Uncrewed Aircraft Systems (UAS) and tethered balloon systems (TBS) are transforming atmospheric research by enabling high-resolution, multi-instrument observations. To address long-standing gaps in planetary boundary layer (PBL) observations, particularly in the mixed layer and entrainment zone, we employed the Max Planck CloudKite, a tethered kite-balloon hybrid system, equipped with the latest generation of WinDarts. These versatile instruments provide continuous multi-parameter measurements of PBL dynamics for up to 20 hours. Each WinDart measures three-dimensional wind velocity, temperature, relative humidity, pressure, particle concentration (0.3–40 μm), carbon dioxide, and volatile organic compounds, offering unparalleled insights into PBL processes.
During the Pallas Cloud Experiment (September 2022) and the IMPACT campaign ("In-situ Measurement of Particles, Atmosphere, Cloud and Turbulence," May–June 2024) in Pallas, Finland, we deployed successive generations of WinDarts, achieving a cumulative flight time of nearly 370 hours. These campaigns yielded high-resolution datasets capturing turbulent fluxes of heat and momentum and interactions between the PBL and the free atmosphere.
This contribution presents findings from the IMPACT campaign, focusing on velocity-temperature interactions and their role in turbulence and vertical transport. The results demonstrate the value of TBS-based platforms in complementing UAS systems for atmospheric research and advancing our understanding of PBL processes.
To the left, the image shows two kite-balloons deployed with three WinDarts during a flight as part of the IMPACT field campaign. To the right, we show a lateral visualization of a WinDart highlighting its different components.
How to cite: Chávez-Medina, V., Khodamoradi, H., Bodenschatz, E., and Bagheri, G.: Max PlanckWinDarts: High-resolution measurements in the planteray boundarylayer with a tethered balloon, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13819, https://doi.org/10.5194/egusphere-egu25-13819, 2025.
From single crystal formation high in the atmosphere down to precipitating snowfalls at ground level no snowflake takes the same path through the air column. During descent snow-crystals grow, coalesce, break, and rime into graupel while interacting with the surrounding air. Among the well-studied effects of temperature and humidity super-saturation, the specific role of the various turbulence activities throughout the atmosphere remains elusive. This work uses uncrewed aerial vehicles (UAVs) as a flexible platform to study snowfall up to 120 meters above ground level during their most ‘turbulent end-of-lifetime’ as they descend through the atmospheric surface layer. The work is twofold. Firstly, a smaller commercially available DJI Mavic3E quadcopter equipped with an onboard telelens and CZZI GL10 searchlight is used to gather aerial photography of snowfall 3 meters away from the drone. Automated flight paths executed in an hourly deployment scan the air column and harvest 13407 snowflakes from 3351 images taken during nighttime experiments. Building on previous ground-imaging studies, we extract snowflake metrics for size, aspect ratio, complexity, and orientation angle at a 160μm-per-pixel image resolution. Our data suggests that snowflakes of high aspect ratio tend to glide in horizontal orientation while interacting with the turbulent atmosphere. Mapping our data over various height positions we find an overall 30% percent variability in snowflake growth, while variation in shape is found less prominent. Secondly, we present developments on an airborne microscopy system to shed further light on the intricate details of the snowflakes concerning their freefall behavior. Equipping a larger DJI Matrice600Pro hexacopter capable of carrying a 6kg payload with an Infinity K2-Distamax long-range microscope telescopic lens we increase the image resolution by a factor of ten and reach 16μm-per-pixel. We will present the various subsystems involved in imaging snowflakes outside the drone's flow envelope, including synchronizing a pulsed LED circuit to compensate for the large image distance and low numeric aperture. We will present the first snowflakes captured in freefall during the start of the 2024 snow season to demonstrate the feasibility of our airborne microscopy system in hovering flight.
How to cite: Muller, K., Camenzind, M., Shesterikov, I., Morandi, S., and Coletti, F.: Hovering a Microscope on a Drone: Development of UAV Based Systems for High-resolution Imaging of Falling Snow, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17544, https://doi.org/10.5194/egusphere-egu25-17544, 2025.
Climate change poses significant threats to ecosystems and human activities, necessitating urgent efforts to reduce greenhouse gas emissions. This requires new tools able to monitor and quantify emissions at the meso-scale, applicable to large industrial facilities, agricultural sites, landfills or natural areas such as forests or peatlands. To address this challenge, our project aims at developing a lightweight (< 4 kg) eddy covariance (EC) system embarked on a fixed-wing vertical take-off and landing (VTOL) uncrewed aircraft system, enabling precise measurements of greenhouse gases (CO2, CH4) and energy fluxes between the surface and the atmosphere over large and heterogeneous areas.
The system combines a five-hole turbulence probe (ADP) to measure three-dimensional wind and air temperature, along with a custom-fabricated diode laser spectrometer for CO2, CH4 and H2O concentrations. The gas analyzer is lightweight (2.1 kg), highly accurate (< 0.5 %), capable of rapid measurements (100 Hz) and optimized for high-speed mobile platforms.
A preliminary mobile EC system (comprising the ADP, a reference sonic anemometer and the custom gas analyzer) was mounted on a vehicular platform to evaluate the integrated sensor suite under real atmospheric conditions. Comparative analyses of instantaneous relative velocity components and turbulence spectra show close agreement between the two wind sensors, confirming the ADP’s suitability for integration into our VTOL-based EC system. Furthermore, the water vapor and CO2 concentration spectra indicate that the concentration sensor is well-suited for measuring atmospheric gases within a mobile EC setup. A continuous wavelet transform approach was applied to compute surface fluxes on agricultural fields near the road trip. Combined with a footprint analysis to study landscape heterogeneity, this lays the groundwork for a transition to a drone-based EC system.
