AS1.37
Orals: Wed, 26 Apr | Room M1
The European Space Agency (ESA)’s wind mission, Aeolus, was launched on 22 August 2018. It is a member of the ESA Earth Explorer family and its main objective is to demonstrate the potential of Doppler wind Lidars in space for improving weather forecast and to understand the role of atmospheric dynamics in climate variability. Aeolus carries a single instrument called ALADIN: a high sophisticated spectral resolution Doppler wind Lidar which operates at 355 which is the first of its kind to be flown in space.
Aeolus provides profiles of single horizontal line-of-sight winds (primary product) in near-real-time (NRT), and profiles of atmospheric backscatter and extinction. The instrument samples the atmosphere from about 30 km down to the Earth’s surface, or down to optically thick clouds. The required precision of the wind observations is 1-2.5 m/s in the troposphere and 3-5 m/s in the stratosphere while the systematic error requirement be less than 0.7 m/s. The mission spin-off product includes information about aerosol and cloud layers. The satellite flies in a polar dusk/dawn orbit (6 am/pm local time), providing ~16 orbits per 24 hours with an orbit repeat cycle of 7 days. Global scientific payload data acquisition is guaranteed with the combined usage of Svalbard and Troll X-band receiving stations.
After almost five years in orbit and despite some performance issues related to its instrument ALADIN, Aeolus has achieved all its scientific objectives and gone beyond its original designed life-time in space. Positive impact on the weather forecast has been demonstrated by multiple NWP centres world-wide, with four European meteorological centres now are assimilating Aeolus winds operationally, paving the way to its successor: EPS-Aeolus. Aeolus data is being used with success over a number of innovative research streams with growing scientific impact on literature.
The status of the Aeolus mission will be presented including the last main challenge to re-enter the satellite from space with an assisted scenario instead of an uncontrolled one, as initially foreseen by design.
How to cite: Parrinello, T., Wernham, D., Fehr, T., Von Bismarck, J., Tran, V. D., Romanazzo, M., Candra Krisna, T., Sathe, A., Bickerton, P., Krisch, I., and Rennie, M.: Aeolus: ESA’s wind mission. Status and future challenges , EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-3490, https://doi.org/10.5194/egusphere-egu23-3490, 2023.
The German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt, DLR) conducted four airborne campaigns for the validation of the Aeolus L2B wind product during the first three years of ESA’s wind lidar mission between 2018 and 2021. After three campaigns in Europe, the Aeolus VAlidation Through Airborne LidaRs in the Tropics (AVATAR-T) campaign was performed around the Cabo Verde archipelago in September 2021 as part of the Joint Aeolus Tropical Atlantic Campaign (JATAC). AVATAR-T employed the DLR Falcon aircraft which carried two Doppler wind lidar (DWL) instruments: the heterodyne-detection 2-µm DWL acting as a high-accuracy reference and the ALADIN Airborne Demonstrator (A2D), representing a prototype of the direct-detection DWL on-board Aeolus with a high degree of commonality in terms of design and measurement principle.
In the framework of AVATAR-T, 11 coordinated flights along the Aeolus track were performed covering nearly 11,000 km of the satellite's measurement swath. The research flights yielded a comprehensive set of A2D and 2-µm DWL wind observations to validate the Aeolus wind product under the influence of the Saharan Air Layer (SAL), the African Easterly Jet, the Subtropical Jet and the Intertropical Convergence Zone. In particular, the campaign results give insight into the impact of atmospheric aerosols onto the operational Rayleigh-clear and Mie-cloudy horizontal line-of-sight (HLOS) winds regarding potential errors that arise from crosstalk between the two complementary receiver channels and their respective wind data coverage in the troposphere.
Validation of the Aeolus wind product based on 2-µm DWL data shows that the systematic error almost fulfills the mission requirement of being below 0.7 m/s (HLOS) for both Rayleigh-clear and Mie-cloudy winds. The random error, however, is larger than specified (2.5 m/s HLOS), being close to 3 m/s for Mie-cloudy winds and as high as 7 m/s for Rayleigh-clear winds. A more detailed investigation reveals that the Rayleigh-clear random error is increased at lower altitudes in case of signal extinction due to aerosols.
The collocated A2D wind observations provide valuable information on the potential optimization of the Aeolus wind retrieval and related quality control (QC) algorithms. For instance, the A2D, unlike ALADIN, delivered a broad vertical and horizontal coverage of Mie winds across the SAL, whereas A2D Rayleigh winds measured in this region, which are affected by Mie contamination through crosstalk and signal extinction, are effectively filtered out. Preliminary studies suggest that a refinement of the Aeolus wind retrieval may improve the Mie wind data coverage in aerosol regions.
In addition, we studied the influence of different QC schemes on the validation results and developed a two-step QC approach that ensures effective outlier removal and compliance with the Aeolus mission requirements document. The QC scheme also improves the comparability of different validation studies and thus helps to facilitate the consolidation of the Aeolus error evaluation from different Cal/Val teams.
The contribution presents comparative wind observations of Aeolus and the two DLR airborne wind lidar instruments from the JATAC with a focus on the error assessment and a potential improvement of the Aeolus wind data product.
How to cite: Lux, O., Witschas, B., Lemmerz, C., Weiler, F., Marksteiner, U., Rahm, S., Geiß, A., Schäfler, A., Rennie, M., and Reitebuch, O.: Validation of the Aeolus wind observations in the tropics using the ALADIN Airborne Demonstrator and 2-µm Doppler wind lidar, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-1355, https://doi.org/10.5194/egusphere-egu23-1355, 2023.
In the framework of the Joint Aeolus Tropical Atlantic Campaign (JATAC), a temporary ground-based ACTRIS aerosol remote sensing station has been setup by TROPOS at the Ocean Science Center Mindelo (OSCM) in June 2021. The instrumental capabilities for aerosol profiling at the OSCM comprise a multiwavelength-Raman-polarization lidar Polly XT and an AERONET sun photometer. Furthermore, a scanning HALO photonics Doppler lidar is utilized to study the dynamics near the observational site. Continuous 24/7 observations have been performed since June 2021, thus covering the four intensive observational periods of JATAC (July 2021, September 2021, June 2022, September 2022).
In this presentation, we want to discuss the capabilities of Aeolus to observe the aerosol conditions including the Saharan dust layer (SAL) above the Cabo Verdean islands. The time series of the ground-based PollyXT lidar from June 2021 until today has shown, that dust is omnipresent above the local boundary layer in the summer months. The maximum dust layer top height has been observed in July with 7 km. The SAL top height has then decreased to 3 km in November. Some rainy periods were observed in September/October, especially in the year 2022 for the fourth intensive JATAC campaign.
We will utilize the direct Aeolus overpasses over Mindelo each Friday during these four periods (and for other seasons) to make a long(er)-term assessment of the Aeolus aerosol capabilities (L2A) involving also products from the most recent algorithm versions (Baselines). Due to the capabilities of the ground-based PollyXT lidar, we can directly compare the 2 main products of Aeolus: The extinction coefficient and the co-polar backscatter coefficient. Doing so, we can also quantify the influence of the missing polarization component in the Aeolus aerosol products which is important for the planning of the potential Aeolus follow-on mission, for which the polarization capabilities are still under discussion.
