Land cover change as an additional forcing to explain the rainfall decline in the south west of Australia

Abstract

A fully coupled climate model forced with natural and anthropogenic atmospheric forcings is used to investigate the rainfall decline in the south west of Australia. Results are compared between experiments with two different land covers. We found that vegetation cover affects modelled rainfall in the region and enhances the model response to anthropogenic atmospheric forcings, which were found in a previous study to explain part of the observed rainfall decline. This result is observed directly in model rainfall and using a statistical downscaling technique which relates local rainfall to mean sea level pressure and large-scale rainfall. While the rainfall response to anthropogenic forcings is driven mostly by the changes in pressure, the land cover influences directly the modelled rainfall (large-scale and total) and thus indirectly the downscaled rainfall. Copyright 2006 by the American Geophysical Union.