A flight maneuver was conducted with the ADP-equipped VTOL under unstable atmospheric conditions to validate wind and air temperature measurements. Spectral analysis indicates that the airborne platform can capture actual atmospheric turbulence. Sensible heat flux was computed for this test flight, demonstrating our drone-based EC system’s potential to generate surface fluxes and emissions maps over heterogeneous landscapes.
As part of our future work, flight trials will be carried out to measure greenhouse gases (CO2 and CH4) and energy fluxes. These measurements will be compared against tower-based EC fluxes to evaluate the performance of the UAV-based system.
How to cite: Hoang, N. M., Bonne, J.-L., Dumelié, N., Parent, F., Moncourtois, V., Albora, G., Burgalat, J., Lauvaux, T., Abdallah, C., Herig-Coimbra, P.-H., Loubet, B., Donnat, L., and Joly, L.: Development of an airborne Eddy covariance system dedicated to greenhouse gases (CO2/CH4) and energy fluxes measurements of heterogeneous landscapes onboard fixed-wing UAV, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6449, https://doi.org/10.5194/egusphere-egu25-6449, 2025.
The WMO Uncrewed Aircraft Systems Demonstration Campaign (UAS-DC) was organised to measure the ability of a range of UAS to meet the requirements for operational upper air observations and to assess their ability to fill observational gaps in WIGOS GBON and/or RBON. Data were collected over a 7-month period from March to September 2024 and 3 Special Observing Periods were performed: during US March 2024 Eclipse, Paris Olympics and during 2024 ISARRA Flight Week Campaign in September, using WMO NetCDF data format standard, which were automatically converted to the BUFR format. These two standardised formats facilitated the widespread use of UAS weather observations by researchers and NWP modelling centres around the world. In addition to deploying a distributed trial network of UAS to test the concept, the campaign used the WMO Information System (Version 2.0, WIS 2.0) to provide real-time data to participating subscribers during the campaign. These highly flexible, accurate and environmentally friendly weather sensing UAS provide a new innovative observing system for National Meteorological and Hydrological Services (NMHSs) to fill observational gaps and subsequently improve numerical weather prediction capabilities. The UAS-DC provided insight into the potential use of crowd-sourced data from observations of opportunity collected by the delivering UAS. We present in this work an overview of the campaign, including a discussion of the methods, and the potential impact that UAS observations collected at regional scales may have, as indicated by initial studies conducted by NWP centres.
How to cite: OSullivan, D., Pinto, J., and Rivaben, N.: Preliminary results of World Meteorological Organization Uncrewed Aircraft Systems Demonstration Campaign (WMO UAS DC), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20826, https://doi.org/10.5194/egusphere-egu25-20826, 2025.
Weather significantly impacts a wide range of industries and influences many aspects of our daily lives. However, weather models often lack sufficient and reliable observations in the atmospheric boundary layer, which limits their accuracy, particularly in forecasting local weather phenomena over complex terrain. To fill this observational gap, Meteomatics has developed the Meteodrone-Meteobase-system.
Meteodrones are hexacopters equipped with meteorological sensors that collect high-resolution vertical profiles of temperature, humidity, wind speed and wind direction up to 6000 meters AMSL. The Meteobase acts as a base station, enabling the automatic launch and landing of the Meteodrones. Since 2020, Meteomatics has been operating a growing network of 3-10 Meteobase stations across Switzerland that is remotely controlled by a pilot. The data collected by the Meteodrones is automatically integrated into our high-resolution weather model EURO1k (1 km2 resolution), to close the observational gap and improve weather forecasts. Building on the success and experience gained from the Swiss network, Meteomatics will install and deploy a network of 30 Meteobase stations across Norway between 2024 and 2027.
Here we assess the quality of the Meteodrone measurements against the World Meteorological Organization's (WMO) observation requirements for high-resolution numerical weather prediction. Furthermore, we evaluate the impact of the Meteodrone data on forecasting local weather phenomena, such as stratus clouds, by comparing observations to model simulations with and without assimilated drone data. These findings showcase the operational capabilities of automatic Meteodrones for meteorological profiling and its contribution to improving numerical weather forecasts.
How to cite: Ramelli, F., Hammerschmidt, L., Guay, B., Kobras, M., Villinger, J. T., Rausch, J., Umek, L., and Fengler, M.: Improving weather forecasts through an operational network of Meteomatics Meteodrones, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15058, https://doi.org/10.5194/egusphere-egu25-15058, 2025.
The accurate identification and classification of wind structures in the atmospheric boundary layer (ABL) are promising to address the challenges of surface fluxes estimations and improving our understanding of the atmosphere dynamics. Traditionally, the Eddy-Covariance method is used to estimate those fluxes but it struggles to achieve the energy balance closure in specific atmospheric conditions such as day-time convective conditions. Those inaccuracies are possibly due to the presence of localized wind structures such as updrafts or other coherent structures in the vicinity of the measurement tower.
The present study was performed on numerical simulation databases to develop the methodology and will be applied to field data in the upcoming future.
First, an innovative framework that combines real-time data acquisition using unmanned aerial vehicle (UAVs) and signal reconstruction via Fourier mode decomposition is going to be presented. The UAV is flying on a predefined path to gather measurements that are then used to reconstruct the velocity field based on a limited number of Fourier modes. The solenoidal constraint is applied to the velocity field to get more accurate results. The determination of the Fourier modes is handled as a minimization problem while the limited number of modes ensures a good computational efficiency while trying to preserve the key features of the flow. The time-history of the measurements is considered up to a certain sample age but the location of the samples from the past is advected in a Lagrangian fashion according to the reconstructed field. This reconstruction process is performed in near real-time which is critical for practical applications.