Finally, the lessons learnt from the current Aeolus Cal/Val on Cabo Verde can be also used for the upcoming EarthCARE mission as TROPOS has started to setup a permanent ACTRIS aerosol and cloud remote sensing supersite at Mindelo.
How to cite: Baars, H., Gebauer, H., Floutsi, A., Trapon, D., Bley, S., Althausen, D., Engelmann, R., Skupin, A., Radenz, M., Ansmann, A., Klamt, A., Heese, B., Wandinger, U., Silva, E., Rodrigues, E., Silva, P., Zenk, C., Paschou, P., and Marinou, E.: Quality assessment of Aeolus L2A products at Cabo Verde during JATAC and beyond - validation with ground-based lidar observations, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-5631, https://doi.org/10.5194/egusphere-egu23-5631, 2023.
|
How to cite: Flamant, C. and the CADDIWA Team: Cyclogenesis in the tropical Atlantic: First scientific highlights from the Clouds-Atmospheric Dynamics-Dust Interactions in West Africa (CADDIWA) field campaign, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-1153, https://doi.org/10.5194/egusphere-egu23-1153, 2023.
Massive amounts of desert dust uplifted over the Sahara are exported over the North Atlantic. They play a major environmental role over this region, impacting the Earth radiative budget, atmospheric dynamics and thermodynamics, cloud properties, atmospheric composition, and biogeochemistry. These multiple impacts of Saharan dust can also affect the evolution of mesoscale convective systems (MCS) formed over West Africa that may lead to the formation of tropical cyclones over the North Atlantic. A better understanding of these aspects, also influenced by African Easterly waves, is the primary objective of the “Clouds-Atmospheric Dynamics-Dust Interactions in West Africa - CADDIWA ” field experiment that took place on September 2021.
The current presentation will provide a comprehensive description of the three-dimensional (3D) distribution of Saharan dust and its pathways of export over the North Atlantic during CADDIWA. This will be analysed with respect to the location and evolution of the MCS travelling over the region. This characterisation will be done using a suite of observations which will be compared with dust simulations. The objective is to analyse the difference in terms of abundance and 3D distribution of dust between the cases where MCSs lead to cyclogenesis and those not evolving that way.
The ensemble of datasets describing the Saharan dust distribution will be inter-compared and their consistency verified. Twice-daily satellite thermal infrared hyperspectral measurements from IASI will be used to document the 3D distribution of desert dust for cloud-free conditions using the AEROIASI approach (Cuesta et al., 2015; 2020). Further details will be provided by nadir-pointing lidar measurements from AEOLUS and CALIOP space sensors, and from the RALI airborne instruments, in terms of transects of aerosol profiles and winds. In addition to aerosol backscatter profiles, AEOLUS and LNG-RALI will provide aerosol extinction profiles, provided their high spectral resolution capabilities. Observations from MODIS and VIIRS of aerosol optical depth will inform on the horizontal distribution of desert dust. Airborne in situ measurements of the size distribution and intensive optical properties of desert dust, such as the angstrom exponent, will be compared to those used as a priori properties of dust within the satellite dust retrievals (particularly for IASI). These satellite and airborne measurements will be confronted with simulations from the Meso-NH and WRF-CHIMERE, contributing with an all-sky and hourly 3D description.
How to cite: Cuesta, J., Flamant, C., Gaetani, M., Delanoë, J., Chaboureau, J.-P., Menut, L., and Formenti, P.: Three-dimensional pathways of Saharan dust export over the North Atlantic during the CADDIWA field campaign, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-10020, https://doi.org/10.5194/egusphere-egu23-10020, 2023.
In the framework of the Joint Aeolus Tropical Atlantic Campaign (JATAC), the ASKOS experiment was implemented in Cabo Verde during summer and autumn of 2021 and 2022. The main objective of ASKOS was the collection of an unprecedented dataset of synergistic measurements in the region, to be used to address a wide range of scientific objectives, namely the support of the validation of Aeolus mission’s products, the study of the processes affecting dessert dust transport (water vapor, giant particles, mixing with boundary layer dynamics), the characterization of the cloud microphysics, the effect of dust particles in the cloud formation over the region, the effect of the large dust particles on radiation and others.
During the ASKOS experiment, intense ground-based remote sensing and airborne in situ measurements took place on and above Mindelo on the island of São Vicente, Cabo Verde. At the Ocean Science Center in Mindelo (OSCM), a full ACTRIS remote sensing super site was set up in 2021, including a multiwavelength-Raman-polarization lidar PollyXT, an AERONET sun photometer, a Scanning Doppler wind lidar, a microwave radiometer and a cloud radar belonging to ESA fiducial reference network (FRM4Radar). Additionally, the ESA’s reference lidar system eVe, a combined linear/circular polarization lidar with Raman capabilities, was deployed. In 2022, the operations were enhanced with the deployment of airborne in-situ aerosol measurements on-board UAVs deployed by the Cyprus Institute, solar radiation measurements supported by PMOD/WRC, dust particle orientation measurements from the WALL-E lidar of National Observatory of Athens, and radiosonde releases equipped with additional electric field and electric charge measurements. The campaign was supported by dedicated numerical weather and dust simulations from CAMS and ECMWF, and tailored WRF simulations with nested domains above the campaign site.
From the ASKOS dataset, three cases have been selected as "golden cases” where multiple JATAC airborne platforms and Aeolus satellite performed collocated measurements alongside with the ground-based instrumentation around the ASKOS operations site. Furthermore, multiple synergistic measurements with the JATAC airborne platforms were performed in the broader Cabo Verde region. Here, we quickly introduce ASKOS measurements and present first results.
How to cite: Marinou, E., Amiridis, V., Paschou, P., Tsikoudi, I., Tsekeri, A., Daskalopoulou, V., Baars, H., Floutsi, A., Kouklaki, D., Pirloaga, R., Marenco, F., Kazoudi, M., O Connor, E., Pfitzenmaier, L., Zenk, C., Ryder, C., Von Bismarck, J., and Fehr, T. and the ASKOS team: ASKOS Campaign 2021/2022: Overview of measurements and applications, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-16530, https://doi.org/10.5194/egusphere-egu23-16530, 2023.
The ASKOS experimental campaign of European Space Agency (ESA) was organised by the National Observatory of Athens, and aimed at the calibration and validation of the Aeolus satellite aerosol/cloud product. Airborne observations were performed by the Climate and Atmosphere Research Centre (CARE-C) team of the Cyprus Institute at the Cesaria Evora International Airport of the island of São Vicente in Cape Verde between 10 and 30 June 2022. These in-situ aerosol measurements were conducted using the advanced Unmanned Aerial Vehicles (UAVs) of the Unmanned System Research Laboratory (USRL), equipped with specialised aerosol in-situ sensors, capturing the Saharan Air Layer (SAL) from ground up to 5.3 km Above Sea Level (ASL). The new custom-designed Composite Bird (CoBi) USRL and Skywalker UAVs (Kezoudi et al., 2021), were equipped with Optical Particle Counters (OPCs), samplers and backscatter sondes.
