Multi‐Decadal Variability of Amundsen Sea Low Controlled by Natural Tropical and Anthropogenic Drivers

Abstract A crucial factor influencing the mass balance of the West Antarctic Ice Sheet is the Amundsen Sea Low (ASL), a climatological low‐pressure region situated off the West Antarctic coast. However, albeit the deepening of the ASL since the 1950s has been attributed to anthropogenic forcing, the...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Quentin Dalaiden, Nerilie J. Abram, Hugues Goosse, Paul R. Holland, Gemma K. O’Connor, Dániel Topál
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2024
Subjects:
Geophysics. Cosmic physics
QC801-809
Amundsen Sea
Antarctic
Pacific
West Antarctic Ice Sheet
Antarc*
Ice Sheet
Online Access:https://doi.org/10.1029/2024GL109137
https://doaj.org/article/9b72a47c839741eea31d74e0529bf85f
Description
Summary:Abstract A crucial factor influencing the mass balance of the West Antarctic Ice Sheet is the Amundsen Sea Low (ASL), a climatological low‐pressure region situated off the West Antarctic coast. However, albeit the deepening of the ASL since the 1950s has been attributed to anthropogenic forcing, the multi‐decadal variability of the ASL remains poorly understood, because of a lack of long observations. Here, we apply a newly developed data assimilation method to reconstruct the ASL over 1870–2000. We study the forced and internal variability of the ASL using our new reconstruction in concert with existing large ensembles of climate model simulations. Our findings robustly demonstrate that an atmospheric teleconnection originating from the tropical Indo‐Pacific is the main driver of ASL variability at the multi‐decadal time scale, with resemblance to the Interdecadal Pacific Oscillation. Since the mid‐20th century, anthropogenic forcing has emerged as a dominant contributor to the strengthening of the ASL.

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