The seasonal cycle of blocking and associated physical mechanisms in the Australian region and relationship with rainfall
The seasonal cycle of blocking in the Australian region is shown to be associated with major seasonal temperature changes over continental Antarctica (approximately 15-35C) and Australia (about 8-17C) and with minor changes over the surrounding oceans (below 5C). These changes are superimposed on a...
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ftunivtasecite:oai:ecite.utas.edu.au:119090 2023-05-15T13:49:03+02:00 The seasonal cycle of blocking and associated physical mechanisms in the Australian region and relationship with rainfall Pook, MJ Risbey, JS McIntosh, PC Ummenhofer, CC Marshall, AG Meyers, GA 2013 application/pdf https://doi.org/10.1175/MWR-D-13-00040.1 http://ecite.utas.edu.au/119090 en eng Amer Meteorological Soc http://ecite.utas.edu.au/119090/1/The Seasonal Cycle of Blocking.pdf http://dx.doi.org/10.1175/MWR-D-13-00040.1 Pook, MJ and Risbey, JS and McIntosh, PC and Ummenhofer, CC and Marshall, AG and Meyers, GA, The seasonal cycle of blocking and associated physical mechanisms in the Australian region and relationship with rainfall, Monthly Weather Review, 141, (12) pp. 4534-4553. ISSN 0027-0644 (2013) [Refereed Article] http://ecite.utas.edu.au/119090 Earth Sciences Atmospheric Sciences Meteorology Refereed Article PeerReviewed 2013 ftunivtasecite https://doi.org/10.1175/MWR-D-13-00040.1 2019-12-13T22:18:22Z The seasonal cycle of blocking in the Australian region is shown to be associated with major seasonal temperature changes over continental Antarctica (approximately 15-35C) and Australia (about 8-17C) and with minor changes over the surrounding oceans (below 5C). These changes are superimposed on a favorable background state for blocking in the region resulting from a conjunction of physical influences. These include the geographical configuration and topography of the Australian and Antarctic continents and the positive west to east gradient of sea surface temperature in the Indo-Australian sector of the Southern Ocean. Blocking is represented by a blocking index (BI) developed by the Australian Bureau of Meteorology. The BI has a marked seasonal cycle that reflects seasonal changes in the strength of the westerly winds in the midtroposphere at selected latitudes. Significant correlations between the BI at Australian longitudes and rainfall have been demonstrated in southern and central Australia for the austral autumn, winter, and spring. Patchy positive correlations are evident in the south during summer but significant negative correlations are apparent in the central tropical north. By decomposing the rainfall into its contributions from identifiable synoptic types during the April-October growing season, it is shown that the high correlation between blocking and rainfall in southern Australia is explained by the component of rainfall associated with cutoff lows. These systems form the cyclonic components of blocking dipoles. In contrast, there is no significant correlation between the BI and rainfall from Southern Ocean fronts. Article in Journal/Newspaper Antarc* Antarctic Antarctica Southern Ocean eCite UTAS (University of Tasmania) Antarctic Southern Ocean Austral Monthly Weather Review 141 12 4534 4553 |
institution |
Open Polar |
collection |
eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Earth Sciences Atmospheric Sciences Meteorology |
spellingShingle |
Earth Sciences Atmospheric Sciences Meteorology Pook, MJ Risbey, JS McIntosh, PC Ummenhofer, CC Marshall, AG Meyers, GA The seasonal cycle of blocking and associated physical mechanisms in the Australian region and relationship with rainfall |
topic_facet |
Earth Sciences Atmospheric Sciences Meteorology |
description |
The seasonal cycle of blocking in the Australian region is shown to be associated with major seasonal temperature changes over continental Antarctica (approximately 15-35C) and Australia (about 8-17C) and with minor changes over the surrounding oceans (below 5C). These changes are superimposed on a favorable background state for blocking in the region resulting from a conjunction of physical influences. These include the geographical configuration and topography of the Australian and Antarctic continents and the positive west to east gradient of sea surface temperature in the Indo-Australian sector of the Southern Ocean. Blocking is represented by a blocking index (BI) developed by the Australian Bureau of Meteorology. The BI has a marked seasonal cycle that reflects seasonal changes in the strength of the westerly winds in the midtroposphere at selected latitudes. Significant correlations between the BI at Australian longitudes and rainfall have been demonstrated in southern and central Australia for the austral autumn, winter, and spring. Patchy positive correlations are evident in the south during summer but significant negative correlations are apparent in the central tropical north. By decomposing the rainfall into its contributions from identifiable synoptic types during the April-October growing season, it is shown that the high correlation between blocking and rainfall in southern Australia is explained by the component of rainfall associated with cutoff lows. These systems form the cyclonic components of blocking dipoles. In contrast, there is no significant correlation between the BI and rainfall from Southern Ocean fronts. |
format |
Article in Journal/Newspaper |
author |
Pook, MJ Risbey, JS McIntosh, PC Ummenhofer, CC Marshall, AG Meyers, GA |
author_facet |
Pook, MJ Risbey, JS McIntosh, PC Ummenhofer, CC Marshall, AG Meyers, GA |
author_sort |
Pook, MJ |
title |
The seasonal cycle of blocking and associated physical mechanisms in the Australian region and relationship with rainfall |
title_short |
The seasonal cycle of blocking and associated physical mechanisms in the Australian region and relationship with rainfall |
title_full |
The seasonal cycle of blocking and associated physical mechanisms in the Australian region and relationship with rainfall |
title_fullStr |
The seasonal cycle of blocking and associated physical mechanisms in the Australian region and relationship with rainfall |
title_full_unstemmed |
The seasonal cycle of blocking and associated physical mechanisms in the Australian region and relationship with rainfall |
title_sort |
seasonal cycle of blocking and associated physical mechanisms in the australian region and relationship with rainfall |
publisher |
Amer Meteorological Soc |
publishDate |
2013 |
url |
https://doi.org/10.1175/MWR-D-13-00040.1 http://ecite.utas.edu.au/119090 |
geographic |
Antarctic Southern Ocean Austral |
geographic_facet |
Antarctic Southern Ocean Austral |
genre |
Antarc* Antarctic Antarctica Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctica Southern Ocean |
op_relation |
http://ecite.utas.edu.au/119090/1/The Seasonal Cycle of Blocking.pdf http://dx.doi.org/10.1175/MWR-D-13-00040.1 Pook, MJ and Risbey, JS and McIntosh, PC and Ummenhofer, CC and Marshall, AG and Meyers, GA, The seasonal cycle of blocking and associated physical mechanisms in the Australian region and relationship with rainfall, Monthly Weather Review, 141, (12) pp. 4534-4553. ISSN 0027-0644 (2013) [Refereed Article] http://ecite.utas.edu.au/119090 |
op_doi |
https://doi.org/10.1175/MWR-D-13-00040.1 |
container_title |
Monthly Weather Review |
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141 |
container_issue |
12 |
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4534 |
op_container_end_page |
4553 |
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1766250716702179328 |