25 UAV vertical flights were performed in total, with 11 of them during night. The altitude of the Marine Boundary Layer (MBL) was mainly observed from ground up to about 1.0 km ASL, whereas during most of the flights, high concentrations of dust particles were found between 1.5 and 5.0 km ASL. Results obtained from OPCs show the presence of particles sizing up to 20 um within MBL and up to 40 um within SAL. Further information on morphology and mineralogy of observed particles will be given by the offline analysis of collected samples under Scanning Electron Microscope (SEM). COBALD observations alongside ground-based lidar measurements agree on the presence of non-spherical particles within dust layers.
Ongoing exploitation of airborne observations along with coincident and collocated ground-based measurements will provide a complete picture for comparison with Aeolus data, particularly in relation to aerosols, where we have the most to learn.
How to cite: Kezoudi, M., Marenco, F., Papetta, A., Keleshis, C., Ryder, C., Kandler, K., Girdwood, J., Stopford, C., Wienhold, F., Gao, R.-S., Marinou, E., Amiridis, V., Mocnik, G., Baars, H., and Sciare, J.: Profiling Saharan Airborne Dust with UAV-based in-situ Instrumentation during the ASKOS Experiment in Cape Verde, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-17090, https://doi.org/10.5194/egusphere-egu23-17090, 2023.
The JATAC campaign in September 2021 and September 2022 on and above Cape Verde Islands have resulted in a large dataset of in-situ and remote measurements. In addition to the calibration/validation of the ESA’s Aeolus ALADIN during the campaign, the campaign also featured secondary scientific objectives related to climate change. The atmosphere above the Atlantic Ocean off the coast of West Africa is ideal for the study of the Saharan Aerosol layer (SAL), the long-range transport of dust, and the regional influence of SAL aerosols on the climate.
We have instrumented a light aircraft (Advantic WT-10) with instrumentation for the in-situ aerosol characterization. Ten flights were conducted over the Atlantic Ocean up to over 3000 m above sea level during two intense dust transport events. PollyXT, and EvE lidars were deployed at the Ocean Science Center, measuring the vertical optical properties of aerosols and were also used to plan the flights.
The particle light absorption coefficient was determined at three different wavelengths with Continuous Light Absorption Photometers (CLAP). They were calibrated with the dual wavelength photo-thermal interferometric measurement of the aerosol light-absorption coefficient in the laboratory. The particle size distributions above 0.3 µm diameter were measured with two Grimm 11-D Optical Particle Size Spectrometers (OPSS). These measurements were conducted separately for the fine aerosol fraction and the enriched coarse fraction using an isokinetic inlet and a pseudo-virtual impactor, respectively.
The aerosol light scattering and backscattering coefficients were measured with an Ecotech Aurora 4000 nephelometer. The instrument used a separate isokinetic inlet and was calibrated prior to and its calibration validated after the campaign with CO2. We have measured the total and diffuse solar irradiance with a DeltaT SPN1 pyranometer. CO2 concentration, temperature, aircraft GPS position altitude, air and ground speed were also measured.
The in-situ single-scattering albedo Angstrom exponent and the lidar depolarization ratio will be compared as two independent parameters indicating the presence of Saharan dust. We will show differences between homogeneous Saharan dust layer in space (horizontally and vertically) and time and events featuring strong horizontal gradients in aerosol composition and concentration, and layering in the vertical direction. These layers often less than 100 m thick, separated by layers of air with no dust.
Complex mixtures of aerosols in the outflow of Saharan dust over the Atlantic Ocean in the tropics will be characterized. We will show the in-situ atmospheric heating/cooling rate and provide insight into the regional and local effects of this heating of the dust layers. These measurements will support of the research on evolution, dynamics, and predictability of tropical weather systems and provide input into and verification of the climate models.
How to cite: Yus Díez, J., Bervida, M., Drinovec, L., Žibert, B., Lenarčič, M., Marinou, E., Paschou, P., Siomos, N., Baars, H., Engelmann, R., Skupin, A., Zenk, C., Fehr, T., and Močnik, G.: Airborne In-situ Measurements during JATAC/CAVA-AW 2021/2022 campaigns - First Climate-Relevant Results, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-15901, https://doi.org/10.5194/egusphere-egu23-15901, 2023.
Tropical convection is a key player in the global weather and climate. Observing and predicting convective initiation, growth, dissipation, and interactions with the environment over the tropical ocean remain a grand challenge. The science objectives of CPEX-AW are: 1) better understanding interactions of convective cloud systems and tropospheric winds as part of the joint NASA-ESA Aeolus Cal/Val - Joint Aeolus Tropical Atlantic Campaign (JATAC), 2) observing the vertical structure and variability of the marine boundary layer in relation to initiation and lifecycle of the convective cloud systems, convective processes (e.g., cold pools), and environmental conditions within and across the ITCZ, 3) investigating how the African easterly waves and dry air and dust associated with Sahara Air Layer control the convectively suppressed and active periods of the ITCZ, and 4) investigating interactions of wind, aerosol, clouds, and precipitation and effects on long range dust transport and air quality over the western Atlantic. The CPEX-AW science team and the NASA DC-8 aircraft were deployed to St. Croix, the US Virgin Islands, from 18 August–10 September 2021, to address the science objectives. DC-8 is equipped with the Doppler Aerosol Wind Lidar (DAWN), Airborne Precipitation and Cloud Radar 3rd Generation (APR-3), High Altitude Lidar Observatory (HALO) Water Vapor DIAL and HSRL, High Altitude Microwave Sounding Radiometer (HAMSR), and GPS dropsondes. This article provides a summary of CPEX-AW scientific discoveries with highlights from some key aspects: a unique virtual campaign during the COVID pandemic and outstanding airborne observations from the field campaign.
- More than 120 researchers including graduate students and postdocs participated in CPEX-AW in St. Croix, Puerto Rico, and remotely.
- We have flown seven research missions that collected unprecedented data from DAWN, HALO, APR-3, HAMSR, and dropsondes, in a wide arrange of conditions from strong dust outbreak events to tropical storms.
- Underflown six Aeolus overpasses for a total of 5,836 km, which provide valuable data sets for Aeolus Cal/Val and studies of impact on weather forecasting.
- Complex wind and convection in pre-Tropical Storm (TS) Ida and Ida over the Gulf of Mexico before the major Hurricane Ida made landfall, long lasting TS Kate and its interaction with dust and dry air over the central Atlantic, and dry air intrusion in Hurricane Larry.
- Co-located boundary layer observations over saildrones that measure air-sea fluxes and ocean current data in collaboration with the NOAA field campaign.
How to cite: Chen, S., Mazza, E., Savarin, A., Kerns, B., Zipser, E., Hristova-Veleva, S., Sy, O., Tanelli, S., Su, H., Kavaya, M., Nehrir, A., Pu, Z., and Skofronick-Jackson, G.: Convective Processes Experiment – Aerosol and Winds (CPEX-AW): Virtual and Field Campaigns, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-5067, https://doi.org/10.5194/egusphere-egu23-5067, 2023.
