The Joint Aeolus Tropical Atlantic Campaign - First Results for Aeolus Calibration/Validation and Science in the Tropics

International audience; ESA’s Aeolus satellite observations are expected to have the biggest impact for the improvement of numerical weather prediction in the Tropics. An especially important case relating to the evolution, dynamics, and 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 Atlantic Ocean off the coast of West Africa and the eastern Caribbean uniquely allows the study of the Saharan Aerosol layer, African Easterly Waves and Jet, Tropical Easterly Jet, as well as the deep convection in the Intertropical Convergence Zone and their relation to the formation of convective systems, and the long-range transport of dust and its impact on air quality. The Joint Aeolus Tropical Atlantic Campaign (JATAC) deployed on Cabo Verde and the US Virgin Islands is addressing the validation and preparation of the ESA missions Aeolus, EarthCARE and WIVERN, as well as supporting the related science objectives raised above. The JATAC campaign started in July 2021 with the deployment of ground-based instruments at the Ocean Science Center Mindelo (OSCM, Cabo Verde), including the EVE lidar, the PollyXT lidar, a W-band Doppler cloud radar and a sunphotometer. By mid-August, the CPEX-AW campaign started their operations from the US Virgin Islands with NASA’s DC-8 flying laboratory in the Western Tropical Atlantic and Caribbean with the Doppler Aerosol Wind Lidar (DAWN), Airborne Precipitation and Cloud Radar (APR-3), the Water Vapor DIAL and HSRL (HALO), a microwave sounder (HAMSR) and dropsondes. In September, a European aircraft fleet was deployed to Sal (Cabo Verde) with the DLR Falcon-20 carrying the Aeolus 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 among others. The Aerovizija Advantic WT-10 light aircraft with filter-photometers and nephelometers for in-situ aerosol characterisation was operating in close coordination with the ground-based observations from Mindelo. More than 35 flights of the four aircraft were performed. 17 Aeolus orbits were underflown, four of which completed by simultaneous observations of three aircraft, with a perfect collocation of Aeolus and the ground-based observation for two cases. Several flights by the NASA DC-8 and the Safire Falcon-20 have been dedicated to cloud microphysics and dust events. The EVE lidar has been operating on a regular basis, while the PollyXT and several other ground-based instruments were continuously operating during the campaign period. For further characterisation of the atmosphere, radiosondes were launched up to twice daily from Sal airport. Additionally, there were radiosonde launches from western Puerto Rico and northern St Croix, US Virgin Islands. The JATAC was supported by dedicated numerical weather and dust simulations supporting the forecasting efforts needed for successful planning of the flights and addressing open science questions. While the airborne activities were completed end September, the ground-based observations are continuing into 2022. The paper will present an overview and initial results of JATAC. In memory of our colleague and friend Gail.