The Joint Aeolus Tropical Atlantic Campaign 2021/2022 Overview– Atmospheric Science and Satellite Validation in the Tropics

Abstract

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.