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1.
The Joint Aeolus Tropical Atlantic Campaign 2021/2022 overview : atmospheric science and satellite validation in the tropics
Thorsten Fehr, Griša Močnik, 2023, published scientific conference contribution abstract

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.
Keywords: Aeolus satellite, airborne measurements, mineral dust, cal/val, calibration, validation
Published in RUNG: 21.12.2023; Views: 1534; Downloads: 5
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2.
Aeolus calibration, validation and science campaigns
Thorsten Fehr, Vassilis Amiridis, Sebastian Bley, Philippe Cocquerez, Christian Lemmerz, Griša Močnik, Gail Skofronick-Jackson, Anne Grete Straume, 2020, published scientific conference contribution abstract

Abstract: Since 2007, a series of ESA supported airborne campaigns have been essential to the development of the Aeolus Doppler Wind Lidar satellite mission, which was successfully launched on 22 September 2018 and is providing a novel wind and aerosol profile data. A core element of the Aeolus Cal/Val activities is DLR’s A2D wind lidar on-board the DLR Falcon aircraft, an airborne demonstrator for the Aeolus ALADIN satellite instrument flown in combination with the 2-µm Doppler Wind Lidar reference system. Following the pre-launch WindVal-I and –II campaigns in 2015 and 2016, a number of calibration and validation campaigns have been successfully implemented: WindVal-III providing early Cal/Val results in November 2018 only three months after the Aeolus launch, AVATAR-E in May 2019 focussing on the Cal/Val over Central Europe, and AVATAR-I in September 2019 providing Cal/Val information in the North Atlantic and Arctic flying from Iceland. The airborne validation is also being supported through balloon flights in the tropical UTLS and lower stratosphere in the frame of the CNES Stratéole-2 stratospheric balloon activities. In the frame of the ESA supported pre-Stratéole-2 campaign, eight stratospheric balloons have been launched from the Seychelles in November/December 2019 providing unique upper level wind data for the Aeolus validation. The largest impact of the Aeolus observations is expected in the Tropics, and in particular over the Tropical oceans, where only a limited number of wind profile information is provided by ground based observations. Aeolus provides key direct measurements which are of importance to correctly constrain the wind fields in models. In addition, Aeolus observations have the potential to further enhance our current knowledge on aerosols and clouds by globally providing optical properties products that include atmospheric backscatter and extinction coefficient profiles, lidar ratio profiles and scene classification. In the tropics, a particularly interesting case is the outflow of Saharan dust and its impact on micro-physics in tropical cloud systems. The region off the coast of West Africa allows the study of the Saharan Aerosol layer, African Easterly Waves and Jets, Tropical Easterly Jet, as well as the deep convection in ITCZ. Together with international partners, ESA is currently implementing a Tropical campaign in July 2020 with its base in Cape Verde that comprises both airborne and ground-based activities addressing the tropical winds and aerosol validation, as well as science objectives. The airborne component includes the DLR Falcon-20 carrying the A2D and 2-µm Doppler Wind lidars, the NASA P-3 Orion with the DAWN and HALO lidar systems, the APR Ku-, Ka- and W-band Doppler radar and drop sondes, and a Slovenian small aircraft providing in-situ information from aethalometers, nephelometers and optical particle counters. The ground-based component led by the National Observatory of Athens is a collaboration of European teams providing aerosol and cloud measurements with a range of lidar, radar and radiometer systems, as well as a drone providing in-situ aerosol observations. In addition, the participation airborne capabilities by NOAA and LATMOS/Meteo France are currently being investigated. This paper will provide a summary of the Aeolus campaign focussing on the planned tropical campaign.
Keywords: Aeolus satellite, ALADIN, aerosol, validation
Published in RUNG: 23.08.2022; Views: 2079; Downloads: 69
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