Yiu, YYS and Maycock, AC orcid.org/0000-0002-6614-1127 (2020) The linearity of the El Niño teleconnection to the Amundsen Sea region. Quarterly Journal of the Royal Meteorological Society, 146 (728). pp. 1169-1183. ISSN 0035-9009
Abstract
El Niño Southern Oscillation (ENSO) drives interannual variability in West Antarctic climate through altering atmospheric circulation in the Amundsen Sea region (ASR). The El Niño–ASR teleconnection is known to be strongest in austral winter and spring, but its variation with El Niño amplitude is underexplored. This study uses experiments from the HadGEM3‐A climate model to investigate the El Niño–ASR teleconnection for a range of imposed SST perturbations spanning weak (0.75 K) to strong (3 K) amplitudes. In austral winter, the El Niño–ASR teleconnection behaves linearly for El Niño amplitudes up to 2.25 K, but is found to weaken for stronger forcing (3 K). The anomalous Rossby wave source in the subtropical South Pacific increases monotonically with El Niño amplitude. However, a Rossby wave reflection surface originally located in the western South Pacific sector extends progressively eastward with increasing El Niño amplitude, reducing wave propagation into the ASR. The wave reflection surface is associated with curvature in the upper tropospheric zonal winds which intensifies as the subtropical jet strengthens under El Niño forcing. In contrast, the El Niño–ASR teleconnection in austral summer, which more closely resembles the Southern Annular Mode, is found to increase linearly for El Niño amplitudes up to 3 K. The results explicitly demonstrate that a linear approximation of the El Niño teleconnection to the ASR is reasonable based on the range of El Niño amplitudes observed in recent history.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 The Authors. Quarterly Journal of the Royal Meteorological Society published by John Wiley & Sons Ltd on behalf of the Royal Meteorological Society. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. |
Keywords: | Amundsen Sea low; El Niño; ENSO; linearity; Rossby waves; teleconnection; West Antarctic climate |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Inst for Climate & Atmos Science (ICAS) (Leeds) |
Funding Information: | Funder Grant number NERC (Natural Environment Research Council) NE/M018199/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 23 Dec 2019 09:46 |
Last Modified: | 18 Dec 2020 12:02 |
Status: | Published |
Publisher: | Wiley |
Identification Number: | 10.1002/qj.3731 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:154883 |