Second, we will focus on the identification of the flow structures. It is handled by a neural network trained on an extensive data sets of more than 100 million samples taken from Large Eddy Simulations (LES) of convective boundary layer with various atmospheric conditions (mean Temperature going from 15 to 25°, geostrophic wind speed ranging from 0 to 4m/s...). This neural network has demonstrated good performance reaching an accuracy of 84% in structure identification according to the classification of Park et al. [1], even for ABL conditions unseen during the training process. These results showcase the robustness of the neural network and its ability to adapt to varying convective scenarios and its ability to identify various structures such as updrafts, downdraft and other coherent structures.
Finally, the two approaches are combined. Within a LES flow flied, a virtual UAV takes measurements on a predefined path, reconstructs the velocity field based on the Fourier modes approach and identifies the structures. The results of the identification problem are then compared to the actual features in the LES in order to evaluate the accuracy and effectiveness of the combined method.
[1] Park, S., P. Gentine, K. Schneider, and M. Farge, 2016: Coherent Structures in the Boundary and Cloud Layers: Role of Updrafts, Subsiding Shells, and Environmental Subsidence. J. Atmos. Sci., 73, 1789–1814, https://doi.org/10.1175/JAS-D-15-0240.1.
How to cite: Alsteens, L., Duponcheel, M., and Chatelain, P.: Real-time identification of flow structures in the atmospheric boundary layer using UAV-borne measurements and neural networks, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17032, https://doi.org/10.5194/egusphere-egu25-17032, 2025.
Uncrewed Aircraft Systems (UAS) have gained a strong presence in atmospheric sciences in recent years due to their flexibility, cost-effectiveness, and ability to access areas that are challenging for manned aircraft. As part of the #CHOPIN (CleanCloud Helmos OrograPhic Site ExperimeNt) campaign, the Unmanned Systems Research Laboratory (USRL) of the Cyprus Institute deployed UAS on Mt. Helmos, Greece, from October 11 to November 1, 2024, providing valuable data for the study of clouds.
The #CHOPIN campaign, conducted in collaboration with NCSR Demokritos and FORTH/EPFL, was hosted at the Kalavryta Ski Center with a base altitude for the UAS takeoffs and landings of 1690 m ASL. The campaign aimed to improve the understanding of aerosol-cloud interactions and to evaluate remote sensing algorithms and models. Located in a rapidly changing "climate hotspot" at the intersection of various air masses, Mount Helmos is particularly sensitive to environmental changes, with interactions between wildfire smoke, pollution, sea salt, and Saharan dust. This unique setting provides an ideal location to study the dynamics of aerosol-cloud interactions.
This study presents an overview of the UAS operations held at Mount Helmos, highlighting collection of vertical profiles of particle size distribution from the ground (1.7km ASL) up to 3.5 km ASL, both inside and outside the clouds. In contrast to point measurements from ground-based stations, UAS can follow cloud movement and sample the entirety of the cloud, capturing aerosol particle size distributions below, within, and above the clouds, and cloud droplet size-distributions. These measurements provide valuable insights into aerosol properties and cloud-aerosol interactions at different altitudes. Additionally, consecutive UAS flights helped study the evolution of the Boundary Layer Height (BLH) at the Helmos site. The data collected can fill the vertical resolution gap of aerosol size distributions and provide additional datasets for comparison with fixed station observations.
How to cite: Voss, A., Papetta, A., Marenco, F., Bezantakos, S., Goret, M., Håkansson, L., Michailidis, K., Biskos, G., Kezoudi, M., Mihalopoulos, N., and Sciare, J.: Cloud Sampling with UAS during the #CHOPIN Campaign at Mount Helmos in October 2024, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4415, https://doi.org/10.5194/egusphere-egu25-4415, 2025.
Airborne eddy-covariance measurements over the outer Mackenzie River delta in the western Canadian Arctic have linked significant methane (CH4) emissions to geological sources from subsurface reservoirs. However, few natural gas seeps have ever been mapped. Efforts by airborne imaging spectroscopy to locate these methane ‘hotspots’ primarily attributed higher emissions to biogenic CH4 from wetlands as a function of the water table. Resolving the discrepancies between these findings requires identifying seeps within areas of high background emissions. Conducting ground-based measurement surveys to achieve this is challenging in wetlands due to the impedance of widespread bodies of water and the risk of releasing CH4 when disturbing the soil during on-foot surveys.
To aid in identifying methane seeps that have not been mapped before, we present an ultra-lightweight in-situ methane sensor, and its deployment on a common commercially available Uncrewed Aerial Vehicle (UAV) – a DJI Matrice 300 RTK. This system was tested in a location in the Mackenzie River delta where CH4 is known to seep to the surface through conduits in thin, thawing permafrost overlying underground hydrocarbon reservoirs. The easily transportable UAV permits non-invasive, near-surface flight capabilities with highly flexible flight plans, while the sensor’s lightweight and power-efficient design permits high sensitivity for detecting and quantifying subtle variations in atmospheric CH4 concentrations, even in remote and challenging environments.
