first LAFI measurements will be shown.
References:
Lange et al. 2019, https://doi.org/10.1029/2019GL085774
Stevens et. al. 2021, https://doi.org/10.5194/essd-2021-18
Flamant et al. 2021, https://doi.org/10.1007/s42865-021-00037-6
Behrendt et al. 2020, https://doi.org/10.5194/amt-13-3221-2020
Wulfmeyer et al. 2016, https://doi.org/10.1175/JAS-D-14-0392.1
Wulfmeyer et al. 2024, https://doi.org/10.5194/egusphere-egu24-10102
How to cite: Lange Vega, D., Behrendt, A., and Wulfmeyer, V.: Scanning Measurements With an Automated Temperature and Moisture Lidar in the Atmospheric Boundary Layer, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7552, https://doi.org/10.5194/egusphere-egu25-7552, 2025.
We will give an update of our recent activities regarding automated high-resolution temperature and humidity lidar.
The Raman lidar ARTHUS (Atmospheric Raman Temperature and HUmidity Sounder) of University of Hohenheim is an automated instrument with continuous operation (Lange et al., 2019; Wulfmeyer and Behrendt, 2022). Besides being operated during several field campaigns elsewhere, ARTHUS is usually located at the LAFO (Land Atmospheric Feedback Observatory) near the agricultural research fields of our university. Here, in addition, three scanning Doppler lidars, a Doppler cloud radar, two meteorological 10-m towers with eddy-covariance stations, as well as surface and sub-surface sensors are collecting routinely data. These data are combined with detailed vegetation analyses.
ARTHUS is an eyesafe Raman lidar using a diode-pumped Nd:YAG laser as transmitter. Only the third-harmonic radiation at 355 nm is – after beam expansion – transmitted into the atmosphere. The laser power is about 20 W at 200 Hz repetition rate. The receiving telescope has a diameter of 40 cm. A polychromator extracts the elastic backscatter signal and four inelastic signals, namely the vibrational Raman signal of water vapor and CO2 molecules, and two pure rotational Raman signals. The raw data is stored with a resolution of 7.5 m and typically 1 to 10 s. All five signals are simultaneously analyzed and stored in both photon-counting (PC) mode and voltage (so-called “analog” mode) in order to make optimum use of the large intensity range of the backscatter signals covering several orders of magnitude. Primary data products are temperature, water vapor mixing ratio, carbon dioxide mixing ratio, particle backscatter coefficient, and particle extinction coefficient. The high resolution allows studies of boundary layer turbulence (Behrendt et al, 2015) and - in combination with the vertical pointing Doppler lidar - sensible and latent heat fluxes (Behrendt et al, 2020).
Further refined lidars like ARTHUS are offered by the company Purple Pulse Lidar Systems (www.purplepulselidar.com). Meanwhile three more systems have been built and are operating.
At the conference, we will present the recent advances in these powerful automated temperature and humidity lidars and show highlights of the measurements.
References:
Behrendt et al. 2015, https://doi.org/10.5194/acp-15-5485-2015
Behrendt et al. 2020, https://doi.org/10.5194/amt-13-3221-2020
Lange et al. 2019, https://doi.org/10.1029/2019GL085774
Wulfmeyer and Behrendt 2022, https://doi.org/10.1007/978-3-030-52171-4_25
How to cite: Behrendt, A., Lange, D., and Wulfmeyer, V.: Recent Advances in Automated Temperature and Humidity Lidar, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7172, https://doi.org/10.5194/egusphere-egu25-7172, 2025.
Our Rayleigh lidar systems provide temperature profiles up to 100 km altitude at both a site at southern hemisphere mid-latitudes and at South Pole. Very strong orographic gravity waves dominate in the lee of the Southern Andes in winter, a region proximate to the polar vortex edge where strong winds prevail. In contrast, despite being situated within the stable polar vortex core, continuous but weaker gravity waves are observed above Amundsen-Scott station at South Pole. Potential sources for these waves include catabatic winds flowing across the Transantarctic Mountains – which also give rise to polar stratospheric clouds-, polar vortex dynamics, or lateral progagation from mid-latitudes. We present examples of gravity wave measurements and statistical analyses derived from our multi-year, ongoing datasets.
How to cite: Kaifler, N. and Kaifler, B.: Gravity waves observed by lidar at the center and edge of the Southern polar vortex, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12951, https://doi.org/10.5194/egusphere-egu25-12951, 2025.