The 2022 Convective Processes Experiment – Cabo Verde (CPEX-CV) collected observations using the NASA DC-8 to study dynamics and microphysics related to the Saharan Air Layer (SAL), African easterly waves and jets, and deep convection within the Intertropical Convergence Zone (ITCZ) in the tropical East Atlantic. CPEX-CV measurements also collected data to help calibrate and validate ESA’s Aeolus Doppler wind lidar. CPEX-CV is part of combined effort with the European Space Agency (ESA) and their partner laboratories and universities called the Joint Aeolus Tropical Atlantic Campaign (JATAC) to validate ESA’s Aeolus satellite. As part of the CPEX-CV – JATAC collaboration from Cabo Verde in September 2022, the NASA DC-8, outfitted with a comprehensive suite of remote and in-situ sensors, coordinated with the ASKOS ground site at Mindelo and the Slovenian WT-10 aircraft to validate AEOLUS wind and aerosol products as well as to link quantitatve aerosol observations from multiple vantage points to better understand the role of the SAL in toprical dynamics.
During CPEX-CV the NASA DC-8 was outfitted with the Advanced Vertical Atmospheric Profiling System (AVAPS) dropsondes, Doppler Aerosol Wind Lidar (DAWN), High-Altitude Lidar Observatory (HALO), third generation Airborne Precipitation Radar (APR-3), High-Altitude Monolithic Microwave Integrated Circuit Sounding Radiometer (HAMSR), and the Cloud Aerosol and Precipitation Spectrometer. This presentation will highlight the HALO water vapor DIAL and aerosol/cloud HSRL observations collected during CPEX-CV and discuss the synergies with the JATAC campaign. HALO HSRL observations are compared and contrasted with those taken from the ground site at Mindelo to better understand the influence of orographic island effects on the transport of aerosols and better constrain aerosol processes such as aerosol electrification being studied by ASKOS. Additionally, HALO aerosol backscatter, depolarization, and extinction products at 532 nm and 1064 nm are used to evaluate Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) aerosol retrievals at those same wavelengths and, after adjustment to 355 nm, are compared against Aeolus backscatter and extinction products. Areas for future collaborative efforts will also be discussed including Aeolus and Earthcare validation.
How to cite: Nehrir, A., Ferrare, R., Collins, J., Grimley, R.-B., Crosbie, E., and Marinou, E.: Overview of the High Altitude Lidar Observatory (HALO) water vapor DIAL and High Spectral Resolution Lidar observations during the summer 2022 CPEX-CV Campaign, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-17250, https://doi.org/10.5194/egusphere-egu23-17250, 2023.
Posters on site: Wed, 26 Apr, 16:15–18:00 | Hall X5
ESA’s Aeolus satellite observations are expected to have the biggest impact for the improvement of numerical weather prediction in the Tropics. An important case relating to the predictability of tropical weather systems is the outflow of Saharan dust, its interaction with cloud microphysics and impact on the development of tropical storms over the Atlantic Ocean.
The Joint Aeolus Tropical Atlantic Campaign (JATAC) deployed on Cabo Verde (2021/2022) and the US Virgin Islands (2021) supported the validation and preparation of the ESA missions Aeolus, EarthCARE and WIVERN, and addressed science objectives regarding the Saharan Aerosol layer, African Easterly Waves and Jet, Tropical Easterly Jet, and the Intertropical Convergence Zone, as well as their relation to the formation of convective systems, and the long-range transport of dust and its impact on air quality.
JATAC started in July 2021 with the deployment of ground-based instruments in the frame of the ASKOS project at the Ocean Science Center Mindelo, including the eVe and PollyXT lidars, and a W-band Doppler cloud radar. By mid-August, the CPEX-AW campaign started operations from the US Virgin Islands with NASA’s DC-8 flying laboratory in the Western Tropical Atlantic and Caribbean carrying the Doppler Aerosol Wind Lidar (DAWN), Airborne Precipitation and Cloud Radar (APR-3), Water Vapor DIAL and HSRL (HALO), microwave sounder (HAMSR) and dropsondes. In September the DLR Falcon-20 aircraft, carrying the ALADIN Airborne Demonstrator (A2D) and the 2-µm Doppler wind lidar, and the Safire Falcon-20, carrying the high-spectral-resolution Doppler lidar (LNG), the RASTA Doppler cloud radar, in-situ cloud and aerosol instruments, and dropsondes, were deployed to Sal in the frame of the AVATAR-T and CADDIWA projects. The Aerovizija Advantic WT-10 light aircraft with optical particle spectrometers, filter-photometers and nephelometers for in-situ aerosol characterisation was operating in close coordination with the ground-based observations in the CAVA-AW project.
The activities continued in June 2022 when the ASKOS ground based observations were enhanced with UAV airborne in-situ aerosol measurements deployed by the Cyprus Institute, solar radiation measurements supported by PMOD/WRC, dust particle orientation measurements (WALL-E lidar), and radiosonde releases equipped with electric field-mills. NASA deployed the DC-8 aircraft all September to Sal with the 2021 payload in the framework of the CPEX-CV activity, including regular radiosonde launches. As in 2021, the Aerovizija aircraft took part with in-situ aerosol measurements during two weeks in September. JATAC was supported by dedicated numerical weather and dust simulations supporting forecasting efforts and addressing open science questions.
Around 60 scientific flights of four aircraft, with an additional 25 UAV flights, were performed during JATAC. 23 Aeolus orbits were underflown, many of them with simultaneous observations of multiple aircraft collocated with ground-based observations. In addition, the science objectives were fully covered through the large number of flights, ground based cloud and aerosol observations, regular radiosondes and dropsondes.
Overall, JATAC activities have resulted in a high-quality and comprehensive dataset supporting a wide range of tropical atmospheric research, the validation of Aeolus and other satellites, and have provided key reference data for the development future Earth Observation missions.
How to cite: Fehr, T., McCarthy, W., Amiridis, V., Baars, H., von Bismarck, J., Borne, M., Chen, S., Flamant, C., Marenco, F., Knipperz, P., Koopman, R., Lemmerz, C. L., Marinou, E., Močnik, G., Parrinello, T., Piña, A., Reitebuch, O., Skofronick-Jackson, G., Zawislak, J., and Zenk, C.: The Joint Aeolus Tropical Atlantic Campaign 2021/2022 Overview– Atmospheric Science and Satellite Validation in the Tropics, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-7249, https://doi.org/10.5194/egusphere-egu23-7249, 2023.
A continuation of the National Aeronautics and Space Administration’s (NASA) truncated Convective Processes Experiment – Aerosols and Winds (CPEX-AW) field program flown out of St. Croix, USVI, in the summer of 2021, CPEX – Cabo Verde (CPEX-CV) deployed NASA’s DC-8 from Sal Island, Cabo Verde in September 2022, equipped with a unique and comprehensive suite of active and passive remote sensing and in-situ capabilities that, in combination with the availability of similar spaceborne observations, allowed for the measurements of tropospheric aerosols, winds, temperature, water vapor, and clouds and precipitation. The tropical northern East Atlantic Ocean is a data sparse region that, in boreal summer, offers a unique location to study convective lifecycles and processes in a variety of thermodynamic, dynamic, and aerosol environments, such as within persistent (e.g., Intertropical Convergence Zone, ITCZ) and periodic (e.g., African easterly waves and tropical cyclones) large-scale forcing, local terrain effects (e.g., land-ocean transition off western Africa), and aerosol-cloud interactions (e.g., Saharan air layer). In addition to observing the interaction between large-scale environmental forcing and convective systems, the payload is uniquely capable of observing the smaller-scale processes within the near-environment of convection, including those within the marine boundary layer (e.g., cold pools), the inflow/outflow of the storm, and dust-cloud interactions, that affect convective initiation and lifecycle, as well as other poorly resolved/understood properties of these systems.
