Changes in summer rainfall and implications for agriculture : final report B.CCH.2111

Abstract

Annual and seasonal rainfall are important drivers of agricultural productivity and profitability in Australian agriculture and various climatological and synoptic drivers influence rainfall patterns in Australia’s diverse climate. This study detects trends in past and future annual, seasonal and extreme rainfall across three important agricultural production regions in the Australian midlatitudes, using station and gridded data for the 1907 to 2018 period. Apart from region-wide changes, we find a positive trend in summer rainfall for two of the seventeen studied locations and a negative trend in winter rainfall for five of the seventeen locations. There is some indication of an increase in the number of very wet days and the number of days with heavy precipitation in the Northern Murray Darling Basin, and a decrease in the number of consecutive wet days in the coastal regions of Queensland and New South Wales and the Western Australia Wheat Belt. These patterns suggest a change of how rainfall is distributed over the year and a potential increase in rainfall intensity between 1907 and 2013.This project was commissioned and funded by MLA, GRDC, CRDC, Sugar Research Australia and AgriFutures Australia through the Managing Climate Variability Program Phase 5 project.