Which Extratropical Cyclones Contribute Most to the Transport of Moisture in the Southern Hemisphere?
Predicted changes in Southern Hemisphere (SH) precipitation and Antarctic ice mass correspond to variations in the meridional moisture flux (MMF). Thirty-five years of ERA-Interim reanalysis data are combined with an extratropical cyclone (ETC) identification and tracking algorithm to investigate fa...
Published in: | Journal of Geophysical Research: Atmospheres |
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American Geophysical Union
2019
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Online Access: | http://hdl.handle.net/10138/302090 |
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ftunivhelsihelda:oai:helda.helsinki.fi:10138/302090 2024-01-07T09:38:41+01:00 Which Extratropical Cyclones Contribute Most to the Transport of Moisture in the Southern Hemisphere? Sinclair, V. A. Dacre, H. F. INAR Physics Institute for Atmospheric and Earth System Research (INAR) 2019-05-24T09:33:02Z 21 application/pdf http://hdl.handle.net/10138/302090 eng eng American Geophysical Union 10.1029/2018JD028766 Sinclair , V A & Dacre , H F 2019 , ' Which Extratropical Cyclones Contribute Most to the Transport of Moisture in the Southern Hemisphere? ' , Journal of Geophysical Research : Atmospheres , vol. 124 , no. 5 , pp. 2525-2545 . https://doi.org/10.1029/2018JD028766 RIS: urn:BDD37AED423576775DD1C0FE9A5B3385 ORCID: /0000-0002-2125-4726/work/57797303 1066fe5a-c97d-4045-a651-8157f3880b08 http://hdl.handle.net/10138/302090 000462139800009 unspecified openAccess info:eu-repo/semantics/openAccess 1171 Geosciences extra-tropical cyclones meridional moisture transport Antarctica precipitation Southern Hemisphere OCEAN SIGNALS TRENDS ORIGIN ERA-40 TRACKING SNOW ACCUMULATION extratropical cyclones DRONNING MAUD LAND CLIMATE Article acceptedVersion 2019 ftunivhelsihelda 2023-12-14T00:06:43Z Predicted changes in Southern Hemisphere (SH) precipitation and Antarctic ice mass correspond to variations in the meridional moisture flux (MMF). Thirty-five years of ERA-Interim reanalysis data are combined with an extratropical cyclone (ETC) identification and tracking algorithm to investigate factors controlling SH MMF variability in the midlatitudes and near Antarctica. ETC characteristics which exert the strongest control on ETC MMF are determined thus identifying which ETCs contribute most to SH moisture transport. ETC poleward propagation speed exerts the strongest control on the ETC MMF across the Antarctic coastline. In SH winter, ETCs with the largest poleward propagation speeds transport 2.5 times more moisture than an average ETC. In the midlatitudes, ETC genesis latitude and poleward propagation speed have a similar influence on ETC MMF. Surprisingly, ETC maximum vorticity has little control on ETC MMF. Cyclone compositing is used to determine the reasons for these statistical relationships. ETCs generally exhibit a dipole of poleward and equatorward MMF downstream and upstream of the cyclone center, respectively. However, ETCs with the largest poleward propagation speeds resemble open frontal waves with strong poleward moisture transport downstream of the cyclone center only and thus result in the largest MMF. These results suggest that inhomogeneous trends and predicted changes in precipitation over Antarctica may be due to changes in cyclone track orientation, associated with changes to the large-scale background flow, in addition to changes in cyclone number or intensity. Peer reviewed Article in Journal/Newspaper Antarc* Antarctic Antarctica Dronning Maud Land HELDA – University of Helsinki Open Repository Antarctic Dronning Maud Land The Antarctic Journal of Geophysical Research: Atmospheres 124 5 2525 2545 |
institution |
Open Polar |
collection |
HELDA – University of Helsinki Open Repository |
op_collection_id |
ftunivhelsihelda |
language |
English |
topic |
1171 Geosciences extra-tropical cyclones meridional moisture transport Antarctica precipitation Southern Hemisphere OCEAN SIGNALS TRENDS ORIGIN ERA-40 TRACKING SNOW ACCUMULATION extratropical cyclones DRONNING MAUD LAND CLIMATE |
spellingShingle |