CPEX-AW and -CV were a part of a joint observing effort with the European Space Agency (ESA) and their partner laboratories and universities called the Joint Aeolus Tropical Atlantic Campaign (JATAC) out of Cabo Verde to validate ESA’s Aeolus satellite. As part of the CPEX-CV – JATAC collaboration in September 2022, the NASA DC-8 carried out coincident underpasses of the Aeolus satellite on four of the thirteen CPEX-CV research flights, performed four overpasses of the ASKOS ground site at Mindelo, and two coordinated flights with the Slovenian WT-10 in situ aircraft that also encompassed a coincident flight under Aeolus and over the Mindelo ground site. Here, we summarize the CPEX-CV science objectives, mission architecture, scientific targets observed on flights flown during the September 2022 campaign, and highlights of the data collected planned to be released to the community in early April 2023 with a focus on collaborative efforts between CPEX-CV and JATAC.
How to cite: Nowottnick, E., Zawislak, J., Nehrir, A., McCarty, W., Piña, A., Reid, J., Chen, S.-H., Rowe, A., Sakaeda, N., Chen, S., Zipser, E., Pu, Z., Robinson, C., Ferrare, R., Hristova-Veleva, S., Ziemba, L., Thornhill, L., Bedka, K., Kavaya, M., and Tanelli, S. and the CPEX-CV/JATAC Team: Overview of NASA’s Convective Processes Experiment – Cabo Verde (CPEX-CV) in the East Atlantic in September 2022 and Collaboration with the Joint Aeolus Tropical Atlantic Campaign (JATAC), EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-8956, https://doi.org/10.5194/egusphere-egu23-8956, 2023.
During June 2022, the Cyprus Institute (CyI) took part in the ASKOS experiment in Mindelo, Cape Verde, with several of Unmanned Aerial Vehicles (UAVs), fitted with a number of in-situ aerosol instruments able to profile the Saharan Air Layer between the surface and an altitude of 5,300 m. In addition to ASKOS objectives, transnational access project Diurnal vAriation of the vertically resolved siZe distribution in the Saharan Air Layer (DAZSAL) was also carried out at the same time. The campaign aimed at validating the Aeolus L2A product in the presence of dust and marine aerosols, estimating the influence on Aeolus products of non-spherical particles, evaluating the impact of particle orientation, and study the diurnal cycle of the dust size-distribution at high altitude. In this presentation we will present and discuss the scientific objectives, the context, the Unmanned Aerial Systems (UASs) that we developed in-house, and the instruments used, together with their limitations, calibration methods, uncertainties, challenges and difficulties encountered. We will also discuss the logistical and planning challenges that such a campaign entails.
Operations took place from the Cesaria Evora International Airport. The instruments deployed on-board the UAVs permitted to evaluate the height-resolved particle size-distribution between 0.1 and 40 µm and detect cases of particle orientation, to complement the observations with ground-based remote sensing set out by NOA and TROPOS. Moreover, 24 high-altitude dust samples were collected on impactors, for further analysis by Scanning Electron Microscopy. In total, 25 scientific flights were performed on 12 flying days (almost half of which at night). Five flights were conducted during Aeolus overpasses. Weather has been a determining factor for both the ground-based remote sensing operations and the UAS operation, and airport traffic has been another constraint that needed to be accounted for, in the UAS operation.
How to cite: Marenco, F., Kezoudi, M., Papetta, A., Keleshis, C., Ryder, C., Ratcliffe, N., Kandler, K., Girdwood, J., Stopford, C., Wienhold, F., Gao, R.-S., Marinou, E., Amiridis, V., Baars, H., Mocnik, G., and Sciare, J.: Unmanned Aerial Vehicles for the Joint Aeolus Tropical Atlantic Campaign, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-17089, https://doi.org/10.5194/egusphere-egu23-17089, 2023.
We present results from a cross-Atlantic validation of the Aeolus L2B wind product using radiosondes launched in the framework of the Joint Aeolus Tropical Atlantic Campaign (JATAC). Of the total of 20 profiles corresponding to Aeolus overflights, 11 were launched in August-September 2021 from western Puerto Rico and northern St Croix, coordinated by the University of Oklahoma and Utah respectively, and 9 in September 2021 from the semi-arid Cape Verdean island of Sal, coordinated by the Karlsruhe Institute of Technology (KIT).
During this period, Aeolus sampled a complex atmospheric environment with a variety of cloud types associated with the Intertropical Convergence Zone (ITCZ) and the West African Monsoon (WAM), as well as dust aerosol particles emitted from Saharan dust outbreaks. The results show that Aeolus Rayleigh-clear and Mie-cloudy wind products do not significantly depend on the collocation distance and time difference between Aeolus and radiosonde measurement. Nevertheless, the presence of clouds and dust can affect the quality of the Rayleigh-clear measurements by reducing the signal intensity of the backscattered light and with that the signal-to-noise ratio. Outliers with large absolute errors and low error estimates, accounting for less than 5% of the data, affect measurements at all altitudes and under all atmospheric conditions, and their cause remains unknown. Finally, we show the existence of an ascending/descending bias in the Rayleigh-clear channel, visible with respect to both radiosondes and European Centre for Medium-Range Weather Forecasts (ECMWF) model equivalents. The results of this study contribute to a better characterization of Aeolus' wind product in different atmospheric conditions and provide valuable information for further improvement of the wind retrieval algorithm.
How to cite: Borne, M., Knippertz, P., Weissmann, M., Witschas, B., Flamant, C., Rios-Berrios, R., and Veals, P.: Validation of Aeolus wind products over the tropical Atlantic using radiosondes, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-3222, https://doi.org/10.5194/egusphere-egu23-3222, 2023.
Abstract. The Joint Aeolus Tropical Atlantic Campaign (JATAC) for the Calibration and Validation (Cal/Val) of the ESA’s Aeolus mission was held on summer and September 2021 and 2022 at the remote tropical islands of Cabo Verde. The JATAC campaign comprises airborne and ground-based instrumentation delivering reference measurements of wind profiles and aerosol/cloud optical properties for the validation of the Aeolus products, as well as supporting related research activities. The ground-based component of JATAC, ASKOS (https://askos.space.noa.gr/) was stationed at the Ocean Science Center in Mindelo (OSCM), São Vicente Island, where measurements from active and passive remote sensing sensors have been deployed for the validation of the Aeolus Level 2 aerosol and wind products.