Doppler Wind LiDARs (DWLs) are remote sensing devices that measure wind speed and direction by analysing the Doppler shift of the light backscattered from atmospheric particles along the lidar beam's line of sight. Hence, DWLs are extensively employed in boundary layer meteorology to analyse wind flow due to their ability to provide high-resolution wind measurements. Recently, there has been growing interest in deploying DWLs in urban environments, where mast-based cup anemometers or sonic anemometers face challenges. However, DWL scanning techniques typically assume a homogeneous, stationary wind field, assumptions which often break down in urban boundary layers due to turbulence caused by buildings and complex topography that significantly influences wind profiles. Moreover, the selection of DWL scanning patterns and their configuration should be carefully tailored to the specific application.
One of the most-used scanning methods for measuring vertical wind velocity profiles is the Velocity Azimuth Display (VAD). The technique involves scanning the laser beam around the zenith in a conical pattern at a fixed elevation angle. However, completing the full 360° requires a finite time, during which the wind speed is assumed to be constant. Additionally, if the wind varies significantly within the sampling volume (e.g., due to turbulence or flow inhomogeneity) the calculated wind profiles may be inaccurate.
Large-Eddy Simulation (LES), with a sufficiently high grid resolution to resolve turbulent motions, provides a means to evaluate potential errors in DWL sampling strategies. This study uses a Virtual Doppler LiDAR (VDL) tool (Rahlves et al., 2022) within the Parallelized Large-Eddy Simulation Model (PALM, version 6.0) to estimate velocity profiles derived from simulated radial velocities along virtual laser beam paths under the VAD scheme. The research is part of the ASSURE Project (Across-Scale Processes in Urban Environments), which focuses on Bristol, UK. The project investigates urban wind flow using DWLs deployed across the city, employing scanning strategies utilised during a one-year field campaign beginning in May 2024.
Bristol was chosen for its compact urban layout and distinct topographic features, including the Avon Gorge and a central valley. The city serves as a case study for examining urban wind dynamics. This study's objectives are twofold: (1) to identify and quantify errors between the vertical wind profile derived from a VAD scan using the VDL and the profile directly taken from the PALM model and (2) to facilitate comparisons between PALM-simulated wind profiles and observations from ground-based DWL. By addressing the discrepancies arising from topographically induced flow, this research aims to enhance the reliability of DWL data in urban settings and improve our understanding of urban boundary layer processes. Results will be presented for a case study of flow channelled by a deep valley interacting with a city-centre boundary layer.
Rahlves, C., Beyrich, F., and Raasch, S. (2022). ‘‘Scan strategies for wind profiling with Doppler lidar – an large-eddy simulation (LES)-based evaluation’’, Atmospheric Measurement Techniques, 15(9), 2839-2856
How to cite: Escobar-Ruiz, V., Barlow, J., and Xie, Z.-T.: Evaluating Wind Velocity Measurement Errors in Ground-Based Doppler LiDAR Using Virtual Doppler LiDAR and Large Eddy Simulation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4413, https://doi.org/10.5194/egusphere-egu25-4413, 2025.
Carbon dioxide is the most important greenhouse gas caused by emissions from human activities. Nevertheless, little is known about its distribution in the atmposphere. Thus, continuous CO2 measurements not only on the ground but also in higher altitudes are key to improve our understanding of radiative forcing. Therefore, ground-based lidar systems with their ability of range-resolved CO2 measurements are particularly interesting. In the recent two years, we have developed and incorporated a new channel to our ground-based Raman lidar system ARTHUS ("Atmospheric Raman Temperature and HUmidity Sounder") [1] and successfully collected more then 70 days of CO2 profiles at the “Land-Atmosphere Feedback Observatory” (LAFO), in Stuttgart, Germany [2]. We utilize the 2ν2 CO2 Raman line, which is well separated from Raman lines of other atmosphere gases, especially O2. With the current setup, we profile CO2, temperature and humidity as well as particle extinction and particle backscatter coefficients in five receiver channels. The first CO2measurements in 2023 with a preliminary calibration where already presented at the EGU24 [3]. Since then, the laser power has been doubled while still being an eye-safe system. With some other improvements in addition, the integration times needed at night and for a resolution of 300 m are for example 1.5 hours for an uncertainty of 1.5 ppm and 2 hours for an uncertainty of 2 ppm at altitudes of 500 m and 1 km, respectively.
We are currently (January 2025) adding a 2-mirror scanner to the system. With this, we will much better calibrate our CO2 mixing ratio with low-level scans near our ground-based in-situ sensors located at the LAFO site. The scanning measuements of the CO2 concentration will provide insights in its distribution around the surface sensors and enable us to identify and quantify local carbon sources and sinks. We will present the recent approaches and first scanning measurements at the EGU25.
