LOCAL TO LONG-RANGE DUST TRANSPORT OVER CENTRAL EASTERN AUSTRALIA - Advances in Geosciences - page 29

LOCAL TO LONG-RANGE DUST TRANSPORT OVER
CENTRAL EASTERN AUSTRALIA
MILTON S. SPEER ∗,‡ and LANCE M. LESLIE †,§
∗ Bureau of Meteorology, Sydney, Australia
† School of Meteorology, The University of Oklahoma, Norman, OK, USA
‡ [e-mail]
§ [e-mail]
A climatology of dust reporting days from 1995 to February 2004 has been
prepared for the central eastern Australia region. The climatology reveals a
total of 55 “dust days,” consisting of 43 dust days associated with fronts.
Of these 24 were classified as being embedded in the zonal westerlies in the
Great Australian Bight (GAB) or in westerlies produced by from low-pressure
systems in the GAB. The remaining 19 were associated with fronts over eastern
Australia where high pressure systems in the GAB generated postfrontal south
to southeast winds. Two case studies of dust storm generation and transport
were modeled using an integrated wind erosion prediction system. The model
predictions were broadly consistent with both satellite images highlighting dust
and with the synoptic observations that reported dust.
1. Introduction
The local or long -range transport of dust by wind erosion, events most
commonly referred to as dust storms (in some regional areas they are
called dust devils), are a regular occurrence over much of central east-
ern Australia. McTainsh and Pitblado 1 showed that annual dust storm
frequencies over Australia for the period 1957-1984 can be as high as
5-10 times per year in some areas. Ekstrom et al. 2 divided Australian
dust storms into two groups with distinct dust storm seasons, namely,
spring-summer (September-February), and summer-autumn (December-
May). Dust storms can be further subdivided into two types; those that
result in the local dust transport and those that produce long-range dust
transport. Local dust transport typically occurs over periods ranging from
a few minutes to a few hours as a result of short-lived, extreme wind speeds
generated from thunderstorms or dust devils.
Long-range dust transport occurs on longer time scales and on spatial
scales ranging from hundreds to thousands of kilometres usually with the
passage of a frontal system. In these prolonged dust storm episodes wind
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