1171 Geosciences extra-tropical cyclones meridional moisture transport Antarctica precipitation Southern Hemisphere OCEAN SIGNALS TRENDS ORIGIN ERA-40 TRACKING SNOW ACCUMULATION extratropical cyclones DRONNING MAUD LAND CLIMATE Sinclair, V. A. Dacre, H. F. Which Extratropical Cyclones Contribute Most to the Transport of Moisture in the Southern Hemisphere? |
topic_facet |
1171 Geosciences extra-tropical cyclones meridional moisture transport Antarctica precipitation Southern Hemisphere OCEAN SIGNALS TRENDS ORIGIN ERA-40 TRACKING SNOW ACCUMULATION extratropical cyclones DRONNING MAUD LAND CLIMATE |
description |
Predicted changes in Southern Hemisphere (SH) precipitation and Antarctic ice mass correspond to variations in the meridional moisture flux (MMF). Thirty-five years of ERA-Interim reanalysis data are combined with an extratropical cyclone (ETC) identification and tracking algorithm to investigate factors controlling SH MMF variability in the midlatitudes and near Antarctica. ETC characteristics which exert the strongest control on ETC MMF are determined thus identifying which ETCs contribute most to SH moisture transport. ETC poleward propagation speed exerts the strongest control on the ETC MMF across the Antarctic coastline. In SH winter, ETCs with the largest poleward propagation speeds transport 2.5 times more moisture than an average ETC. In the midlatitudes, ETC genesis latitude and poleward propagation speed have a similar influence on ETC MMF. Surprisingly, ETC maximum vorticity has little control on ETC MMF. Cyclone compositing is used to determine the reasons for these statistical relationships. ETCs generally exhibit a dipole of poleward and equatorward MMF downstream and upstream of the cyclone center, respectively. However, ETCs with the largest poleward propagation speeds resemble open frontal waves with strong poleward moisture transport downstream of the cyclone center only and thus result in the largest MMF. These results suggest that inhomogeneous trends and predicted changes in precipitation over Antarctica may be due to changes in cyclone track orientation, associated with changes to the large-scale background flow, in addition to changes in cyclone number or intensity. Peer reviewed |
author2 |
INAR Physics Institute for Atmospheric and Earth System Research (INAR) |
format |
Article in Journal/Newspaper |
author |
Sinclair, V. A. Dacre, H. F. |
author_facet |
Sinclair, V. A. Dacre, H. F. |
author_sort |
Sinclair, V. A. |
title |
Which Extratropical Cyclones Contribute Most to the Transport of Moisture in the Southern Hemisphere? |
title_short |
Which Extratropical Cyclones Contribute Most to the Transport of Moisture in the Southern Hemisphere? |
title_full |
Which Extratropical Cyclones Contribute Most to the Transport of Moisture in the Southern Hemisphere? |
title_fullStr |
Which Extratropical Cyclones Contribute Most to the Transport of Moisture in the Southern Hemisphere? |
title_full_unstemmed |
Which Extratropical Cyclones Contribute Most to the Transport of Moisture in the Southern Hemisphere? |
title_sort |
which extratropical cyclones contribute most to the transport of moisture in the southern hemisphere? |
publisher |
American Geophysical Union |
publishDate |
2019 |
url |
http://hdl.handle.net/10138/302090 |
geographic |
Antarctic Dronning Maud Land The Antarctic |
geographic_facet |
Antarctic Dronning Maud Land The Antarctic |
genre |
Antarc* Antarctic Antarctica Dronning Maud Land |
genre_facet |
Antarc* Antarctic Antarctica Dronning Maud Land |
op_relation |
10.1029/2018JD028766 Sinclair , V A & Dacre , H F 2019 , ' Which Extratropical Cyclones Contribute Most to the Transport of Moisture in the Southern Hemisphere? ' , Journal of Geophysical Research : Atmospheres , vol. 124 , no. 5 , pp. 2525-2545 . https://doi.org/10.1029/2018JD028766 RIS: urn:BDD37AED423576775DD1C0FE9A5B3385 ORCID: /0000-0002-2125-4726/work/57797303 1066fe5a-c97d-4045-a651-8157f3880b08 http://hdl.handle.net/10138/302090 000462139800009 |
op_rights |
unspecified openAccess info:eu-repo/semantics/openAccess |
container_title |
Journal of Geophysical Research: Atmospheres |
container_volume |
124 |
container_issue |
5 |
container_start_page |
2525 |
op_container_end_page |
2545 |
_version_ |
1787424970622631936 |