References:
[1] Lange, D. et al.: Compact Operational Tropospheric Water Vapor and Temperature Raman Lidar with Turbulence Resolution. Geophys. Res. Lett. (2019). DOI: 10.1029/2019GL085774
[2] Späth, F., S. Morandage, A. Behrendt, T. Streck, and V. Wulfmeyer, 2021: The Land-Atmosphere Feedback Observatory (LAFO). EGU21-7693 (2021). DOI: 10.5194/egusphere-egu21-7693
[3] Schumacher, M., D. Lange, A. Behrendt, V. Wulfmeyer, 2024: Measurements of CO2Profiles in the Lower Troposphere with the new Raman Lidar Channel of ARTHUS. EGU24-9219 (2024). DOI: 10.5194/egusphere-egu24-9219
How to cite: Schumacher, M., Lange, D., Behrendt, A., and Wulfmeyer, V.: CO2 Measurements with Raman Lidar in the Lower Troposphere , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8872, https://doi.org/10.5194/egusphere-egu25-8872, 2025.
Methane (CH4) is the second anthropogenic greenhouse gas (GHG) in the atmosphere that contributes to the global warming after CO2. If the methane emissions have a unique sink by OH oxidation, the various different sources, both anthropogenic (around 2/3) and natural, make complex the understanding of its atmospheric concentration. On the anthropogenic side (mainly gas exploitation and burning) it is fundamental to have a tool to verify inventories at different scales (from local methanizer to megacity) and prevent production network leakage in the atmosphere. As for surface-atmosphere exchanges of CO2, it is fundamental to study at different scales the spatial pattern and magnitude of the natural CH4 sources (biogenic anaerobic degradation of organic matter in wetlands, landfill and waste, livestock, rice cultivation, thermite, geological sources) and to understand their evolution with the global warming.
Lidar has an important role to play in such topic as it can make: (i) a 3D mapping of CH4 concentration in anthropogenic plumes, (ii) vertical profiles to study transport processes in the atmosphere, (iii) even measure direct flux and (iv) provide CH4 Earth global measurements from a space platform as it will be for MERLIN CH4 integrated path differential absorption lidar CNES/DLR ongoing mission.
A new ground-based Differential Absorption Lidar (DIAL) for atmospheric methane (CH4) profiling has been developed at LMD. The lidar emitter relies on a new hybrid fibered/bulk Er:YAG laser that delivers dual On/Off 8 mJ/ 300 ns pulses at a repetition frequency of 1 kHz in the methane line triplet at 1645.55 nm and out of at 1645.3 nm. It is associated with a direct detection receiver with a 50cm diameter telescope, a 2-nm linewidth interference optical filter, a near infrared photomultiplier (PMT) and a data acquisition and real time signal processing system working both in analogic and photon counting mode depending the application. First horizontal and vertical measurements in the atmosphere have been achieved and compared with in situ sensor and will be presented at the conference.
How to cite: Edouart, D., Gibert, F., and Cénac, C.: 1.65 µm CH4 ground-based differential absorption lidar measurements in the atmosphere, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16402, https://doi.org/10.5194/egusphere-egu25-16402, 2025.
This study introduces the development and application of the advanced scanning LiDAR system, SMART LiDAR MK-II(Samwoo TCS co., Ltd), designed for the early detection of wildfires and industrial fires. Traditional fire detection methods face limitations due to diverse atmospheric conditions, topographical factors, and variability in fire and smoke characteristics. To address these challenges, monitoring systems with spatial resolutions below 30 meters are essential. The SMART LiDAR MK-II employs dual wavelengths (532 nm and 1064 nm) and provides 360° observations with an angular resolution of approximately 3° within a 30-minute interval, enabling the real-time detection of smoke and particulate matter under various environmental conditions.
The system was validated through field deployment in the Sihwa Industrial Complex, South Korea, during a fire at an automotive painting factory on July 22, 2024. Positioned at a monitoring height of 55 meters and approximately 20 meters from the fire source, the SMART LiDAR MK-II detected smoke with peak PM10 and PM2.5 concentrations of 724 µg/m³ and 334 µg/m³, respectively. The smoke plume was observed dispersing over 5 km northward, influenced by prevailing winds. Furthermore, the system successfully captured the temporal reduction in particulate matter concentrations following fire suppression, demonstrating its capability to monitor emission dynamics and dispersion patterns.
Currently, SMART LiDAR MK-II is undergoing rigorous waterproof and dustproof testing to ensure operational reliability under diverse conditions, with commercialization in progress. This cutting-edge technology represents a significant advancement in LiDAR-based fire detection, offering high spatial resolution, sensitivity, and reliability for real-time monitoring of smoke emissions and atmospheric impacts. The results highlight the transformative potential of SMART LiDAR MK-II to enhance global fire detection and environmental monitoring capabilities.
Acknowledgment: This research was supported by a grant (2023-MOIS-20024324) from the Ministry-Cooperation R&D Program of Disaster-Safety funded by the Ministry of Interior and Safety (MOIS, Korea).