Our miniaturized, mid-infrared tunable diode laser absorption spectroscopy CH4 sensor targets CH4’s strongest rotational-vibrational transition at the 3270 nm wavelength. Employing the wavelength modulation technique and a small open-path gas absorption cell, the sensor is able to resolve atmospheric CH4 concentrations as low as 10 ppb (parts per billion) with a near-instantaneous response time (100 Hz sample rate) making it suitable for deployment on fast moving aerial platforms. The entire standalone instrument package weighs 1.2 kg and is ideal for integration on consumer UAVs which have limited payload capacities.
We flew the UAV in horizontal grid patterns typically used in source detection and localization scenarios, as well as vertical “curtain” patterns to sample cross sections of the CH4 plume arising from a known gas seep to quantify the flux rate. Preliminary data analysis using a Gaussian plume inversion technique yields a CH4 emission flux estimate near 8 kg hr-1, which is comparable to fugitive emissions from some oil and gas production facilities in Canada. Our results emphasize the significance of this approach to reliably, effectively, and precisely quantify CH4 emission from natural sources, as it will enable us to identify sources of CH4 hotspots and test our hypothesis that the magnitude and frequency of these emissions will increase throughout the study region as the climate warms.
How to cite: Norooz Oliaee, J., Beattie, M., MacLeod, R., Sun, C., Corbin, J., and Morse, P.: UAV-based measurement of natural gas seeps using a newly developed ultra-lightweight high-sensitivity methane sensor in the western Canadian Arctic, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20658, https://doi.org/10.5194/egusphere-egu25-20658, 2025.
Methane (CH₄) is a potent greenhouse gas, with a global warming potential 27.2 to 29.8 times greater than carbon dioxide (CO₂) over a 100-year timescale. Accurate quantification of methane emissions is crucial for developing effective climate change mitigation strategies and meeting international agreements on greenhouse gas reduction. However, significant uncertainties remain in estimating methane emissions, particularly from anthropogenic sources such as landfills, due to spatial heterogeneity and complex atmospheric interactions.
Landfills are known as significant contributors to anthropogenic methane emissions. In recent years, the use of unmanned aerial vehicles (UAVs) equipped with high-precision methane sensors has developed into a promising approach for quantifying these emissions. This method offers advantages such as improved spatial coverage, reduced operational costs and dynamic monitoring. The field of emissions quantification by UAV survey has rapidly expanded over the past decade, with a growing international academic community refining and validating methods, and an emerging commercial sector driving technological advancements.
Our study focuses on quantifying methane emissions from three UK landfills in 2024/25 using drone-based spatial sampling of in situ gas concentrations, wind speed and direction. We apply and compare different mass balance methods with varying approaches to spatial interpolation, to test the sensitivity of emission quantification to the selected approach. This analysis aims to assess the strengths and limitations of each method when applied to landfill environments. Additionally, we conduct an error analysis, examining the main sources of uncertainty such as wind measurements and background methane concentrations.
By addressing these challenges, our research contributes to improving the accuracy and robustness of drone-based methane quantification for landfill applications (and similar local scale sources). This work supports the development of methods for measuring emissions directly, which is crucial for setting emission reduction targets and improving national greenhouse gas inventories in waste management.
How to cite: Tsivlidou, M., McQuilkin, J., Ricketts, H., Wood, K., Yong, H., and Allen, G.: Quantifying methane emissions from UK Landfills Using Unmanned Aerial Vehicles, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9080, https://doi.org/10.5194/egusphere-egu25-9080, 2025.
Scanning Doppler wind lidars have become an important tool for investigating the kinematic structure of the mountain boundary layer and associated local flows. However, currently, no appropriate remote sensing technique exist that can capture the thermodynamic structure (temperature and humidity) in the lowest hectometres above ground at a sufficient spatiotemporal resolution. Hence, uncrewed aircraft systems (UAS) have become a prominent tool to fill this gap.
In this work, we report how a single off-the-shelf UAS (DJI Mini 2) equipped with a temperature and humidity logger (iMet-XQ2) can provide added value for the interpretation of Doppler wind lidar observations of complex winds in a narrow Alpine valley. The study site is located at Nafingalm, a mountain pasture located at the end of the Weer Valley in Tyrol, Austria. This location will be one of the target areas of the TEAMx Observational Campaign (TOC) in summer 2025. We present data from a short campaign conducted on 01 and 02 September 2023 to test the feasibility of combined UAS and Doppler lidar measurements at this remote site. The UAS performed vertical profiles over more than 24 hours of the lowest 120 m above ground at a 30-minute interval during daytime and an hourly interval during nighttime to capture the whole boundary layer evolution.
We will show the characteristics of daytime upvalley and nighttime downvalley winds as captured by the Doppler wind lidar and the corresponding temperature structure depicted by the UAS observations. In this context, the UAS measurements were crucial for correctly interpreting the transient warming phases during early evening as turbulent mixing events resulting from the interaction of a cross-mountain airflow with the stable boundary layer in the valley. The observations indicate that the early evening transition phase is characterized by high complexity and presents an interesting phase for studying turbulent processes in more detail within the framework of the TOC.
How to cite: Gohm, A.: Added value of off-the-shelf UAS for exploring Alpine valley flows, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4488, https://doi.org/10.5194/egusphere-egu25-4488, 2025.
This study demonstrates the feasibility of measuring temperature variance and sensible heat flux with self-calibrated fine-wire platinum resistance thermometers (FWPRT) on multicopter drones. The sensors are especially designed for light-weight, fast response-times and to be carried on miniature drones for turbulence measurements.
A significant improvement was found in vertical profiling of temperature gradients compared to slower solid-state sensors, demonstrating reduced hysteresis between ascent and descent phases and accurate representation of strong gradients.
