Southern Ocean heat storage, reemergence, and winter sea ice decline induced by summertime winds
Ó 2021 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy The observational record shows a substantial 40-yr upward trend in summertime westerly winds over the Southern Ocean, as characterized by the so...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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American Meteorological Society
2021
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| Online Access: | https://hdl.handle.net/1721.1/133818 |
| _version_ | 1811089244004810752 |
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| author | Doddridge, Edward W Marshall, John Song, Hajoon Campin, Jean-Michel Kelley, Maxwell |
| author_facet | Doddridge, Edward W Marshall, John Song, Hajoon Campin, Jean-Michel Kelley, Maxwell |
| author_sort | Doddridge, Edward W |
| collection | MIT |
| description | Ó 2021 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy The observational record shows a substantial 40-yr upward trend in summertime westerly winds over the Southern Ocean, as characterized by the southern annular mode (SAM) index. Enhanced summertime westerly winds have been linked to cold summertime sea surface temperature (SST) anomalies. Previous studies have suggested that Ekman transport or upwelling is responsible for this seasonal cooling. Here, another process is presented in which enhanced vertical mixing, driven by summertime wind anomalies, moves heat downward, cooling the sea surface and simultaneously warming the subsurface waters. The anomalously cold SSTs draw heat from the atmosphere into the ocean, leading to increased depth-integrated ocean heat content. The subsurface heat is returned to the surface mixed layer during the autumn and winter as the mixed layer deepens, leading to anomalously warm SSTs and potentially reducing sea ice cover. Observational analyses and numerical experiments support our proposed mechanism, showing that enhanced vertical mixing produces subsurface warming and cools the surface mixed layer. Nevertheless, the dominant driver of surface cooling remains uncertain; the relative importance of advective and mixing contributions to the surface cooling is model dependent. Modeling results suggest that sea ice volume is more sensitive to summertime winds than sea ice extent, implying that enhanced summertime westerly winds may lead to thinner sea ice in the following winter, if not lesser ice extent. Thus, strong summertime winds could precondition the sea ice cover for a rapid retreat in the following melt season. |
| first_indexed | 2024-09-23T14:16:07Z |
| format | Article |
| id | mit-1721.1/133818 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T14:16:07Z |
| publishDate | 2021 |
| publisher | American Meteorological Society |
| record_format | dspace |
| spelling | mit-1721.1/1338182021-10-28T03:39:37Z Southern Ocean heat storage, reemergence, and winter sea ice decline induced by summertime winds Doddridge, Edward W Marshall, John Song, Hajoon Campin, Jean-Michel Kelley, Maxwell Ó 2021 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy The observational record shows a substantial 40-yr upward trend in summertime westerly winds over the Southern Ocean, as characterized by the southern annular mode (SAM) index. Enhanced summertime westerly winds have been linked to cold summertime sea surface temperature (SST) anomalies. Previous studies have suggested that Ekman transport or upwelling is responsible for this seasonal cooling. Here, another process is presented in which enhanced vertical mixing, driven by summertime wind anomalies, moves heat downward, cooling the sea surface and simultaneously warming the subsurface waters. The anomalously cold SSTs draw heat from the atmosphere into the ocean, leading to increased depth-integrated ocean heat content. The subsurface heat is returned to the surface mixed layer during the autumn and winter as the mixed layer deepens, leading to anomalously warm SSTs and potentially reducing sea ice cover. Observational analyses and numerical experiments support our proposed mechanism, showing that enhanced vertical mixing produces subsurface warming and cools the surface mixed layer. Nevertheless, the dominant driver of surface cooling remains uncertain; the relative importance of advective and mixing contributions to the surface cooling is model dependent. Modeling results suggest that sea ice volume is more sensitive to summertime winds than sea ice extent, implying that enhanced summertime westerly winds may lead to thinner sea ice in the following winter, if not lesser ice extent. Thus, strong summertime winds could precondition the sea ice cover for a rapid retreat in the following melt season. 2021-10-27T19:56:49Z 2021-10-27T19:56:49Z 2021 2021-09-17T13:48:37Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/133818 en 10.1175/JCLI-D-20-0322.1 Journal of Climate Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Meteorological Society American Meteorological Society (AMS) |
| spellingShingle | Doddridge, Edward W Marshall, John Song, Hajoon Campin, Jean-Michel Kelley, Maxwell Southern Ocean heat storage, reemergence, and winter sea ice decline induced by summertime winds |
| title | Southern Ocean heat storage, reemergence, and winter sea ice decline induced by summertime winds |
| title_full | Southern Ocean heat storage, reemergence, and winter sea ice decline induced by summertime winds |
| title_fullStr | Southern Ocean heat storage, reemergence, and winter sea ice decline induced by summertime winds |
| title_full_unstemmed | Southern Ocean heat storage, reemergence, and winter sea ice decline induced by summertime winds |
| title_short | Southern Ocean heat storage, reemergence, and winter sea ice decline induced by summertime winds |
| title_sort | southern ocean heat storage reemergence and winter sea ice decline induced by summertime winds |
| url | https://hdl.handle.net/1721.1/133818 |
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