How to cite: Kim, K., Kim, S., Lee, G., Park, J.-M., Oh, S., Sung, M.-K., Noh, Y., Lee, K., Kim, Y. J., Choi, W., Choi, S., Choi, C., Hong, C.-S., Kim, S., Jung, Y., Yang, I., and Choi, B.-J.: Advanced Scanning LiDAR for Real-Time Detection of Wildfires and Industrial Fires, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10819, https://doi.org/10.5194/egusphere-egu25-10819, 2025.
The Barcelona Dust Regional Center (BDRC) provides daily forecasts of dust optical depth and dust surface concentrations, as part and coordination entity of the Northern Africa, Middle East and Europe (NAMEE) node of the World Meteorological Organization Sand and Dust Storm Warning Advisory and Assessment System (WMO SDS-WAS). Dust optical depth forecasts from the NAMEE SDS-WAS ensemble show a relatively good agreement, while the forecasts of dust surface concentrations show larger variability between models. Moreover, the consistency between dust optical depth, as an integrated column quantity, and surface concentration forecasts remains challenging.
Since July 2024, vertical profiles of dust concentrations from the Multiscale Online Nonhydrostatic AtmospheRe Chemistry (MONARCH) model of the SDS-WAS ensemble have been made public on the BDRC website. This study presents the first evaluation of this new forecast product through comparisons with lidar observations, focusing on vertical profiles of total and dust extinction coefficients. Specifically, we used lidar measurements from the NASA Micro-Pulse Lidar Network (MPLNET) in the Mediterranean and North Africa area. While the comparison of the total extinction coefficient between MONARCH (550 nm) and MPLNET (532 nm) can be performed directly but is affected by unaccounted aerosols (e.g. sea salts, anthropogenic aerosols), the extraction of dust extinction coefficient from MPLNET products required additional processing. To this purpose, the POLIPHON algorithm was exploited to obtain the lidar-derived dust component from the total aerosol load and enable a fair intercomparison with modeled dust profiles. Initial descriptive and quantitative results confirm the model’s reliability in forecasting and predicting dust vertical profile characteristics.
Building on this evaluation, we explore the potential of leveraging lidar data to improve the dust ground concentration estimates of the MONARCH model forecasts. The proposed approach explores empirical adjustments of the model's surface concentration using lidar observations and validates these improvements against independent ground-based PM10 measurements collected by the European Environment Agency (EEA). The analysis is performed for three European sites, namely Tenerife, Barcelona, and El Arenosillo, for the period from July 2024 to January 2025.
The expanded aim of this work is to assess the feasibility of utilizing next-generation space-borne lidar systems, such as EarthCARE (Cloud, Aerosol, and Radiation Explorer), to enhance global dust surface concentration estimations from model forecasts.
This study highlights the synergy between observations and modeling, demonstrating how lidar observations could be exploited for correcting and improving model performance at both regional and global scales.
How to cite: Gilè, C., Emili, E., Escribano, J., Ilic, L., Jorba Casellas, O., and Perez Garcia Pando, C.: Evaluating the MONARCH Model with Lidar Data: A Step Toward Improving Global Dust Surface Concentrations, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9052, https://doi.org/10.5194/egusphere-egu25-9052, 2025.
With the advances in ground-based remote sensing technology, measurement networks of automatic aerosol lidar-ceilometers are developing rapidly across Europe and worldwide. Characterising inter-instrument variability of sensors is crucial to assessing uncertainties in observational campaigns, networks, and for data assimilation. It allows the determination of thresholds that need to be exceeded for the detection of meaningful atmospheric differences between observations obtained at different locations (e.g. urban vs rural).
We co-locate six Vaisala CL61 automatic lidar-ceilometers at the SIRTA atmospheric observatory (Palaiseau, France) for a period of ten days to quantify instrument-related differences in several observed variables: profiles of attenuated backscatter and the linear depolarisation ratio (LDR), as well as derived cloud variables, such as cloud base height (CBH) and cloud cover fraction (CCF), and mixed-layer height. Analysing intervals between 5 and 60 min, median absolute differences between sensors are used to quantify inter-instrument uncertainties. For backscatter and LDR, we differentiate between conditions with rain, clear sky, and clouds, respectively.
The agreement between instruments is capable of resolving climatological differences in mesoscale conditions (5 - 50 km, e.g. across cities) for both profile variables and derived cloud variables and layer heights. However, differences exist and can be linked to signal-to-noise ratio (SNR) and atmospheric conditions. The median absolute inter-sensor differences for 15 min aggregation intervals (AD50) are 1.9 % for total CCF (excluding clear sky and fully overcast conditions) and 7.3 m for CBH. Cloud variables agree better for boundary layer clouds where the first (of five) cloud layer < 4 km agl. The mixed-layer height AD50 is 0 m. Median differences smaller than two instrument range gates (9.6 m) highlight the close inter-instrument agreement.
