Interdecadal modulation of Australian Rainfall
J. M. Arblaster, G. A. Meehl
National Center for Atmospheric Research, Boulder, Colorado
A. M. Moore
Program in Atomspheric and Oceanic Sciences, University of Colorado
Interdecadal variability is investigated in the 300 year control run of the
Parallel Climate Model, a global coupled atmosphere-land-ocean-sea ice model.
The model is found to produce interdecadal characteristics similar to those
observed, both in frequency, spatial patterns and amplitude. Modulation of
Australian climate on interdecadal time scales is found to have contributions
from both the interdecadal modulation of ENSO and western Pacific SSTs. A
slackening of the equatorial Pacific thermocline slope contributes to diminished
ENSO variability during positive interdecadal periods. These changes to ENSO and
shifts in the position of the Walker circulation are examined as physical
mechanisms that lead to the weakened correlations between the SOI and Australian
climate during positive interdecadal periods. Warm anomalies in the western
Pacific also contribute to a decrease in Australian rainfall in the model.
Back to Publications List
Hongjun Zhang:
zhangho@ucar.edu