Characteristics of summer airflow over the Antarctic Peninsula in response to recent strengthening of westerly circumpolar winds
Summer near-surface temperatures over the northeast coast of the Antarctic Peninsula have increased by more than 2°C over the past 40 years, a temperature increase 3 times greater than that on the northwest coast. Recent analysis has shown a strong correlation between this striking warming trend and...
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Language: | English |
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2008
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Online Access: | https://www.vliz.be/imisdocs/publications/355631.pdf |
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ftvliz:oai:oma.vliz.be:331275 2023-05-15T13:53:33+02:00 Characteristics of summer airflow over the Antarctic Peninsula in response to recent strengthening of westerly circumpolar winds Orr, A. Marshall, G.J. Hunt, J.C.R. Sommeria, J. Wang, C.-G. van Lipzig, N.P.M. Cresswell, D. King, J.C. 2008 application/pdf https://www.vliz.be/imisdocs/publications/355631.pdf en eng info:eu-repo/semantics/altIdentifier/wos/000255362400015 info:eu-repo/semantics/altIdentifier/doi/doi.org/10.1175/2007jas2498.1 https://www.vliz.be/imisdocs/publications/355631.pdf info:eu-repo/semantics/openAccess %3Ci%3EJ.+Atmos.+Sci.+65%284%29%3C%2Fi%3E%3A+1396-1413.+%3Ca+href%3D%22https%3A%2F%2Fdx.doi.org%2F10.1175%2F2007jas2498.1%22+target%3D%22_blank%22%3Ehttps%3A%2F%2Fdx.doi.org%2F10.1175%2F2007jas2498.1%3C%2Fa%3E info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2008 ftvliz https://doi.org/10.1175/2007jas2498.1 2022-05-01T11:49:58Z Summer near-surface temperatures over the northeast coast of the Antarctic Peninsula have increased by more than 2°C over the past 40 years, a temperature increase 3 times greater than that on the northwest coast. Recent analysis has shown a strong correlation between this striking warming trend and significant change in the summer Southern Hemisphere annular mode (SAM), which has resulted in greatly increased summer westerlies across the northern peninsula. It has been proposed that the strengthening westerlies have resulted in increased vertical deflection of relatively warm maritime air over the northern peninsula, contributing significantly to the observed warming and the recent collapse of northern sections of the Larsen Ice Shelf. In this study, laboratory and numerical modeling of airflow incident to the peninsula are employed to further understand this mechanism. It is shown that the effect of the strengthening westerlies has led to a distinct transition from a “blocked” regime to a “flow-over” regime, that is, confirmation of the proposed warming mechanism. The blocked regime is dominated by flow stagnation upstream (i.e., little vertical deflection) and consequent lateral deflection of flow along the western side of the peninsula. The flow-over regime is dominated by vertical deflection of mid/upper-level air over the peninsula, with strong downslope winds following closely to the leeward slope transporting this air (which warms adiabatically as it descends) to the near-surface of the northeast peninsula. The strong rotation typical of high latitudes considerably increases the flow over the peninsula, particularly strengthening it over the southern side (verified by aircraft measurements), suggesting that the warming trend is not solely confined to the northeast. Globally, flow regime transitions such as this may be responsible for other local climate variations. Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Ice Shelf Larsen Ice Shelf Flanders Marine Institute (VLIZ): Open Marine Archive (OMA) Antarctic The Antarctic Antarctic Peninsula Larsen Ice Shelf ENVELOPE(-62.500,-62.500,-67.500,-67.500) Journal of the Atmospheric Sciences 65 4 1396 1413 |
institution |
Open Polar |
collection |
Flanders Marine Institute (VLIZ): Open Marine Archive (OMA) |
op_collection_id |
ftvliz |
language |
English |
description |
