Changes in frequency and location of east coast low pressure systems affecting southeast Australia

Speer, M; Leslie, L; Hartigan, J; Macnamara, S

Changes in frequency and location of east coast low pressure systems affecting southeast Australia

Speer, M

Leslie, L

Hartigan, J

Macnamara, S

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Publisher:: MDPI AG
Publication Type:: Journal Article
Citation:: Climate, 2021, 9, (3), pp. 1-21
Issue Date:: 2021-03-01

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Field	Value	Language
dc.contributor.author	Speer, M https://orcid.org/0000-0003-0421-7744
dc.contributor.author	Leslie, L https://orcid.org/0000-0001-5616-2330
dc.contributor.author	Hartigan, J https://orcid.org/0000-0002-7783-9440
dc.contributor.author	Macnamara, S
dc.date.accessioned	2022-01-22T22:30:29Z
dc.date.available	2022-01-22T22:30:29Z
dc.date.issued	2021-03-01
dc.identifier.citation	Climate, 2021, 9, (3), pp. 1-21
dc.identifier.issn	2225-1154
dc.identifier.issn	2225-1154
dc.identifier.uri	http://hdl.handle.net/10453/153442
dc.description.abstract	Low pressure systems off the southeast coast of Australia can generate intense rainfall and associated flooding, destructive winds, and coastal erosion, particularly during the cool season (April–September). Impacts depend on coastal proximity, strength and latitude. Therefore, it is important to investigate changes in frequency, duration, location, and intensity of these systems. First, an existing observation‐based database of these low pressure systems, for 1970–2006, is extended to 2019, focusing on April–September and using archived Australian Bureau of Meteorology MSLP charts. Second, data consistency between 1970 and 2006 and 2007 and 2019 is confirmed. Third, permutation testing is performed on differences in means and variances between the two 25‐year intervals 1970–1994 and 1995–2019. Additionally, trends in positions, durations and central pressures of the systems are investigated. p‐values from permutation tests reveal statistically significant increases in mean low pressure system frequencies. Specifically, a greater frequency of both total days and initial development days only, occurred in the latter period. Statistically significant lower variance for both latitude and longitude in systems that developed in both subtropical easterly and mid‐latitude westerly wind regimes indicate a shift south and east in the latter period. Furthermore, statistically significant differences in variance of development location of explosive low pressure systems that develop in a low level easterly wind regime indicate a shift further south and east. These changes are consistent with fewer systems projected to impact the east coast. Finally, important changes are suggested in the large scale atmospheric dynamics of the eastern Australian/Tasman Sea region.
dc.language	en
dc.publisher	MDPI AG
dc.relation.ispartof	Climate
dc.relation.isbasedon	10.3390/cli9030044
dc.rights	info:eu-repo/semantics/openAccess
dc.title	Changes in frequency and location of east coast low pressure systems affecting southeast Australia
dc.type	Journal Article
utslib.citation.volume	9
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Mathematical and Physical Sciences
utslib.copyright.status	open_access	*
dc.date.updated	2022-01-22T22:30:21Z
pubs.issue	3
pubs.publication-status	Published
pubs.volume	9
utslib.citation.issue	3

Abstract:

Low pressure systems off the southeast coast of Australia can generate intense rainfall and associated flooding, destructive winds, and coastal erosion, particularly during the cool season (April–September). Impacts depend on coastal proximity, strength and latitude. Therefore, it is important to investigate changes in frequency, duration, location, and intensity of these systems. First, an existing observation‐based database of these low pressure systems, for 1970–2006, is extended to 2019, focusing on April–September and using archived Australian Bureau of Meteorology MSLP charts. Second, data consistency between 1970 and 2006 and 2007 and 2019 is confirmed. Third, permutation testing is performed on differences in means and variances between the two 25‐year intervals 1970–1994 and 1995–2019. Additionally, trends in positions, durations and central pressures of the systems are investigated. p‐values from permutation tests reveal statistically significant increases in mean low pressure system frequencies. Specifically, a greater frequency of both total days and initial development days only, occurred in the latter period. Statistically significant lower variance for both latitude and longitude in systems that developed in both subtropical easterly and mid‐latitude westerly wind regimes indicate a shift south and east in the latter period. Furthermore, statistically significant differences in variance of development location of explosive low pressure systems that develop in a low level easterly wind regime indicate a shift further south and east. These changes are consistent with fewer systems projected to impact the east coast. Finally, important changes are suggested in the large scale atmospheric dynamics of the eastern Australian/Tasman Sea region.

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http://hdl.handle.net/10453/153442