Antarctic atmospheric river climatology and impacts

Due to the increased ability of the air to hold moisture with temperature, precipitation in Antarctica is expected to increase significantly over the next century. This process will undoubtedly lead to an increase in snow accumulation on the continent, thereby partially mitigating future sea level r...

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Bibliographic Details
Main Author: Wille, Jonathan
Other Authors: 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)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Université Grenoble Alpes 2020-., Vincent Favier, Francis Codron
Format: Doctoral or Postdoctoral Thesis
Language:English
Published: HAL CCSD 2021
Subjects:
Atmospheric rivers
Antarctica
Surface mass balance
Bilan de masse de surface
Antarctique
Rivières atmosphériques
[SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology
Antarc*
Antarctic
Antarctic Peninsula
Antarctique*
Dronning Maud Land
East Antarctica
Ice Shelf
Ice Shelves
Marie Byrd Land
Ross Ice Shelf
West Antarctica
Online Access:https://theses.hal.science/tel-03276308
https://theses.hal.science/tel-03276308/document
https://theses.hal.science/tel-03276308/file/WILLE_2021_archivage.pdf
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Summary:Due to the increased ability of the air to hold moisture with temperature, precipitation in Antarctica is expected to increase significantly over the next century. This process will undoubtedly lead to an increase in snow accumulation on the continent, thereby partially mitigating future sea level rise. However, recent observed trends in temperature and snow accumulation in Antarctica are insignificant and paradoxical. The role played by moisture intrusions in temperature and precipitation variability could partly explain this phenomenon. These events are known to transport warm air masses from the oceans to the Antarctic continent, but only individual and unrelated intrusion events have been described so far. In an earlier study of the Dronning Maud Land region, the description of atmospheric rivers (ARs) provided an innovative view to describe high intensity moisture intrusions. In this thesis, we develop an atmospheric river detection algorithm adapted to the polar regions, in order to create a climatology of these events at the Antarctic scale. Using the outputs of the regional climate model, MAR (Regional Atmospheric Model), we evaluate the impacts of atmospheric rivers on the melting in West Antarctic, ice-shelf stability on the Antarctic Peninsula ice shelves, and on snowfall across the Antarctic ice sheet.Atmospheric rivers are infrequent events with coastal areas of Antarctica experiencing AR conditions around only three days per year on average and this value is even lower in Antarctic interior. However, ARs control surface melting processes on West Antarctica and precipitation variability on East Antarctica. In the west, ARs entering the interior of the continent cause positive anomalies in downward longwave radiation via highly liquid-laden clouds and wind, resulting in a marked foehn effect along leeward slopes. Between 1979 and 2017, rivers were thus associated with about 40% of the summer melt on the Ross Ice Shelf (nearly 100% at higher altitudes on Marie Byrd Land) and 40-80% of the winter melt ...

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