Summer near-surface temperatures over the northeast coast of the Antarctic Peninsula have increased by more than 2°C over the past 40 years, a temperature increase 3 times greater than that on the northwest coast. Recent analysis has shown a strong correlation between this striking warming trend and significant change in the summer Southern Hemisphere annular mode (SAM), which has resulted in greatly increased summer westerlies across the northern peninsula. It has been proposed that the strengthening westerlies have resulted in increased vertical deflection of relatively warm maritime air over the northern peninsula, contributing significantly to the observed warming and the recent collapse of northern sections of the Larsen Ice Shelf. In this study, laboratory and numerical modeling of airflow incident to the peninsula are employed to further understand this mechanism. It is shown that the effect of the strengthening westerlies has led to a distinct transition from a “blocked” regime to a “flow-over” regime, that is, confirmation of the proposed warming mechanism. The blocked regime is dominated by flow stagnation upstream (i.e., little vertical deflection) and consequent lateral deflection of flow along the western side of the peninsula. The flow-over regime is dominated by vertical deflection of mid/upper-level air over the peninsula, with strong downslope winds following closely to the leeward slope transporting this air (which warms adiabatically as it descends) to the near-surface of the northeast peninsula. The strong rotation typical of high latitudes considerably increases the flow over the peninsula, particularly strengthening it over the southern side (verified by aircraft measurements), suggesting that the warming trend is not solely confined to the northeast. Globally, flow regime transitions such as this may be responsible for other local climate variations. |
format |
Article in Journal/Newspaper |
author |
Orr, A. Marshall, G.J. Hunt, J.C.R. Sommeria, J. Wang, C.-G. van Lipzig, N.P.M. Cresswell, D. King, J.C. |
spellingShingle |
Orr, A. Marshall, G.J. Hunt, J.C.R. Sommeria, J. Wang, C.-G. van Lipzig, N.P.M. Cresswell, D. King, J.C. Characteristics of summer airflow over the Antarctic Peninsula in response to recent strengthening of westerly circumpolar winds |
author_facet |
Orr, A. Marshall, G.J. Hunt, J.C.R. Sommeria, J. Wang, C.-G. van Lipzig, N.P.M. Cresswell, D. King, J.C. |
author_sort |
Orr, A. |
title |
Characteristics of summer airflow over the Antarctic Peninsula in response to recent strengthening of westerly circumpolar winds |
title_short |
Characteristics of summer airflow over the Antarctic Peninsula in response to recent strengthening of westerly circumpolar winds |
title_full |
Characteristics of summer airflow over the Antarctic Peninsula in response to recent strengthening of westerly circumpolar winds |
title_fullStr |
Characteristics of summer airflow over the Antarctic Peninsula in response to recent strengthening of westerly circumpolar winds |
title_full_unstemmed |
Characteristics of summer airflow over the Antarctic Peninsula in response to recent strengthening of westerly circumpolar winds |
title_sort |
characteristics of summer airflow over the antarctic peninsula in response to recent strengthening of westerly circumpolar winds |
publishDate |
2008 |
url |
https://www.vliz.be/imisdocs/publications/355631.pdf |
long_lat |
ENVELOPE(-62.500,-62.500,-67.500,-67.500) |
geographic |
Antarctic The Antarctic Antarctic Peninsula Larsen Ice Shelf |
geographic_facet |
Antarctic The Antarctic Antarctic Peninsula Larsen Ice Shelf |
genre |
Antarc* Antarctic Antarctic Peninsula Ice Shelf Larsen Ice Shelf |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Ice Shelf Larsen Ice Shelf |
op_source |
%3Ci%3EJ.+Atmos.+Sci.+65%284%29%3C%2Fi%3E%3A+1396-1413.+%3Ca+href%3D%22https%3A%2F%2Fdx.doi.org%2F10.1175%2F2007jas2498.1%22+target%3D%22_blank%22%3Ehttps%3A%2F%2Fdx.doi.org%2F10.1175%2F2007jas2498.1%3C%2Fa%3E |
op_relation |
info:eu-repo/semantics/altIdentifier/wos/000255362400015 info:eu-repo/semantics/altIdentifier/doi/doi.org/10.1175/2007jas2498.1 https://www.vliz.be/imisdocs/publications/355631.pdf |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1175/2007jas2498.1 |
container_title |
Journal of the Atmospheric Sciences |
container_volume |
65 |
container_issue |
4 |
container_start_page |
1396 |
op_container_end_page |
1413 |
_version_ |
1766258744609472512 |