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  • F.S. Mpelasoka, M.A. Collier, R. Suppiah and J. Peña Arancibia, 2007: Application of Palmer Drought Severity Index to Observed and Enhanced Greenhouse Conditions using CSIRO Mk3 GCM Simulations. MODSIM07 conference, 7.

During the past century some parts of Australia
have experienced extended severe droughts
affecting Australia’s landscape, agricultural
production and water resources. In addition, recent
studies by CSIRO show that most Global Climate
Models simulate decreases in future mean rainfall
for most areas in Australia, with increases in
variability and near-surface air temperature under
enhanced greenhouse conditions. The erratic
change in climate is likely to be visible in the cycle
and intensity of extreme events such as droughts.
In this study, first, we investigate spatial and
temporal characteristics of drought duration,
frequency and severity over Australia using Palmer
Drought Severity Index (PDSI) from 1951 to 2004.
Second, we applied the PDSI to the 20th century,
the committed climate change (commit) and the
Special Report for Emissions (SRES) A2
experiments of CSIRO Mk3.5 GCM for the period
2051 to 2100. The basic boundary conditions for
the three experiments are described by Meehl et al.
(2005). The results showed that the CSIRO Mk3
GCM generally captures most of the characteristics
of the observed drought events, except for
relatively low spatial correlations. This can be
attributed to spatial scale resolution mismatch
between the model and observations. Figure 1
depicts PDSI time-series over four selected sites
for 1951-2000 and 2051-2100. The frequency of
periods with PDSI < 0 in the top panel of Figure 1
demonstrates the venerability of Australia to
droughts. Under enhanced greenhouse conditions
the model shows an increase in drought relative
frequency, intensity and duration of droughts,
particularly droughts defined by PDSI < -2
(moderate to severe droughts). Examples of
drastic changes in severe drought characteristics
are given in Table 1. Differences between commit
and A2 simulations quantify the response to
transient increase in anthropogenic greenhouse
forcing through the 21st century. Changes in
drought characteristics potentially have major
implications for natural resource management,
water security planning, water demand
management strategies and drought relief

Full Article: http://www.mssanz.org.au/MODSIM07/papers/10_s61/ApplicationOfPalmer_s61_Mpelasoka_.pdf

Last Updated: 2008-05-12

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