How to cite: Looschelders, D., Christen, A., Grimmond, S., Kotthaus, S., Dupont, J.-C., Fenner, D., Haeffelin, M., and Morrison, W.: A field intercomparison of inter-instrument variability of six co-located Vaisala CL61 lidar-ceilometers, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15242, https://doi.org/10.5194/egusphere-egu25-15242, 2025.
Air pollution is a persistent environmental and public health challenge, particularly in industrial areas characterized by diverse and diffuse emission sources. This study demonstrates the application of an advanced scanning LiDAR system for real-time monitoring of particulate matter (PM2.5, PM10) and the detection of illegal emissions in Gyeonggi Province, South Korea. The system employs advanced remote sensing technology, enabling 360° atmospheric scans within a 5 km radius at 30-minute intervals, with a spatial resolution of 30 meters.
During its deployment in the Sihwa National Industrial Complex, home to over 978 industrial facilities, the LiDAR system identified 192 potential illegal emission sources. Subsequent investigations confirmed 22 violations of environmental regulations, resulting in regulatory actions such as facility shutdowns and legal proceedings. The deployment led to a measurable improvement in air quality, evidenced by a reduction of 2.4 μg/m³ in PM2.5 levels during the operational period.
The integration of LiDAR data with complementary environmental datasets enabled precise spatiotemporal analyses, enhancing the efficiency of regulatory enforcement and fostering effective inter-agency collaboration. The results underscore the system’s potential to overcome limitations of conventional point-source monitoring, offering an innovative tool for large-scale industrial air pollution management.
This study highlights the scalability and precision of scanning LiDAR technology as a critical asset for real-time air quality monitoring and regulatory compliance. The findings advocate for broader adoption of this technology in industrial settings globally, emphasizing its ability to address complex environmental challenges and promote sustainable industrial practices.
Acknowledgement: This research was supported by a grant (2023-MOIS-20024324) of Ministry-Cooperation R&D Program of Disaster-Safety funded by Ministry of Interior and Safety (MOIS, Korea) and Climate & Environment Division Scientific Environment Surveillance Team in Gyeonggi-do Province, Korea.
How to cite: Kim, S., Kim, K., Lee, G., Park, J., Oh, S., Sung, M., Kim, S., Jung, Y., Yang, I., Choi, B.-J., Choi, S., and Choi, C.: Real-Time Monitoring of Air Pollution and Detection of Illegal Emissions Using Advanced Scanning LiDAR Technology, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10784, https://doi.org/10.5194/egusphere-egu25-10784, 2025.
In this study we present a synergistic approach between lidar and photometer to separate volcanic ash and desert dust and, ultimately, to enhance lidar-based aerosol typing schemes. Typically, the lidar depolarization ratio measurements can be used to distinguish dust and ash with ash depolarization ratio reaching higher values. However, the variability of aerosol depolarization ratio makes it difficult to use it in automatic typing techniques. The imaginary part of refractive index when using in situ data shows stronger absorption than mineral dust; therefore, here, we make use of microphysical AERONET data to define the two aerosol classes (i.e., ash/dust). Then, trivariate Mahalanobis distance is estimated based on the real and imaginary parts of the refractive index and the single scattering albedo for any given AERONET measurement and the type is assigned. This information is then passed on in lidar aerosol typing algorithms and the aerosol type is allocated in the vertical dimension. The methodology is applied to the Potenza ACTRIS site in Italy during an intense desert dust event where an AERONET photometer and an ACTRIS lidar are collocated.
How to cite: Papagiannopoulos, N., Mytilinaios, M., Amodeo, A., D'Amico, G., Gumà-Claramunt, P., Papanikolaou, C. A., and Mona, L.: Enhancing lidar aerosol typing schemes: a lidar/photometer synergy, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18566, https://doi.org/10.5194/egusphere-egu25-18566, 2025.
Several studies [1,2] have shown the potential of polarization lidar to provide vertical profiles of aerosol parameters from which cloud condensation nuclei (CCN) and ice-nucleating particles (INP) number concentrations can be retrieved. The results are based on reliable of conversion factors between aerosol optical thickness and column-integrated particle size distribution based on Aerosol Robotic Network (AERONET) photometer observations. A crucial point regarding the efficacy of aerosol particles to act as CCN or INP depends on aerosol type.