More than 100 single flights with the sensors attached to drones of the SWUF-3D fleet were carried out in vicinity to a meteorological mast array at the WiValdi wind energy research park in Northern Germany. The comparison to sonic anemometers shows that mean temperature and temperature variance can be accurately measured within the background flow variability. The same applies for sensible heat flux, which was measured for the first time with multicopter UAS and the eddy covariance method. An uncertainty of 50 W m-2 was determined with the constraint that only low wind speed conditions could be used to guarantee accurate vertical wind speed measurements. The results indicate that the temperature sensors are suited for sensible heat flux measurements, but further improvements are necessary with regard to vertical wind speed estimates to decrease the overall uncertainty.
How to cite: Wildmann, N. and Györy, L.: Towards sensible heat flux measurements with multicopter UAS, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4779, https://doi.org/10.5194/egusphere-egu25-4779, 2025.
Uncrewed aerial vehicles (UAVs) are increasingly becoming complementary monitoring tools in various scientific fields, particularly in atmospheric and climate science, as they are versatile, relatively cheap, and can provide data at various spatial scales. However, UAV-based methodologies are still in their early stages and require extensive effort to fully exploit the potential of UAVs. Accurate quantification of emission rates from point or localized sources, such as geologic seeps or oil and gas production sites, is important for understanding emission processes and mitigating climate change. Conventional greenhouse gas monitoring platforms (i.e., flux chambers and eddy-covariance towers) have a significant sampling gap as they struggle to provide the spatial extent needed to accurately estimate emission rates from point or localized sources. UAV platforms carrying greenhouse gas analyzers for CO2 and CH4, along with an anemometer to measure 2D wind speed, air temperature, humidity, and pressure, allow capturing the spatial extent of a plume originating from a point source, and therefore accurately quantify its source strength.
The UAV platform employed for this study was used to sample a geological methane seep located in the Mackenzie Delta, Canada. Geological methane seeps can act as super emitters, releasing methane at rates significantly higher than typical biogenic sources; hence, accurate quantification of their emission rates is crucial to estimate the overall CH4 budget of the area. In July 2024, different flight strategies were tested to monitor point sources, including several curtain flights and a grid flight conducted at varying downwind distances from the seep. Using these flight data, the emission rate of the methane seep was quantified using two different methods: a mass-balance approach and a Gaussian plume inversion technique. The CH4 plume released from the seep showed concentrations about ten times higher than the atmospheric CH4 background levels, underscoring the significant potential impact of the geological seeps on the overall Arctic carbon budget.
How to cite: Bolek, A., Heimann, M., and Göckede, M.: UAV-based methodologies for quantifying methane emissions from point sources, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5595, https://doi.org/10.5194/egusphere-egu25-5595, 2025.
Since the Earth's energy balance is also influenced by aerosols and cloud droplets, knowledge concerning their size, number and vertical distribution is essential. To enable frequent, continuous, and cost-effective observations, a balloon-borne optical particle counter (“Universal Cloud and Aerosol Sounding System” (UCASS)) was developed by the University of Hertfordshire (UK). Hitherto, GPS or pressure-based measurements of the balloon’s ascent rate have been used to calculate the air’s flow velocity and volume flow rate through the UCASS, from which aerosol and cloud droplet concentrations were obtained. However, it appeared reasonable to modify the UCASS set-up by directly measuring the flow velocity in the immediate vicinity of the particle detection region within the UCASS with the aid of a thermal flow sensor (TFS), such that the volume flow within the UCASS can be measured continuously and in real time.
Consequently, a modification of the UCASS instrument has been conducted, including an internal TFS within the instrument for a more accurate determination of the probed (analyzed) air volume. This study shows that the TFS, located in a UCASS extending housing, has negligible influence on the flow velocity in the detection region within the UCASS. Field tests (in the framework of “TPChange”, DFG TRR301) have demonstrated that the ascent rates derived from GPS and pressure rarely match the TFS-based ascent rates and deviate by up to 30 %. Laboratory experiments show that with an isoaxial flow (between 2 and 8 m/s) towards the UACSS, the flow velocity within the UCASS is generally increased by ~11.3 % compared to the external flow velocity. Only if the angle of attack of the UCASS is changed to values between 20°-30°, the flow velocities within the UCASS correspond approximately to the external flow. In contrast to GPS and pressure-based ascent rates, the TFS-measured volume flow within the UCASS allows for obtaining true volume flow rates despite flow distortions (caused by the UCASS housing) and in particular the deflection of the UCASS body from an isoaxial orientation. In this way, the UCASS extension including the TFS represents an improvement of the UCASS measurements in the sense of more accurate recordings of volume flows and, thus, particle concentrations up to 7.5 km altitude.
How to cite: Jost, S., Weigel, R., Kandler, K., Valero, L., Girdwood, J., Stopford, C., Stanley, W., Eichhorn, L. K., von Glahn, C., and Tost, H.: Improving the accuracy of particle concentration measurements of an optical particle counter (UCASS) for balloon soundings, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9677, https://doi.org/10.5194/egusphere-egu25-9677, 2025.
Ultrafine aerosol particles (UFP, particles < 100 nm diameter) can contribute to respiratory and cardiovascular diseases. Aircraft engines have been found to emit significant amounts of UFP. The vertical and horizontal distribution of these particles in the vicinity of airports depends mainly on the wind speed, the local wind direction and the stability of the atmospheric boundary layer (ABL). To investigate the vertical distribution of UFP emissions depending on these parameters, TU Braunschweig conducted measurement flights with the uncrewed aerial system (UAS) ALADINA near the Berlin Brandenburg Airport (BER) in October 2021 during the ULTRAFLEB project and near the Frankfurt Airport (FRA) in October 2024 as part of the SOURCE FFR project.
