The atmospheric water balance over the Murray-Darling Basin, based on numerical weather prediction output

The hydroclimate of the Murray-Darling Basin in southeast Australia has been investigated by estimating the Basin’s atmospheric water balance, based on numerical weather prediction (NWP) output. The water balance has been calculated for the period from 2000 to 2004, using archived output from the Australian Bureau of Meteorology’s mesoscale model, the Limited Area Prediction System (LAPS). The central goal of this work was to characterise the Basin’s atmospheric water balance, based on LAPS output. A parallel goal was to assess the ability of LAPS to generate viable and accurate water balances. This was necessary due the scarcity of previous work in this field in Australia (or other similarly arid regions), and due also to previous international studies having concluded that balance equations based on NWP model output contain systematic errors. The climate of the Murray-Darling Basin is arid, and was unusually dry for most of the study period, which included the severe drought of 2002, followed by an extended period of below average rainfall. The results of this study are therefore more relevant to dry