Weather Radar Information and Distributed Hydrological Modelling (Proceedings of symposium HS03 held during IUGG2003 at Sapporo, July 2003). IAHS Publ. no. 282, 2003. p. 315–320.

1 School of Mathematics, The University of New South Wales, Sydney, New South Wales 2052, Australia

2 Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China

3 Bureau of Meteorology, Sydney, New South Wales, Australia

4 Rural Fire Office, New South Wales, Australia

Abstract An advanced soil moisture scheme (Richards) is coupled to a high resolution numerical weather prediction model (HIRES) replacing the original Force–Restore scheme and changing other related processes. The new scheme now provides HIRES with an upper and lower bound for soil moisture through a process of checking model precipitation that is used to calculate soil moisture. A comparison of HIRES model results is presented using the new and original soil moisture schemes applied to the Goulburn River catchment in southeastern Australia. It is shown that precipitation is the most important factor to be considered before introducing an advanced scheme to correctly simulate soil moisture. It is also shown that, based on the correct precipitation input, the Richards scheme provides a more realistic soil moisture profile. Improving model soil moisture will ultimately provide better estimates of forest fire danger indices used as guidance by weather forecasters in assessing bushfire risk.

Key words bushfire; forest fire danger index; Goulburn River catchment, Australia; numerical modelling; soil moisture