Characteristics and rarity of the strong 1940s westerly wind event over the Amundsen Sea, West Antarctica
<p>Glaciers in the Amundsen Sea Embayment of West Antarctica are rapidly retreating and contributing to sea level rise. Ice loss is occurring primarily via exposure to warm ocean water, which varies in response to local wind variability. There is evidence that retreat was initiated in the mid-...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2023-10-01
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| Series: | The Cryosphere |
| Online Access: | https://tc.copernicus.org/articles/17/4399/2023/tc-17-4399-2023.pdf |
| _version_ | 1797656128620855296 |
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| author | G. K. O'Connor P. R. Holland E. J. Steig E. J. Steig P. Dutrieux G. J. Hakim |
| author_facet | G. K. O'Connor P. R. Holland E. J. Steig E. J. Steig P. Dutrieux G. J. Hakim |
| author_sort | G. K. O'Connor |
| collection | DOAJ |
| description | <p>Glaciers in the Amundsen Sea Embayment of West Antarctica are rapidly retreating and contributing to sea level rise. Ice loss is occurring primarily via exposure to warm ocean water, which varies in response to local wind variability. There is evidence that retreat was initiated in the mid-20th century, but the perturbation that may have triggered retreat remains unknown. A leading hypothesis is that large pressure and wind anomalies in the 1940s drove exceptionally strong oceanic ice-shelf melting. However, the characteristics, drivers, and rarity of the atmospheric event remain poorly constrained. We investigate the 1940s atmospheric event using paleoclimate reconstructions and climate model simulations. The reconstructions show that large westerly wind anomalies occurred from <span class="inline-formula">∼1938</span>–1942, a combined response to the very large El Niño event from 1940–1942 and other variability beginning years earlier. Climate model simulations provide evidence that events of similar magnitude and duration may occur tens to hundreds of times per 10 kyr of internal climate variability (<span class="inline-formula">∼0.2</span> to 2.5 occurrences per century). Our results suggest that the 1940s westerly event is unlikely to have been exceptional enough to be the sole explanation for the initiation of Amundsen Sea glacier retreat. Additional factors are likely needed to explain the onset of retreat in West Antarctica, such as naturally arising variability in ocean conditions prior to the 1940s or anthropogenically driven trends since the 1940s.</p> |
| first_indexed | 2024-03-11T17:24:53Z |
| format | Article |
| id | doaj.art-8352b2080d414b8ebef619e854170fd0 |
| institution | Directory Open Access Journal |
| issn | 1994-0416 1994-0424 |
| language | English |
| last_indexed | 2024-03-11T17:24:53Z |
| publishDate | 2023-10-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | The Cryosphere |
| spelling | doaj.art-8352b2080d414b8ebef619e854170fd02023-10-19T05:16:11ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242023-10-01174399442010.5194/tc-17-4399-2023Characteristics and rarity of the strong 1940s westerly wind event over the Amundsen Sea, West AntarcticaG. K. O'Connor0P. R. Holland1E. J. Steig2E. J. Steig3P. Dutrieux4G. J. Hakim5Department of Earth and Space Sciences, University of Washington, Seattle, WA, USABritish Antarctic Survey, Cambridge, UKDepartment of Earth and Space Sciences, University of Washington, Seattle, WA, USADepartment of Atmospheric Sciences, University of Washington, Seattle, WA, USABritish Antarctic Survey, Cambridge, UKDepartment of Atmospheric Sciences, University of Washington, Seattle, WA, USA<p>Glaciers in the Amundsen Sea Embayment of West Antarctica are rapidly retreating and contributing to sea level rise. Ice loss is occurring primarily via exposure to warm ocean water, which varies in response to local wind variability. There is evidence that retreat was initiated in the mid-20th century, but the perturbation that may have triggered retreat remains unknown. A leading hypothesis is that large pressure and wind anomalies in the 1940s drove exceptionally strong oceanic ice-shelf melting. However, the characteristics, drivers, and rarity of the atmospheric event remain poorly constrained. We investigate the 1940s atmospheric event using paleoclimate reconstructions and climate model simulations. The reconstructions show that large westerly wind anomalies occurred from <span class="inline-formula">∼1938</span>–1942, a combined response to the very large El Niño event from 1940–1942 and other variability beginning years earlier. Climate model simulations provide evidence that events of similar magnitude and duration may occur tens to hundreds of times per 10 kyr of internal climate variability (<span class="inline-formula">∼0.2</span> to 2.5 occurrences per century). Our results suggest that the 1940s westerly event is unlikely to have been exceptional enough to be the sole explanation for the initiation of Amundsen Sea glacier retreat. Additional factors are likely needed to explain the onset of retreat in West Antarctica, such as naturally arising variability in ocean conditions prior to the 1940s or anthropogenically driven trends since the 1940s.</p>https://tc.copernicus.org/articles/17/4399/2023/tc-17-4399-2023.pdf |
| spellingShingle | G. K. O'Connor P. R. Holland E. J. Steig E. J. Steig P. Dutrieux G. J. Hakim Characteristics and rarity of the strong 1940s westerly wind event over the Amundsen Sea, West Antarctica The Cryosphere |
| title | Characteristics and rarity of the strong 1940s westerly wind event over the Amundsen Sea, West Antarctica |
| title_full | Characteristics and rarity of the strong 1940s westerly wind event over the Amundsen Sea, West Antarctica |
| title_fullStr | Characteristics and rarity of the strong 1940s westerly wind event over the Amundsen Sea, West Antarctica |
| title_full_unstemmed | Characteristics and rarity of the strong 1940s westerly wind event over the Amundsen Sea, West Antarctica |
| title_short | Characteristics and rarity of the strong 1940s westerly wind event over the Amundsen Sea, West Antarctica |
| title_sort | characteristics and rarity of the strong 1940s westerly wind event over the amundsen sea west antarctica |
| url | https://tc.copernicus.org/articles/17/4399/2023/tc-17-4399-2023.pdf |
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