AERONET Inversion Data (Level 1.5) for Thessaloniki station were analyzed over the period 2006-2021. Following [1,2], the Ångström exponent was used to separate the particles into pollution (AE > 1.6) and dust (AE < 0.5) dominated cases. To obtain a better classification of aerosols we utilize aerosol typing from CALIPSO. Only cases which are classified as either purely dust or polluted continental aerosols within 100km from Thessaloniki are selected. The Aerosol Optical Depth (AOD) at 440 nm and the Ångström exponent (AE) 440-870 were used to calculate the AOD at 532 nm, while the AOD at 1020 nm and the AE between 870-1020 nm were used to estimate the AOD at 1064 nm. The particle volume size distribution is derived for 22 discrete radius points, spaced logarithmically at equidistant intervals. The particle number concentration (n) for each radius interval is calculated by dividing the volume concentration by the particle volume and multiplying by the spectral integral width of 0.2716. The column value of n60 is the sum of number concentrations for radius classes 2 to 22 (>57 nm), while n100 is the sum for radius classes 4 to 22 (>98 nm). The INP-relevant column n250 is the sum of intervals 8–22 plus the mean of intervals 7 and 8, while n290 the sum of 8-22. To obtain particle extinction coefficient σ (or sigma) and n60, the AOD at 532 nm and the column n60 are divided by 1000 m. For urban particles, n60 (reservoir of CCN) and n250 (reservoir of INP) were used, while n100 (CCN) and n250 (INP) were used for dust particles. Following CALIPSO aerosol typing dust conversion factors was found equal to c100= 24.3±7.0 Mm cm-3, xd=0.78 ± 0.13 and c250= 0.30±0.03 Mm cm-3, while for polluted continental particles, were c60= 31.4 ± 9.0 Mm cm-3, xc= 0.94 ± 0.12 and c290= 0.089±0.002 Mm cm-3.
References:
[1] Mamouri, R.E. and Ansmann, A. Potential of polarization lidar to provide profiles of CCN- and INP-relevant aerosol parameters. Atmos. Chem. Phys. 2016, 16, 5905–5931. doi:10.5194/acp-16-5905-2016
[2] Georgoulias, A.; Marinou, E.; Tsekeri, A.; Proestakis, E.; Akritidis, D.; Alexandri, G.; Zanis, P.; Balis, D.; Marenco, F.; Tesche, M. and Amiridis, V. A First Case Study of CCN Concentrations from Spaceborne Lidar Observations. Remote Sens. 2020, 12, 1557. doi:10.3390/rs12101557
Acknowledgments: The research work was supported by the Hellenic Foundation for Research and Innovation (H.F.R.I.) under the “Basic Research Financing (Horizontal support for all Sciences), National Recovery and Resilience Plan (Greece 2.0)” (Project Number: 015144).
How to cite: Giannakaki, E., Archontoula, K., Aristeidis, G., and Ioannis, K.: Cloud Condensation Nuclei (CCN) and Ice Nucleating Particles (INP) conversion factors based on Thessaloniki AERONET station, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21533, https://doi.org/10.5194/egusphere-egu25-21533, 2025.
The study investigates the dynamics of the Boundary Layer (BL) over the Atlantic Ocean, with a focus on the region surrounding Cabo Verde, using a combination of ground-based PollyXT lidar, satellite lidar data from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), radiosondes, and European Centre for Medium-Range Weather Forecasts (ECMWF) model output. The comparison of CALIPSO lidar profiles with ECMWF reanalysis revealed strong correlations for BL top over open ocean regions but less agreement in dust-affected areas closer to the African continent. In these regions, satellite lidar indicated higher BL tops than those estimated by ECMWF, likely due to the existence of high of aerosol concentrations, which play a crucial role in shaping dynamics. Observations in Cabo Verde highlight distinctive Marine Atmospheric Boundary Layer (MABL) characteristics, such as limited diurnal evolution, but also show the potential for BL heights to reach up to 1 km, driven by factors like strong winds that increase mechanical turbulence. Additionally, this study illustrates the challenges in accurately determining the BL height using lidar and radiosondes, examining cases with strong inversions that prevent vertical mixing, but also weaker inversions that allow for the penetration of dust particles within BL. Integrating multiple observational sources and techniques is essential for validating remote sensing data and enhancing BL characterizations. The findings underscore the complex interactions between marine and dust-laden air masses over the Atlantic, which are essential for understanding the dynamic processes in aerosol-cloud interactions.
How to cite: Tsikoudi, I., Marinou, E., Tombrou, M., Giannakaki, E., Proestakis, E., Rizos, K., and Amiridis, V.: The desert dust impact on the Boundary Layer in the Atlantic, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16880, https://doi.org/10.5194/egusphere-egu25-16880, 2025.