During the two field campaigns, 140 and 110 vertical profiles were conducted at BER and FRA, respectively, at varying periods during the day. The results indicate that UFP concentrations are higher compared to the background conditions downwind of the airport plume. This behaviour can also be seen in the preliminary data analysis of the FRA campaign. During stable conditions of the ABL, the measured UFP remain within the inversion layer, as vertical mixing is suppressed. This is also the case for the relatively larger particles with a size diameter between 300 and 500 nm, which were mainly emitted from car traffic close to the site.
The UAS measurements performed downwind of FRA provide a profound understanding of the vertical distribution of UFP and the interaction with meteorological conditions will allow to relate this results to the in parallel performed particle dispersion and wake vortex modeling.
Acknowledgement:
This research is part of the project ULTRAFLEB (DE: Ultrafeinstaubbelastung durch Flughäfen in Berlin; EN: UFP caused by airports in Berlin) and is funded by the German Environment Agency (Umweltbundesamt) under grant RE FOPLAN FKZ 3720 52 201 0 and the work was carried out as part of the UFP exposure study SOURCE FFR (Study On Ultrafine Particles in the Frankfurt Airport Region) commissioned by the Umwelt und Nachbarschaftshaus (UNH).
How to cite: Bretschneider, L., Voß, A., Harm-Altstädter, B., Bärfuss, K., Käthner, R., Pätzold, F., Schlerf, A., Schuchard, M., Hermann, M., Winkler, U., and Lampert, A.: Using uncrewed aerial systems for investigating the vertical aerosol particle distribution close to German airports, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9787, https://doi.org/10.5194/egusphere-egu25-9787, 2025.
Uncrewed Aircraft Systems (UAS) are an invaluable tool for atmospheric profiling due to their mobility and capability to operate in the lower atmosphere and boundary layer. These regions represent an observational gap between ground-based stations and remote sensing instruments and satellites, which tend to be less accurate at lower altitudes. To fill this gap, while prioritising usability, versatility and safety, we have developed a custom meteorological sensor suite integrated into commercially available UAS, specifically multicopters.
The custom sensor package, called the Portable Aircraft Rucksack for Atmospheric Sensing and In-situ Turbulence Estimation (PARASITE), integrates data from the aircraft's positioning system and external meteorological sensors, including fast measurement of temperature, relative humidity and barometric pressure. We demonstrated the capabilities of this sensor package in flight on a DJI Mavic 3 multicopter with dimensions of 350 mm × 290 mm and a total take-off weight of 1 kg.
The three-dimensional wind vector is calculated using an improved method that combines a physical model based on meteorological and aircraft data - such as attitude, rotor frequencies, ground speed and air density - with machine learning techniques. The accuracy of the system was validated during the VITAL field campaign against ground-based in situ and remote sensing instruments, including Doppler wind lidars, differential absorption lidar, a 120 m meteorological tower and radiosondes.
The VITAL campaign was organised by the Hans-Ertel Centre for Weather Research of the German Weather Service (DWD) at Forschungszentrum Jülich, Germany in August 2024 and was also part of the World Meteorological Organisation's (WMO) global UAS Demonstration Campaign. During the campaign, PARASITE collected more than 100 vertical profiles, which were automatically transmitted wirelessly to a central data server after landing.
The system demonstrated compliance with WMO requirements by delivering processed data products in BUFR (Binary Universal Form for the Representation of Meteorological Data) format within minutes of each flight. The PARASITE system's rapid data processing and reliable performance highlight its potential to advance atmospheric profiling and support global meteorological initiatives.
How to cite: Büchau, Y., Schön, M., zum Berge, K., Gallatin, S., Bange, J., and Platis, A.: Enhancing High Resolution Atmospheric Profiling Using UAS: Deployment and Validation of the PARASITE Sensor Package, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11744, https://doi.org/10.5194/egusphere-egu25-11744, 2025.
Mineral dust, especially Saharan dust, has a significant impact on atmospheric processes by influencing radiative forcing and cloud formation. To improve the representation of dust events in numerical weather prediction models, high-resolution in-situ measurements are required. In this study, the MASC-3 unmanned aircraft system (UAS) was used to perform simultaneous vertical profiling of meteorological variables, turbulence, aerosol particles and space charge during an intense dust event over Cyprus in April 2022. The UAS, equipped with an optical particle counter payload (OPC-Pod), provided high-resolution measurements of aerosol number concentration, with observed peaks of 45 counts/ml at 2500 m above sea level (a.s.l.), consistent with concurrent remote sensing observations, satellite imagery and back-trajectory simulations, as well as measurements from other UAS. The space charge distribution within the dust layer showed distinct patterns at the upper and lower boundaries, consistent with theoretical expectations. This study demonstrates the capability of MASC-3 for simultaneous meteorological, aerosol and charge measurements at altitudes up to 5500 m, providing valuable data for improving dust transport models. The results highlight the value of in-situ observations with UAS in characterising the vertical structure and electrical properties of dust layers, contributing to a more accurate understanding of dust-atmosphere interactions.The measurements were part of a project supported by the European Commission under the Horizon 2020 - Research and Innovation Framework Programme, H2020-INFRADEV-2019-2, Grant Agreement number: 871115.
How to cite: Schön, M., Savvakis, V., Bramati, M., Platis, A., and Bange, J.: Combined measurement of Saharan dust, meteorological variables and space charge with the uncrewed aircraft system MASC-3 over Cyprus, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11881, https://doi.org/10.5194/egusphere-egu25-11881, 2025.
