Synoptic and planetary-scale dynamics modulate antarctic atmospheric river precipitation intensity

• Published in: Communications Earth & Environment
• Main Authors: Baiman, Rebecca, Winters, Andrew, C, Pohl, Benjamin, Favier, Vincent, Wille, Jonathan, D, Clem, Kyle, R
• Other Authors: Department of Atmospheric and Oceanic Sciences Boulder (ATOC), University of Colorado Boulder, Centre de Recherches de Climatologie UMR Biogéosciences (CRC), Biogéosciences UMR 6282 (BGS), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS)-Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Victoria University of Wellington, ANR-20-CE01-0013,ARCA,Climatologie des rivières atmosphériques en Antarctique(2020)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2024
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Antarctic; Merra; Antarc*; Antarctica
• Online Access: https://hal.science/hal-04505424; https://hal.science/hal-04505424/document; https://hal.science/hal-04505424/file/BWPFWC2024.pdf; https://doi.org/10.1038/s43247-024-01307-9

International audience Although rare, atmospheric rivers substantially influence the interannual variability of Antarctic surface mass balance. Here we use MERRA-2 reanalysis to identify characteristics unique to atmospheric river environments by comparing (1) Analog (environments that feature high-low pressure couplets, similar to Atmospheric River environments, but no Atmospheric River), (2) Atmospheric River, and (3) Top Atmospheric River (highest precipitation) timesteps during 1980–2019 around Antarctica. We find significant differences between Atmospheric River and Analog environments including more intense and poleward-shifted mid-tropospheric geopotential height couplets as well as larger atmospheric moisture anomalies. We find similar significant enhancement in synoptic-scale dynamic drivers of Top Atmospheric Rivers compared to all Atmospheric River environments, but no significant difference in local integrated water vapor anomalies. Instead, our results highlight the importance of large-scale dynamic drivers during Top Atmospheric River timesteps, including amplified Rossby waves excited by tropical convection.