South Korea faces complex air quality challenges arising from domestic emission sources driven by industrialization and urbanization, as well as seasonally influenced long-range transport pollutants from overseas. In particular, springtime dust storms and wintertime heating emissions both domestic and foreign converge to create a multifaceted air pollution environment. To effectively understand and manage these issues, accurately determining the Mass Extinction Efficiency (MEE) based on optical observations is essential. In this study, we refined MEE calculations by integrating LiDAR-based observations with ground-level measurements, analyzed variability as a function of aerosol origin, and simultaneously assessed the potential for indirect evaluation of atmospheric composition. Using a horizontal SCANNING LiDAR, we derived high-resolution, two-dimensional extinction coefficients near the surface and combined these data with hourly Particulate Matter (PM) observations from the AirKorea monitoring network. Employing the Ångström exponent to differentiate coarse mode particles (Ångström exponent ≈ 0) from fine mode particles (Ångström exponent ≈ 3), we calculated extinction coefficients for total, coarse, and fine aerosols. We then derived MEE values through three approaches: total extinction coefficient relative to PM10, coarse extinction coefficient relative to (PM10 – PM2.5), and fine extinction coefficient relative to PM2.5. To analyze aerosol origins, we used the HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory) model of NOAA(National Oceanic and Atmospheric Administration), which allowed us to evaluate mesoscale and regional source contributions and investigate their impact on MEE variability. Data from December 2021 to the present revealed substantial variations in MEE values depending on aerosol source regions and compositions. By offering a refined analytical framework tailored to South Korea’s unique climatic and geographical characteristics, this study provides valuable insights for improved air quality monitoring and predictive modeling.
"This research was supported by Particulate Matter Management Specialized Graduate Program through the Korea Environmental Industry & Technology Institute(KEITI) funded by the Ministry of Environment(MOE)"
How to cite: Yoon, J., Shin, J., Joo, S., Park, G., Kim, D., and Noh, Y.: A Study Mass Extinction Efficiency (MEE) Calculation and Variability Analysis by Aerosol Source Identification: Application of Horizontal Scanning Lidar and HYSPLIT Model, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8397, https://doi.org/10.5194/egusphere-egu25-8397, 2025.
Cirrus clouds play a critical role in Earth's energy balance by influencing radiative
processes, reflecting incoming solar radiation, and trapping outgoing infrared radiation. In the
Arctic, extreme conditions limit the observational networks and hinder direct measurements.
However, among various remote sensing tools, LIght Detection And Ranging (LIDAR)
emerges as one of a reliable tool for long-term monitoring of cirrus cloud optical properties
over the Arctic region. The extinction coefficient, derived from LIDAR measurements and
essential for evaluating the radiative effects of cirrus clouds, is strongly impacted by the
Multiple Scattering Factor (MSF). In this regard, the present study aims to estimate the MSF
by simulating LIDAR signals using the Monte Carlo method. The input parameters for the
Monte Carlo simulations include the geometry of the atmosphere and optical properties
(including extinction and Mueller matrix). Furthermore, the Mueller matrix is estimated based
on the size distribution and particle shape information acquired through the in-situ measurement
from the Balloon-borne Ice Cloud Particle Imager (B-ICI) instrument. The MSF contribution,
at least in part, depends on the characteristics of the LIDAR, particularly its Field of View. As
a result, new simulations are required, and previous results from older studies cannot be directly
applied.
The photon backscatter information obtained from the Analog and Photon
counting channels of the ground-based LIDAR instrument installed at IRF, Kiruna (68ºN,
20ºE), is utilised to estimate the cirrus cloud's optical properties. To address the instrument’s
non-linear behaviour at higher signal intensities, a glueing procedure is performed to merge the
Analog and the Photon counting signal. The resulting glued signal undergoes multiple
corrections, including background noise subtraction, signal-to-noise ratio enhancement, and
range corrections. The Dynamic Wavelet Covariance Transform (DWCT) technique is
deployed to the corrected LIDAR signal to estimate the cloud top and base altitude information.
Subsequently, an inversion technique incorporating MSF, such as the Sassen method, is chosen
for the current analysis.
The estimated cirrus cloud optical properties using the ground-based LIDAR will
subsequently be validated against EarthCARE’s ATmospheric LIDar (ATLID) satellite
observations. This study enhances the accuracy of cirrus cloud parameterisation, contributing
to improved climate models and a deeper understanding of Arctic cloud-radiative interactions.
How to cite: Gupta, G., Voleger, P., Kuhn, T., and Stenszky, J.: Estimation of the Optical properties of Arctic Cirrus Clouds: Insights fromLIDAR measurements and Monte Carlo simulations, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15418, https://doi.org/10.5194/egusphere-egu25-15418, 2025.
