The Aeolus satellite: a new look at gravity waves and tropical dynamics

• Main Authors: Ratynski, Mathieu, Khaykin, Sergey, Hauchecorne, Alain, Alexander, Joan, Mariaccia, Alexis, Keckhut, Philippe, Tremoulu, Samuel, Chane Ming, Fabrice, Mangin, Antoine
• Other Authors: Rosenstiel School of Marine and Atmospheric Science (RSMAS), University of Miami Coral Gables, STRATO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), NorthWest Research Associates Boulder (NWRA), Laboratoire de l'Atmosphère et des Cyclones (LACy), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Météo-France, Analytic and Computational Research, Inc. - Earth Sciences (ACRI-ST)
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2024
• Subjects: [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]; Antarc*; Antarctica; Greenland
• Online Access: https://insu.hal.science/insu-04682764

International audience The European Space Agency's Aeolus satellite, equipped with the Atmospheric LAser Doppler INstrument (ALADIN), provides comprehensive global wind profiling, offering valuable insights into convection-induced gravity waves (GWs) in the upper troposphere and lower stratosphere (UTLS). This study analyzes Aeolus-derived wind data alongside ECMWF ERA5 reanalysis, revealing a migrating hotspot of enhanced GW activity. This activity transitions from the Indian Ocean during the Boreal Summer to the Maritime Continent in Boreal Winter, correlating strongly with convective activity as evidenced by variability in outgoing longwave radiation. The results underscore the importance of Aeolus in improving the representation of convective-induced GWs in ERA5, particularly in the under-sampled Indian Ocean region, thus enhancing our understanding of GW phenomena in the UTLS. While the benefits of Aeolus global wind profiling are straightforward, important limitations exist, particularly when studying extratropical UTLS dynamics. We identify and characterize these limitations in our study, focusing on the Range Bin Setting (RBS) of Aeolus. This RBS adjusts dynamically based on seasonal and geographical variations, affecting our ability to measure and interpret gravity wave dynamics accurately. We also examine oscillatory perturbations (OPs) identified in Aeolus data, particularly between 12 and 19 km altitudes, displaying a unique oscillatory signature. These OPs emerge prominently above high-albedo regions such as Greenland and Antarctica. The nature of these oscillations remains unexplained although the dark current anomalies on the instruments (hot pixels) may amplify these oscillations without explaining their inherent characteristics. The absence of these phenomena in GNSS Radio Occultation data suggests that the observed perturbations in Aeolus data are not related to gravity waves but are likely linked to the satellite's specific observational characteristics. These variations introduce ...