Opposing shifts of the Hadley cell edge and eddy-driven jet latitude in the Last Glacial Maximum
A coherent poleward displacement of the Hadley cell (HC) edge and eddy-driven jet latitude has been well documented in the Southern Hemisphere (SH) under the present and future climate changes. However, a recent study showed that during the Last Glacial Maximum (LGM) winter, an equatorward shift of...
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ftgfzpotsdam:oai:gfzpublic.gfz-potsdam.de:item_5019356 2023-07-16T03:57:03+02:00 Opposing shifts of the Hadley cell edge and eddy-driven jet latitude in the Last Glacial Maximum Kim, S. Son, S. 2023 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5019356 eng eng info:eu-repo/semantics/altIdentifier/doi/10.57757/IUGG23-2547 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5019356 XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) info:eu-repo/semantics/conferenceObject 2023 ftgfzpotsdam https://doi.org/10.57757/IUGG23-2547 2023-06-25T23:39:53Z A coherent poleward displacement of the Hadley cell (HC) edge and eddy-driven jet latitude has been well documented in the Southern Hemisphere (SH) under the present and future climate changes. However, a recent study showed that during the Last Glacial Maximum (LGM) winter, an equatorward shift of the HC edge but a poleward shift of the jet latitude are found in the SH. These opposing circulation changes are investigated in this study by conducting the parameter sweep experiments using a dynamical core GCM. By systematically varying the amplitude of tropical upper-tropospheric and polar surface cooling, mimicking the LGM-like climate state, an opposing shift of circulation is reproduced when polar cooling is much stronger than tropical cooling. This is due to the higher sensitivity of the jet-latitude change compared to the HC-edge change in response to polar cooling. Eddy cospectra analysis reveals that the poleward jet shift is dominated by fast waves as the baroclinic zone expands poleward with increasing polar surface cooling. Instead, the HC-edge change is largely attributed to the activity of slow waves and the axisymmetric circulation change. They lead to the HC edge being weakly influenced by extratropical baroclinicity, resulting in an equatorward shift of the HC edge under a global cooling–like condition. Similar circulation changes but with an opposite sign are also found in global warming–like experiments. It suggests that a poleward HC shift together with an equatorward jet shift can occur even in a future climate if Arctic amplification is accelerated relative to tropical warming. Conference Object Arctic Global warming GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) Arctic |
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Open Polar |
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GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) |
op_collection_id |
ftgfzpotsdam |
language |
English |
description |
A coherent poleward displacement of the Hadley cell (HC) edge and eddy-driven jet latitude has been well documented in the Southern Hemisphere (SH) under the present and future climate changes. However, a recent study showed that during the Last Glacial Maximum (LGM) winter, an equatorward shift of the HC edge but a poleward shift of the jet latitude are found in the SH. These opposing circulation changes are investigated in this study by conducting the parameter sweep experiments using a dynamical core GCM. By systematically varying the amplitude of tropical upper-tropospheric and polar surface cooling, mimicking the LGM-like climate state, an opposing shift of circulation is reproduced when polar cooling is much stronger than tropical cooling. This is due to the higher sensitivity of the jet-latitude change compared to the HC-edge change in response to polar cooling. Eddy cospectra analysis reveals that the poleward jet shift is dominated by fast waves as the baroclinic zone expands poleward with increasing polar surface cooling. Instead, the HC-edge change is largely attributed to the activity of slow waves and the axisymmetric circulation change. They lead to the HC edge being weakly influenced by extratropical baroclinicity, resulting in an equatorward shift of the HC edge under a global cooling–like condition. Similar circulation changes but with an opposite sign are also found in global warming–like experiments. It suggests that a poleward HC shift together with an equatorward jet shift can occur even in a future climate if Arctic amplification is accelerated relative to tropical warming. |
format |
Conference Object |
author |
Kim, S. Son, S. |
spellingShingle |
Kim, S. Son, S. Opposing shifts of the Hadley cell edge and eddy-driven jet latitude in the Last Glacial Maximum |
author_facet |
Kim, S. Son, S. |
author_sort |
Kim, S. |
title |
Opposing shifts of the Hadley cell edge and eddy-driven jet latitude in the Last Glacial Maximum |
title_short |
Opposing shifts of the Hadley cell edge and eddy-driven jet latitude in the Last Glacial Maximum |
title_full |
Opposing shifts of the Hadley cell edge and eddy-driven jet latitude in the Last Glacial Maximum |
title_fullStr |
Opposing shifts of the Hadley cell edge and eddy-driven jet latitude in the Last Glacial Maximum |
title_full_unstemmed |
Opposing shifts of the Hadley cell edge and eddy-driven jet latitude in the Last Glacial Maximum |
title_sort |
opposing shifts of the hadley cell edge and eddy-driven jet latitude in the last glacial maximum |
publishDate |
2023 |
url |
https://gfzpublic.gfz-potsdam.de/pubman/item/item_5019356 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Global warming |
genre_facet |
Arctic Global warming |
op_source |
XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.57757/IUGG23-2547 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5019356 |
op_doi |
https://doi.org/10.57757/IUGG23-2547 |
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1771543570780520448 |