It is impossible to build measurement towers that are several kilometers high. Traditionally, aircraft have been used for atmospheric measurements. Due to their high true air speed, time-resolved measurements from manned aircraft are very challenging. This is especially true for measurements in clouds. Dropsondes and sounding balloons are regularly used to measure atmospheric profiles. However, it is not possible to measure the transport properties of moisture, temperature and aerosols. Unmanned aerial vehicles and drones can be used to measure atmospheric properties. However, due to either the high true air speed or the downwash from the propeller system, measurements of 3D wind speed are quite limited. In addition, the payload of these systems is modest. It is impossible to measure for many hours or days. It would therefore be desirable to have a system that can serve the same purpose as a tower, but can reach heights of several kilometers.
In this talk I will present the Max Planck Cloud Kite Observatory. It is a tethered helikite system operated from a winch on the ground or from a research vessel. The tether holding the helikite is made of very low weight, high or low density pre-stretched polyethylene. The helikite is both a helium balloon and a kite. By this it is not pushed towards the ground at high windspeeds nor does it fall to the ground when the wind stops. By mounting two 250m^3 helikites on top of each other, we achieved a safe lift of 150kg on the tether. Remotely operated instruments can be easily mounted anywhere on the tether. The system is certified for wind speeds up to 25m/s. Due to its stationary location it has shown to supplement measurements with UAVs perfectly. In addition multiple tethered helikite observatories can be employed in close vicinity to each other. In other words, the Max Planck Cloud Kite is a mobile observatory platform with the same utility as a multi kilometer high tower.
I will present the system: winch, helikite, mounting strategies, the helium recovery system and the instruments we have developed to measure eddy covariances, aerosols, and cloud particle dynamics by holographic particle image velocimetry. I will give an outlook on how such a system can be used to highly resolve stratocumulus clouds and other situations.
How to cite: Bodenschatz, E. and Bagheri, G.: Tethered Helikite Observatories, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14053, https://doi.org/10.5194/egusphere-egu25-14053, 2025.
Volcanic eruptions eject a large amount of aerosols and gases in the atmosphere with severe implications on the environment, climate and life on Earth and, in recent times, human society and aviation. Currently, the main technique for observing volcanic clouds relies on remote sensors both from satellites and ground observatories, also using multispectral cameras. However, the composition of volcanic clouds is difficult to assess due to physical limitations of the instruments’ detection capability: satellite and ground based remote sensing systems, generally used to detect and retrieve plume particles and gases, are limited by instrument sensitivity, spatial resolution and uncertainties of particles optical properties and size distribution. Moreover, the presence of high concentration of some gases in the atmosphere (e.g. CO2) makes their estimation impossible inside the volcanic cloud. Therefore, in-situ measurements are necessary to collect ground truth data to validate the remote sensing models and obtain an accurate characterization of a volcanic cloud.
Drone-mounted sensors could compromise the measurements within the plume due to the disturbances caused by the propellers. Additionally, the drone could be contaminated and damaged by the ash. As a less invasive and less expensive alternative, our groups at the Space Systems Laboratory of the University of Pisa together with INGV developed a novel method for in-situ measurements in volcanic clouds: a custom multi-gas sensor package (“Volcanosonde”) lifted by a tethered aerostat inside the plume. A volcanosonde is composed of a set of sensors, integrated on a circuit board, which record the concentrations of the main constituents of a volcanic plume (SO2, HCl, CO2, PM1 – 10) together with the atmospheric parameters (pressure, relative humidity and temperature). In the volcanosonde, data packets are acquired with a frequency of 1 Hz and stored onto an onboard memory, while a timewise subsampled subset of the data is transmitted to a ground station for real-time visualization via LoRa protocol over the 868 MHz ISM band.
We tested the developed apparatus during a measurement campaign in August 2024 on Mt. Etna, Sicily, in the frame of “VOLANDO”, a PRIN project funded by the European Union- Next Generation EU. The system consisted of a sounding balloon including three volcanosondes attached at 50 m intervals on the retaining rope, a stand-alone Optical Particle Counter and a GNSS receiver. The helium-inflated aerostat was raised to 400 m a.g.l. allowing the sondes to enter the plume and make uninterrupted measurements for 3 hours. The experiment was repeated on different days, effectively collecting in-situ data.
The system showed excellent flight behavior and was relatively easy to handle, even in no flat volcanic terrain, allowing for quick re-location of the flying balloon and the attached sondes over several areas of interest. Real time monitoring of the measurements provided the operators with indication of the quality of data collected and guided the right positioning of the flying platform so to achieve an optimal positioning of the volcanosondes within the plume. We estimate that a crew of two with minimal trraining can operate the tethered balloon autonomously under good weather conditions.
How to cite: Marcuccio, S., Corradini, S., Biondi, R., Ciancitto, F., Filippeschi, A., Giudice, G., Gemignani, M., Guerrieri, L., Lambertucci, L., Marsili, I., Merucci, L., Naranjo, C., Scollo, S., and Stelitano, D.: A multi-gas sensor system lifted by a tethered aerostat for real time in-situ investigation of volcanic plumes, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19551, https://doi.org/10.5194/egusphere-egu25-19551, 2025.