The eVe lidar, which is the ESA’s ground reference lidar system, was deployed in ASKOS for the validation of the Aeolus Level 2A aerosol products. eVe lidar is a scanning system that can perform combined linear/circular polarization and Raman measurements that operates at 355 nm and retrieves the particle backscatter coefficient, the particle extinction coefficient, the lidar ratio, and the linear and circular depolarization ratios. The lidar is implemented in a dual-laser/dual-telescope configuration that allows eVe to simultaneously reproduce the operation of the ALADIN lidar onboard Aeolus, i.e. circularly polarized emission, as well as the operation of a traditional lidar system, i.e. with linearly polarized emission. Targeted measurements of eVe lidar for the Aeolus validation were performed every Friday evening during the nearest Aeolus overpass from Mindelo resulting to a dataset of fourteen collocations for the intensive ASKOS operation periods in 2021 and 2022. In this study, we present the results from the comparison of the particle backscatter and extinction coefficients, and the lidar ratio between eVe and Aeolus profiles.
Acknowledgements:
This research was supported by the European Space Agency project ASKOS (Grant agreement 4000131861/20/NL/IA) and the PANGEA4CalVal project (Grant Agreement 101079201) funded by European Union’s Horizon Widera 2021 Access program.
How to cite: Paschou, P., Siomos, N., Marinou, E., Gkikas, A., Moussa Idrissa, S., Tetteh Quaye, D., Dêgbé Fiogbe Attannon, D., Meleti, C., von Bismarck, J., Fehr, T., and Amiridis, V.: Validation of the Aeolus L2A products with the eVe lidar during ASKOS/JATAC campaign, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-14445, https://doi.org/10.5194/egusphere-egu23-14445, 2023.
Aeolus, ESA’s space mission, provides vertical profiles of the HLOS wind component in the troposphere and the lower stratosphere. In addition, ALADIN thanks to its HSLR configuration retrieves and provides profiles of extinction/backscatter coefficients of aerosols and clouds (known as spin-off or L2A products), at the ultraviolet region of the spectrum (355nm). However, ALADIN’s design enables the detection only of the returned co-polar component of the transmitted light. This inherent limitation hampers the ability of ALADIN to provide realistic optical products (i.e., underestimated backscatter coefficient profiles) when non-spherical particles (e.g., dust, volcanic ash, cirrus ice crystals) are probed, a deficiency for the case of Earth Observation of highly depolarizing targets with negative impacts on applications of Data Assimilation (DA) and Numerical Weather Prediction (NWP).
The ESA L2A+ (Enhancing Aeolus L2A for depolarizing targets and impact on aerosol research and NWP) project kicked off in November 2022, with an overarching objective to develop a refined Aeolus L2A aerosol product (L2A+) and test its application for enhancing aerosol research. The generation of the refined L2A+ Aeolus aerosol optical product will be based, among others, on an integrated approach of novel algorithms (i.e., AEL-FM/AEL-PRO), model outputs (i.e., CAMS), advanced EO-based products (i.e., MSG, MODIS-MIDAS), existing climatologies (ESA-LIVAS), and AOD retrievals from Aeolus itself. The product will be thoroughly compared with L2A and validated against quality-assured measurements from the ESA-ASKOS/JATAC experiment in Cape Verde.
With respect to the overarching objectives on aerosol research, L2A+ aims to (1) examine the impact of L2A and L2A+ on aerosol assimilation and dust transport models, (2) assess the impact of Aeolus on NWP, (3) highlight the benefit of the Aeolus joint aerosol and wind assimilation for simulating dust deposition fields, (4) assess the climatological value of L2A+ for aerosol databases such as the ESA-LIVAS long-term climate dataset, and (5) assess the impact of the novel L2A+ product on aerosol assimilation, towards improved dust transport modelling and for further enhancing NWP.
The ESA-L2A+ project focuses on the broader the Western Sahara and the Tropical Atlantic Ocean, while due to the extensive wealth of available observational data collected in the framework of the European Space Agency (ESA) ASKOS Tropical Campaign in Cape Verde, which are needed for a complete and descriptive assessment analysis of the project outputs and the evaluation of the enhanced L2A+ product, the developments and experiments will be performed for September 2021.
Preliminary results from the project will be presented.
The L2A+ team acknowledges support by ESA in the framework of the "Enhancing Aeolus L2A for depolarizing targets and impact on aerosol research and NWP project (4000139424/22/I-NS).
How to cite: Georgiou, T., Proestakis, E., Gkikas, A., Rizos, K., Drakaki, E., Kampouri, A., Tsikerdekis, A., Baars, H., Floutsi, A. A., Benedetti, A., and Amiridis, V.: Enhancing Aeolus L2A for depolarizing targets and impact on aerosol research and NWP , EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-17110, https://doi.org/10.5194/egusphere-egu23-17110, 2023.
In the frame of the Joint Aeolus Tropical Atlantic Campaigns, an airborne field campaign took place in Sal island of Cape-Verde from the 8th to 21st of September 2021, as part of the French CADDIWA mission. During this campaign, the SAFIRE F20 research aircraft equipped with in situ and remote sensing instruments performed nine 3 to 4 hour long flights sampling tropical environment underneath AEOLUS satellite tracks and performing exploration flights within the convective cloud systems of tropical disturbances. In this study, an overview of the available aerosol and cloud in situ dataset is given first, presenting the instrumental and methodological approaches relevant to the collection of data from a set of four instruments: the UHSAS (aerosol size range : 40 – 1000 nm, Cai et al. 2008), the SPP-300 (aerosol 0.3 – 20 µm, Baumgardner 1992) and the CDP-2 (droplets 2-50 µm, Lance et al. 2010) scattering probes, and the 2D-S imager (10-1280 µm, Lawson et al. 2006). Then a detailed microphysical analysis is conducted on two case studies: a tropical perturbation referred to as Pierre-Henri in this study (unnamed/numbered by NOAA National Hurricane Center (NHC)), sampled during F20 flight #7/8, and the Tropical Storm Rose (# AL172021 according to NOAA NHC) sampled during flights #12/13. The analysis includes a discussion on the main microphysical properties such as Particle Size Distribution (PSD), Ice Water Content (IWC) retrieved at different locations in the cloud convective systems, complemented by 95GHz reflectivity and Doppler vertical velocity measured by the airborne cloud radar RASTA (Delanoe et al. 2013). The data supporting this study is illustrated in the figure below: the vertical velocity (derived from 3 Doppler non colinear measurements of the radar) and PSD time series are given on top of two samples ice crystal images taken by the 2DS imager at different location in the TS Rose. A newly developed image classification algorithm (Jaffeux et al. 2022) is applied to the 2D-S data to derive statistics on the ice particles morphological properties, yielding to a discussion on the microphysical ice growth processes occurring in these systems.
How to cite: Coutris, P., Febvre, G., Jaffeux, L., Bazantay, C., Aubry, C., Caudoux, C., Delanoë, J., Schwarzenboeck, A., and Flamant, C.: Overview and first analysis of the in situ microphysical measurement dataset collected during the CADDIWA mission, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-13084, https://doi.org/10.5194/egusphere-egu23-13084, 2023.
