NARCliM1.5 projections over the southern Murray�Darling Basin, Australia

Abstract

: The NSW Department of Planning and Environment (DPE) is undertaking a risk-based methodology to account for climate variability and change in developing its regional water strategies. As part of this process, historical biases and future changes associated with 6 model variants from NARCliM1.5 simulations have been analysed. This paper presents results for two future time windows centered on 2030 and 2070, for scenarios RCP 4.5 and RCP 8.5 for the southern basin region (which includes the Murrumbidgee, Murray and Snowy catchments as well as regions of Victoria and South Australia), focusing on the hydrologically relevant attributes of precipitation. The evaluation of NARCliM1.5 has been made for model ensemble averages with respect to gauged data in the southern basin for two cases, (1) GCM runs forced with historical greenhouse gas forcings (‘historical runs’) over the period 1951 to 2005, and (2) reanalysis runs (‘evaluation runs’) for the period 1979-2013. The NARCliM1.5 projections were analysed for two 30-year time windows centered on 2030 and 2070 respectively. The range of grid level future changes projected by the NARCliM1.5 ensemble mean are not outside the ranges projected by other sources of climate projections.