Using a drone-based method for simultaneous flux measurements of greenhouse gases (GHGs) we assessed methane (CH4) and nitrous oxide (N2O) at several wastewater treatment plants (WWTPs) with anaerobic digestion. Results showed unexpectedly high fluxes and discovered that N2O emissions from sludge storage are at least as important as CH4 emissions in terms of global warming. Despite this, N2O emissions from anaerobic digestion sludge are usually assumed to be negligible and therefore not measured routinely at WWTPs. The CO2-equivalent total emissions of CH4 and N2O were 3-fold higher than the IPCC-recommended emission-factor-based estimates. The drone-method works in a wide variety of environments for simultaneous measurements of the major GHG fluxes (CH4, N2O, and CO2) without the need to do repeated flight patterns to cover all gases, alleviating the problem of flux potentially changing between flights which would otherwise make flux comparisons between the different GHGs less reliable.
The drone method used is a further developed version of our previous method (Gålfalk et al 2021 - https://pubs.acs.org/doi/10.1021/acsearthspacechem.1c00106) with longer flight time, higher payload, all major GHGs measured simultaneously, improved logging with all measurements needed for flux calculations being measured on-board the drone without any need for ground-based auxiliary measurements, and more convenient post-processing to calculate fluxes.
How to cite: Gålfalk, M. and Bastviken, D.: Greenhouse gas emissions from wastewater treatment plants using drone-based measurements, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19785, https://doi.org/10.5194/egusphere-egu25-19785, 2025.
Uncrewed Aircraft Systems (UAS) are by now established platforms for measurements in volcanic plumes. Trace gases of interest range from sulfur dioxide and halogenated substances to carbonaceous trace gases including carbon monoxide (CO) and carbon dioxide (CO2). However, sophisticated measurement techniques for high-precision observations of trace gases often require instrumentation that cannot be used on board UAS due to the high weight and power consumption of the devices
Originally developed for stratospheric observations, air sampling with long coiled tubes in AirCores, has proven to be a light-weight sampling technique to probe parts of the atmosphere that are otherwise difficult to access. Trace gas analysis of sampled air is done post-flight, most commonly with fast high-precision optical methods, delivering high-quality and high-resolution trace gas mixing ratios. While balloon-borne AirCore setups perform so-called passive sampling, making use of natural pressure differences, in 2018, a team at Groningen University developed a UAS-deployable small active AirCore device collecting air with a small pump.
In July 2024, we deployed this AirCore setup on a UAS to probe the volcanic plume of Mt. Etna (Sicily, Italy), which was particularly active at the time of the measurements. This was to our knowledge the first time that the AirCore sampling technique was used to sample air inside a volcanic plume. The air sample was successfully analysed with cavity-ring down spectroscopy for CO, CO2 and methane (CH4). While CO and CO2 mixing ratios were markedly enhanced in the plume and signals correlated well with SO2 enhancements observed by an electro-chemical sensor, no significant enhancement of CH4 was observed. The observed trace gas mixing ratios will be used in further studies to model the chemistry in the plume of Mt. Etna.
How to cite: Schuck, T., Degen, J., Bobrowski, N., Bossard, M., Boucher, L., Chen, H., Geil, B., Giuffrida, G., van Heuven, S., Hoffmann, T., Ortenzi, G., and Engel, A.: First deployment of a drone-borne active AirCore in a volcanic plume at Mount Etna, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1266, https://doi.org/10.5194/egusphere-egu25-1266, 2025.
Posters virtual: Tue, 29 Apr, 14:00–15:45 | vPoster spot 5
EGU25-5789 | Posters virtual | VPS2
Lessons learned from a UAS survey of methane emissions from multiple biogas plants in FranceTue, 29 Apr, 14:00–15:45 (CEST) | vP5.21
An on-going campaign monitors the greenhouse gases emissions of biogas plants in the Grand Est region, in France, using airborne in situ CO2 and CH4 concentrations and wind measurements from Uncrewed Aerial System, associated with a mass balance method. During 16 days in 2024, we quantified the instantaneous emissions of 19 agricultural biogas plants, with installed methane productions ranging from 128 to 312 Nm3.h-1,producing biogas injected into the network mainly from manure, energy crops and agricultural wastes.
Observations obtained to date were used to quantify emissions either representative of the globality of a biogas plant or of specific targeted sources inside a site (inputs, effluents, digesters or biogas purification). Global plant methane emissions among all sites range from 1.5 to 26 kg.h-1, with average emissions of 10 kg.h-1. Repeated measurements of emissions on the same site at different dates depict a significant temporal variability, however overwhelmed by the variability of emissions among all sites. We estimated instantaneous methane losses ranging from 1.7 to 10 %, comparing monitored emissions with the installed productions. Emissions of targeted sources among sites suggest that inputs and effluents might be the predominant methane sources on the sites, while biogenic CO2 emissions might be mostly attributed to the biogas purification process.
This campaign highlighted several limits intrinsically linked with the mass balance method. One of them is the sensitivity to contamination by parasite sources, which has to be anticipated during the field campaign preparation. Another difficulty is the risk of measuring truncated plumes, as the mass balance method requires the monitoring of an entire plume cross-section to provide quantifications representative of the complete source emissions. These limitations could be overturned in the future by alternative quantification methods, such as inversion methods based on Large Eddy Simulation of the atmospheric transport, considering the highly variable nature of the turbulent plume. These new developments, associated with evolutions of the monitoring protocol, may improve the reliability and precision of the results.
How to cite: Bonne, J.-L., Dumelie, N., Lauvaux, T., Abdallah, C., Burgalat, J., Albora, G., Vincent, J., Cousin, J., Parent, F., Moncourtois, V., and Joly, L.: Lessons learned from a UAS survey of methane emissions from multiple biogas plants in France, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5789, https://doi.org/10.5194/egusphere-egu25-5789, 2025.