The Joint Aeolus Tropical Atlantic Campaigns (JATAC) 2021 and 2022 deployed on the US Virgin Islands and Cabo Verde, respectively, with science objectives related to the life cycle of convective systems, the long-range transport of dust and its impact on air quality, and the satellite calibration/validation of current and the preparation of future ESA and NASA missions (Aeolus, EarthCARE, AOS, WIVERN). The NASA components of JATAC, Convective Processes Experiment-Aerosols and Winds (CPEX-AW) and CPEX–Cabo Verde (CPEX-CV), included a focus on the complex multi-scale processes and interactions that lead to convective development and its upscale growth: Understanding the environmental conditions supporting the development of tropical cyclones (TCs) remains a research and operational challenge, owing in part to limited observations of the lifecycle of convective activity that eventually become TCs. In the Atlantic basin, early stages of TC development favor the region off the west coast of Africa as African Easterly Waves move offshore and provide, at times, favorable conditions for TC development. CPEX-CV provided airborne measurements in this region, with a total of 13 research flights throughout September 2022. The payload included a triple-frequency precipitation radar, Doppler wind lidar, and dropsondes, among other remote sensing and in situ instrumentation, offering a rare 4-D look at tropical oceanic convective systems and their environment.
To support the campaign goals, we developed the JPL CPEX-AW/CV portal (https://cpex-aw.jpl.nasa.gov), which integrates model forecasts with multi-parameter satellite and airborne observations from a variety of instruments. The portal provides an interactive system for multi-scale visualization and on-line analysis, allowing for the interrogation of a large number of variables for flight planning and execution and for post-campaign analysis, including the large-scale context of the detailed airborne observations. In this presentation, the portal will be used to provide an initial investigation into the evolution of a tropical wave observed during CPEX-CV. The 16 September 2022 flight targeted a growing convective system associated with a broad circulation, the wave structure itself, an Aeolus validation underflight, and dust over Mindelo in coordination with other JATAC measurements. While the wave was not forecasted to immediately develop into a TC downstream, the convection sampled on the western edge of the wave was intense with lightning, although did not grow upscale into a large organized mesoscale convective system during or immediately after the flight. A focus of this initial portal-based analysis is on gradients in environmental moisture, evolution of environmental wind shear in the vicinity of the precipitation, and the presence (or absence) of large-scale convergence as we suspect some combination of these factors limited the initial development of this convective system into a tropical cyclone. Potential later large-scale ties to the development of Hurricane Ian in the Caribbean will also be explored with the portal as it provided a useful tool for this purpose.
How to cite: Hristova-Veleva, S., Rowe, A., Zipser, E., Zawislak, J., Li, P. P., Knosp, B., Vu, Q., and Eriksen, J.: Investigating the evolution of a tropical wave observed during JATAC/CPEX-CV using the campaign data portal, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-10983, https://doi.org/10.5194/egusphere-egu23-10983, 2023.
During the CADDIWA (Cloud-Atmospheric Dynamics-Dust Interaction in West Africa) airborne campaign that took place in September 2021, three tropical disturbances initiated from African Easterly Waves were sampled. Two of them reached the Tropical Storm state and were named Rose and Peter by the National Hurricane Center. The last one, later named Pierre-Henri, failed to develop. After a validation of reanalysis data for september 2021 against the data collected during the campaign, a comparative study of the three events will be conducted using ERA5, satellite and campaign data, with a focus on energy budgets. Several processes that may be catalysts or inhibiters for tropical cyclogenesis (AEW-Monsoon -, AEW-AEW -, dust-dynamics interaction ...) will especially be discussed.
How to cite: Jonville, T., Flamant, C., Lavaysse, C., Delanoë, J., Richard, P., Bounissou, S., Cazenave, Q., Colomb, H., Caudoux, C., Peyrillé, P., and Cornillault, E.: Development of Tropical Cyclones from African Easterly Waves : comparative study of three African Easterly Wave events during the CADDIWA campaign, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-1087, https://doi.org/10.5194/egusphere-egu23-1087, 2023.
At the end of the monsoonal season in West Africa, tropical cyclones (TCs) start to develop in the Northern Tropical Atlantic off shore Senegal, south of Cape Verde. TCs generally develop from low pressure disturbances travelling westward from West Africa embedded in the African easterly waves (AEWs), characterised by organised convection and high specific humidity. Some of these TCs eventually evolve into tropical storms and hurricanes. However, whereas there is overall agreement concerning the main necessary conditions, involving sea surface temperature (SST) and vertical wind shear, for a TC to evolve into a tropical storm or a hurricane, the elements concurring to the formation of TCs from easterly depressions are still unclear. Indeed, the environment where the transition occurs is characterised by complex interactions involving atmospheric dynamics and aerosol-cloud-radiation interactions not fully understood yet.
The purpose of this study is to contribute to enlighten the mechanisms leading an easterly African depression to evolve (or not) into a TC in the Northern Tropical Atlantic, by characterising the atmospheric environment off shore Senegal and south of Cape Verde, where TCs start to develop. To this aim, a weather regime (WR) classification of the atmospheric variability is first performed on a climatological time scale in a region including West Africa and Northern Tropical Atlantic. The WR classification is then used to characterise the relevant atmospheric variables involved in the TC development. In particular, the role of major outbreaks of mineral aerosols from the adjacent Sahara Desert is investigated. Data from ERA5 and CAMS reanalysis products are analysed for the period 1991-2020.
How to cite: Gaetani, M., Flamant, C., Jonville, T., Chaboureau, J.-P., Lavaysse, C., Cuesta, J., Menut, L., Castillo, N., and Formenti, F.: Weather regime characterisation of the atmospheric environment leading to the development of tropical cyclones in the Northern Tropical Atlantic, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-4556, https://doi.org/10.5194/egusphere-egu23-4556, 2023.
Wind profiles in the lower troposphere influence the processes driving cloud formation and dissipation. For example, dendritic cumulus and linear sheets formations are governed by different factors including wind direction and velocity. Trade winds and local dynamic processes influence the formation of cumulus and stratocumulus.
Using multiple case studies where the ALADIN lidar observes the different cloud patterns mentioned above, we will see how AEOLUS retrieves winds and clouds and what are the links between them. This study will be backed by visible MODIS observations and Calipso-GOCCP data to confirm the presence of clouds and their types. The focus will be around the JATAC area (Cape Verde, June to September 2021 and 2022), especially in the boundary layer, where our knowledge about the interactions between the wind and clouds are yet to be improved.
How to cite: Titus, Z. and Chepfer, H.: Studying interactions between low clouds and wind profiles using ALADIN/AEOLUS data, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-9467, https://doi.org/10.5194/egusphere-egu23-9467, 2023.
Tropical storms, especially when they develop into hurricanes, are among the most destructive natural disasters. They are the subject of numerous studies, in particular to better understand their dynamics on meteorological scales in order to better predict them and reduce their impacts. We have been able to understand the role of African easterly waves in the formation of tropical storms in the Cape Verde region. However, the role of desert dust originating from the Sahara remains poorly understood due to their multiple and antagonistic effects in stabilizing the atmosphere by heating and reinvigorating convection through cloud icing as well as the lack of observation and limited simulation capabilities.
