Objective identification of wind change timing from single station observations Part 2: towards the concept of a wind change climatology

Wind changes, and particularly wind changes that are associated with dry cold fronts, have profound effects on fire behaviour and fire-fighting operations (e.g. Cheney et al. 2001). Huang and Mills (2006b) (hereafter Part 1) have reported on the first stage of a larger scale project that aims to improve the understanding and prediction of wind changes in Australia. In Part 1 a method of objectively identifying the ‘change time’ at an observing station on a day when a significant frontal wind change was forecast by the Victorian Regional Forecast Centre (VRFC) of the Australian Bureau of Meteorology (the Bureau) was described. The method uses fuzzy logic based on time series of METAR and SPECI observations from a single station, and was shown to have comparable performance to subjective methods based on space-time continuity of synoptic analyses. The objective method also produces start time and end time of the change period, rather than just a single ‘change time’, as well as the interval during the change period where the ‘Wind Change Rate Index’ (WCRI) exceeds a specified threshold. Aust. Met. Mag. 55 (2006) 275-288