Contrails are local and thin anthropogenic clouds that are difficult to predict by numerical weather forecasting models. Given their local radiative impact, it is urgent to properly document their characteristics in order to improve their parametrization in weather models and evaluate their contribution to global warming. In the framework of the Climaviation project (Funded by the French Direction Générale de l’Aviation Civile (DGAC)), this study aims to quantify the optical, geometrical and microphysical characteristics of contrails at the SIRTA observatory in Palaiseau, France. We used a co-localised instrumental synergy composed of the Lidar IPRAL (a multichannel raman Lidar), a total sky camera, and aircraft flight altitudes to detect the occurrence of contrails over the site during the 2018-2023 period. Based on three (3) case studies, the particular and molecular integration methods are applied on the Lidar backscatter, to estimate the optical depth of contrails. Vertical profiles of temperature and relative humidity from Trappes radiosoundings are used to characterize the atmospheric conditions classified into three (3) categories of contrail evolution (non-persistent, persistent, and spreading). The results show that the optical thickness of contrails can reach 0.3 for contrails formed in a thick persistent layer. It is lower for contrails developing in a non-persistent layer. During daytime, the contrails contribute to reducing the surface downwelling and upwelling measured shortwave radiation in the order of 218 and 50 W m-2 respectively. Their impact on longwave radiation is relatively negligible.
How to cite: Dione, C., Dupont, J.-C., Caillault, K., Gourgue, N., Pietras, C., and Haeffelin, M.: Estimation of optical and microphysical characteristics of contrails using Lidar at SIRTA observatory, Paris, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11819, https://doi.org/10.5194/egusphere-egu25-11819, 2025.
Posters virtual: Tue, 29 Apr, 14:00–15:45 | vPoster spot 4
EGU25-21759 | Posters virtual | VPS19
Assessment of Atmospheric Pollen Presence in Urban Areas of Greece During CALIPSO OverpassesTue, 29 Apr, 14:00–15:45 (CEST) | vP4.5
Analysis of pollen events was conducted using Hirst-type volumetric samplers in Athens and Thessaloniki in combination with CALIPSO vertical aerosol profiles. While Hirst-type [1] volumetric samplers are used to confirm and characterize pollen at ground level, the understanding of pollen vertical distribution and transport is still limited. The utilization of Light Detection and Ranging (LIDAR) for identifying different pollen types is increasingly prevalent, as the depolarization ratio is related to the shape of the pollen particles while other non-spherical particle types are absent [2].
Samplers are situated on the buildings’ rooftops of the Physics and Biology Departments, in Athens and Thessaloniki, respectively. Following [2], intense pollen events are considered when the pollen concentration exceeds 400 grains m-3 for a minimum of two hours each day.
CALIPSO provides unique vertical profile measurements of the Earth’s atmosphere on a global scale [3], with the ability to distinguish between feature types (i.e., clouds vs. aerosol) and subtypes (i.e., marine, dust, clean continental). Only case studies where CALIPSO aerosol layers were classified as marine, dusty marine, dust, or polluted dust were analyzed.
Model simulations were used to exclude the presence of other depolarizing aerosol types. HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory) was used to trace the origin of the air masses. The atmospheric model RAMS/ICLAMS (Regional Atmospheric Modeling System/Integrated Community Limited Area Modeling System) was selected to describe dust and sea-salt emissions and transport.
Mean values of lidar-derived optical properties inside the detected pollen layers are provided from CALIPSO data analysis. Specifically, there are three observed aerosol layers, one over Athens (12-3-2021) and two over Thessaloniki (2-3-2020, 10-4-2020). Particulate color ratios of 0.652 ± 0.194, 0.638 ± 0.362, and 0.456 ± 0.284, and depolarization ratios of 8.70 ± 6.26%, 28.30 ± 14.16%, and 8.96±6.87 % for 12-3-2021, 2-3-2020 and 10-4-2020, respectively, were misclassified by CALIPSO as marine-dusty marine, dust and polluted dust. The pollen analysis conducted on the 12th of March 2021 indicated that the dominant pollen types were 69% Pinaceae and 24% Cupressaceae. On the 2nd of March 2020, Cupressaceae accounted for 97% of the total pollen, while on the 10th of April 2020, Carpinus represented 76% and Platanus 15%. Consequently, during periods of intense pollen presence, CALIPSO vertical profiles and aerobiological monitoring techniques may be used synergistically to better characterize the atmospheric pollen layers.
Acknowledgements
The research work was supported by the Hellenic Foundation for Research and Innovation (H.F.R.I.) under the “Basic Research Financing (Horizontal support for all Sciences), National Recovery and Resilience Plan (Greece 2.0)” (Project Number: 015144).
[1] J. M. Hirst, Annals of Applied Biology 39, 157-293 (1952).
[2] X. Shang et al., Atmos. Chem. Phys. 20, 15323–15339 (2020).
[3] D. M. Winker et al, BAMS 91, 1211–1229 (2010).
How to cite: Karageorgopoulou, A., Christos, S., Thanasis, G., Χiaoxia, S., Ioanna, P., Vassilis, A., and Elina, G.: Assessment of Atmospheric Pollen Presence in Urban Areas of Greece During CALIPSO Overpasses, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21759, https://doi.org/10.5194/egusphere-egu25-21759, 2025.