The CADDIWA (Clouds-Atmospheric Dynamics-Dust Interactions in West Africa) project aims to better understand the effects of desert dust on the atmospheric circulation off Senegal. The CADDIWA airborne campaign, took place from September 5 to 23, 2021 operating the SAFIRE Falcon 20 in the tropical environment of the Cape Verde Islands. During the campaign, the tropical storm Rose was observed on September 18 and 19, 2021. The goal of this PhD project is to exploit current very high resolution modeling capabilities combined with new observations to understand the dynamical and microphysical processes responsible for the development of Tropical Storm Rose. The first results of a large-eddy simulation of Tropical Storm Rose will be presented as well as its evaluation by comparison with available airborne and satellite observations.
How to cite: Feger, G., Dauhut, T., and Chaboureau, J.-P.: The role of desert dust in the development of the Tropical Storm Rose, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-938, https://doi.org/10.5194/egusphere-egu23-938, 2023.
Abstract. Dust orientation is an ongoing investigation in recent years (Ulanowski et al., 2007). Its potential proof will be a paradigm shift for dust remote sensing, invalidating the currently used simplifications of randomly-oriented particles. Vertically-resolved measurements of dust orientation can be acquired with the new polarization lidar “WALL-E”, designed to target the off-diagonal elements of the backscatter matrix which are non-zero only when the particles are oriented (Tsekeri et al., 2021). Herein, we present first measurements of oriented dust particles acquired during the ESA Aeolus Cal/Val Campaign “ASKOS” at Cabo Verde (June and September 2022).
Acknowledgments: This research was supported by D-TECT (Grant Agreement 725698) funded by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program and PANGEA4CalVal (Grant Agreement 101079201) funded by European Union’s Horizon Widera 2021 Access program.
References:
Tsekeri, A., et al.: Polarization lidar for detecting dust orientation: system design and calibration, Atmos. Meas. Tech., 14, 7453–7474, 2021.
Ulanowski, Z., et al.: Alignment of atmospheric mineral dust due to electric field, Atmos. Chem. Phys., 7, 6161–6173, 2007.
How to cite: Tsekeri, A., Amiridis, V., Metallinos, S., Paschou, P., Siomos, N., Tsikoudi, I., Kouklaki, D., and Marinou, E.: Dust orientation measurements, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-14575, https://doi.org/10.5194/egusphere-egu23-14575, 2023.
From 19 September to 13 December 2021, a volcanic eruption took place at Las Palmas, Canary Islands. Thereby, fine ash and volatiles, like SO2, were emitted and transported over hundreds to thousand kilometers away from the island [1]. At the same time, continuous lidar observations with the multiwavelength-Raman-polarization lidar PollyXT were performed at the Ocean Science Center Mindelo (16.878°N, 24.995°W), Cabo Verde, in the frame of the JATAC-campaign 2021/2022. During autumn, typical aerosol conditions over Mindelo, as detected by the lidar, are a clean marine boundary layer up to approx. 1 km and a Saharan dust layer (up to 6 km) above. In the boundary layer, an extinction coefficient of less than 200 Mm-1 and a lidar ratio smaller than 40 sr is typically observed while a lidar ratio between 40 and 60 sr and a depolarization ratio between 20 and 30 % is typically found for the Saharan dust properties. Instead, during the time of the volcanic eruption, a strongly polluted planetary boundary layer (PBL) was observed beginning 23 of September, whereby the extinction coefficient and the lidar ratio increased up to 800 Mm-1 and 60 to 80 sr, respectively. On specific days, the aerosol optical depth, determined by an AERONET sun photometer, was as high as 1.0 (at 500 nm). Due to the small depolarization ratio around 0 % in the PBL and Hysplit trajectories indicating air masses coming from Canary Islands, the observed pollution over Mindelo can be attributed to sulfates emitted by the volcanic eruption at Las Palmas. No indications for volcanic ash over Mindelo were found, neither in the PBL nor in the lofted layer (mainly Saharan dust). This is furthermore supported by Hysplit trajectories, which show that air masses in higher altitudes come from the African continent and not from the Canary Islands. The potential of Aeolus to capture the volcanic plume on its way to Cabo Verde will also be assessed using the aerosol spin-off products (L2A) of the most recently available baseline.
References
[1] Carracedo, J. C., Troll, V. R., Day, J. M., Geiger, H., Aulinas, M., Soler, V., ... & Albert, H. (2022). The 2021 eruption of the Cumbre Vieja Volcanic Ridge on La Palma, Canary Islands. Geology Today, 38(3), 94-107.
How to cite: Gebauer, H., Baars, H., Floutsi, A. A., Ansmann, A., Ohneiser, K., and Zenk, C.: Lidar measurements of volcanic aerosol over Mindelo during the volcanic eruption at Las Palmas in autumn 2021, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-3398, https://doi.org/10.5194/egusphere-egu23-3398, 2023.
Mineral dust aerosols are composed from a complex assemblage of various minerals depending on the region they come from. Considering that minerals have their distinct physicochemical properties, differences on mineral dust aerosols climatic impact will arise as a consequence of distinct mineral content.
Chemical transport models typically assume that mineral dust aerosols have uniform composition, despite the known regional variations in the mineral components. This study adds mineralogical information to the mineral dust emission scheme used in the chemical transport model, COSMO-MUSCAT.
Here we show some steps of the inclusion of mineralogy to the emission scheme. Results of the simulated mineral dust aerosols are shown with their respective mineralogy from sources in Africa for an example case from the JATAC campaign in September 2021. The results of the simulated mineral dust aerosol are compared with lidar and in-situ data measured at Mindelo, Cape Verde. Furthermore, the comparison with the lidar retrieved vertical profiles at Mindelo, highlights a possible link between the mineral dust aerosol optical properties and the distinct minerals found within them.
How to cite: Gómez Maqueo Anaya, S., Althausen, D., Schepanski, K., Faust, M., Heinold, B., Tegen, I., Baars, H., Engelmann, R., Skupin, A., Radenz, M., Ansmann, A., Hesse, B., Wandinger, U., Mocnik, G., Silva, E., Rodrigues, E., Silva, P., and Zenk, C.: Dust aerosols’ mineralogy in the chemical transport model COSMO-MUSCAT during JATAC and comparison with lidar and in-situ data, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-15338, https://doi.org/10.5194/egusphere-egu23-15338, 2023.
As support to the operational field campaign of the CADDIWA field experiment, the coupled regional model WRF-CHIMERE in forecast mode during the summer 2021. The simulation domain covers West Africa and the East Atlantic and allows the modeling of dust emissions and their transport to the Atlantic. On this route, we find Cape Verde which was used as a base for measurements during the CADDIWA campaign. The forecast consists of meteorological variables and mineral dust concentrations on a horizontal grid with a resolution of 30 km and from the surface to 200 hPa. Each day, the simulation starts the day before (D-1) and up to 4 days ahead (D+4). For each day, we thus have 6 different calculations, with logically a better precision the closer we get to the analysis (D-1). This presentation will show a quantification of the variability of the forecast of mineral dust according to the modelled lead. This quantification will also be done according to the interactions between clouds, aerosols and radiation.
How to cite: Menut, L.: Meteorology and mineral dust forecast variability during the CADDIWA campaign, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-1162, https://doi.org/10.5194/egusphere-egu23-1162, 2023.
