Regional climate simulation over Australia's Murray-Darling basin: A multitemporal assessment

The climate of the Murray-Darling basin (MDB) has been simulated using the Weather Research and Forecasting (WRF) model. WRF was implemented using a 10 km horizontal grid and run for 24 years from 1985 through 2008. The model simulated climate was evaluated against gridded precipitation and temperature observations from the Australian Water Availability Project (AWAP) at daily, monthly, interannual and multiannual time scales. WRF successfully reproduced daily statistics when compared to AWAP observations. It also improves almost all monthly and interannual statistics relative to those of the National Oceanic and Atmospheric Administrations Centers for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) Reanalysis, which supplied the lateral boundary conditions. WRF simulations were able to capture the drought experienced over the basin in recent years, except for an overestimation of the negative anomaly in the northernmost part of the domain. Examining ENSO cycles showed WRF has good skill at capturing the correct spatial distribution of precipitation anomalies associated with El Nio/La Nia events during this 24 year period. The high-resolution simulation developed here allows for improved characterization of land-atmosphere coupling within the basin, including identification of the dominant water vapor source regions for events and seasons and provides insight into the quantification of precipitation recycling.