Wind Erosion in Western Queensland Australia

Chapter 5 – Land Erodibility Model DevelopmentRemoving dust hazes and whirls from the western stations records has little effect on thefrequencies, indicating that the majority of events recorded at these stations are dust storms(i.e. Synop Codes 09, 30-35) or locally blowing dust (Code 07). At the eastern stationsremoving hazes and whirls significantly reduces the remaining event frequencies, indicatingthat the majority of events recorded at these stations are non-local (i.e. hazes) or are notrepresentative of lateral wind erosion activity (i.e. dust whirls).Figure 5.5 presents examples of time-series trajectories of mean annual land erodibility forQuilpie, Thargomindah and Windorah. Figure 5.5a presents trajectories for the circular AOIsat scales from 25 to 150 km. Figure 5.5b presents trajectories extracted from the directionalhalf-circle AOIs with a radius of 100 km. The patterns in trajectory changes between scales inFigure 5.5a are typical of those found across all stations. Differences were found between themagnitude of output values between scales, but no consistent differences were found betweenthe trends in the trajectories. Data for the year 1980 at the 150 km scale for Quilpie andThargomindah (5.5a), for example, indicate that land further from these stations had lowerodibility during that year. Variations in mean annual output values for the directional halfcircleAOIs also exhibit significant differences in magnitude and not trajectory. The trends inmean annual land erodibility extracted from model output on one side of a station (i.e. to thewest) were found to be similar to those extracted from other areas around the stations (i.e. tothe north, east or south). This outcome is interesting as the BoM stations are surrounded bymultiple soil and vegetation types so the land erodibility trajectories could be expected tohave different trends.147