@InProceedings{DurrantPezzSimmSmit:2006:AsSoAu,
author = "Durrant, Thomas Hawkins and Pezza, Alexandre Bernandes and
Simmonds, Ian and Smith, Ian",
affiliation = "The University of Melbourne, Parkville VIC 3010, Australia
(Durrant and Pezza)",
title = "Sea ice extension around Antarctica: Association with southern
Australian rainfall via changes in Southern Hemisphere cyclone and
anticyclone behaviour",
booktitle = "Proceedings...",
year = "2006",
editor = "Vera, Carolina and Nobre, Carlos",
pages = "189--194",
organization = "International Conference on Southern Hemisphere Meteorology and
Oceanography, 8. (ICSHMO).",
publisher = "American Meteorological Society (AMS)",
address = "45 Beacon Hill Road, Boston, MA, USA",
keywords = "Antarctic sea ice, australian rainfall, Southern Hemsiphere
circulation.",
abstract = "Interactions occurring over the Southern Ocean between the
Antarctic sea ice, the atmosphere and the ocean form a vastly
complex system. The sparsity of data available over this region
has traditionally greatly inhibited the study of this system, a
short-falling which has been significantly improved in recent
times by the advent of computer and satellite technology.
Understanding of Antarctic sea ice and its interactions with the
Southern Ocean circulation is of particular interest in Australia
due to its proximity to the south Australian coast and potential
influences on Australian climate. The aim of this study is to
explore the relationship and possible connection between Antarctic
sea ice extent and rainfall in southern Australia. An initial
statistics component examines correlations between sea ice extent
and rainfall in both Melbourne and Perth, guiding later work
investigating associated changes in regional cyclone and
anticyclone behaviour. Although this relationship between sea ice
extent and southern ocean circulation has been the subject of a
number of studies, this is the first detailed analysis performed
focussing on the Australian region. The study is performed for the
period for which reliable remotely sensed sea ice data is
available, namely 1979-2003. Correlations between Perth (located
on the west coast) and Melbourne (east coast) rainfall data and
sea ice extent data suggest that these two quantities are
inversely related, with high sea ice extent associated with low
rainfall and vice versa. Dividing the ice pack into five roughly
equal longitudinal sectors, local and slightly upstream sectors
appear more influential in the Australian region than the pack
considered as a whole, specifically, the Indian Ocean sector is
most associated with Perth rainfall, while that of Melbourne is
related to the West Pacific sector. Furthermore, results suggest
the strongest association occurs in winter. The Melbourne
University Cyclone Tracking Scheme is employed to investigate
associated changes in regional cyclone and anticyclone behaviour,
analysing the NCEP2 reanalysis data set over the same period. The
track statistics of system density and system depth (a measure of
system strength) are analysed for composites of years when the sea
ice is high and low for both the Indian and West Pacific sectors
in winter. Generally, low (high) sea ice is associated with
increased (decreased) cyclone system density over regions of
southern Australia. This suggests physical agreement with the
observed negative correlations between ice and rainfall in
Melbourne and Perth, given that regions of increased cyclone
system density are likely to receive more rainfall. Depth
anomalies showed consistent patterns, with strong anomalous areas
appearing over the Southern Ocean in areas of cyclone paths
associated with frontal systems affecting Australia. Anticyclone
patterns are in agreement and compliment what was found for the
cyclones. Furthermore, results were consistent with the
correlations regarding specific regions of influence, adding
weight to these findings and overall providing a coherent physical
mechanism for the observed connection. It is not possible from
this kind of analysis to infer if the ice is driving these
circulation changes, or being driven by them.",
conference-location = "Foz do Igua{\c{c}}u",
conference-year = "24-28 Apr. 2006",
language = "en",
organisation = "American Meteorological Society (AMS)",
ibi = "cptec.inpe.br/adm_conf/2005/10.07.01.54",
url = "http://urlib.net/ibi/cptec.inpe.br/adm_conf/2005/10.07.01.54",
targetfile = "189-194.pdf",
type = "Climate and Cryosphere of the Antarctic region",
urlaccessdate = "16 jun. 2024"
}