Wind Erosion in Western Queensland Australia

Chapter 7 – Land Erodibility Dynamics 1980-2006A cross-correlation analysis was used to investigate the presence and strength of relationshipsbetween mean annual land erodibility and annual total rainfall averaged across the four studyarea bioregions, and two indicators of the condition of ENSO and the PDO. The TroupSouthern Oscillation Index (SOI) was used in the analysis as a measure of ENSOfluctuations. The Troup SOI data were obtained from the Australian Government Bureau ofMeteorology (BoM, 2007b) and represent the standardised anomaly of the Mean Sea LevelPressure difference between Tahiti and Darwin (Troup, 1965). Monthly PDO Index data(JISAO, 2007) were used to define PDO phases and represent the first principal componentof monthly sea surface temperature variability in the North Pacific Ocean (Mantua et al.,1997). All data were converted to annual averages for the correlation analysis.7.5 ResultsFigure 7.2 presents mean annual land erodibility assessments for western Queensland from1980 to 2006. The following sections analyse patterns in mean monthly model output and thedata presented in Figure 7.2. First, spatial patterns in land erodibility are described. Temporalpatterns in land erodibility dynamics are then resolved at seasonal and inter-annual timescales.7.5.1 Spatial Patterns in Land ErodibilityFigure 7.3 summarises spatial patterns in land erodibility in western Queensland. Threeregions of the study area have consistently high land erodibility. These include the MulgaLands, Strzelecki Desert, and western side of the Channel Country (Figure 7.1). In the MulgaLands high erodibility land occurs in the mulga (Acacia aneura) plains east of the BullooRiver between Quilpie and Thargomindah (Figure 1.3). This region extends into the flood-outcountry and dunefields to the south of the Bulloo River, and across into the Strzelecki Desertdunefields. A third region of high erodibility land lies between Birdsville and Urandangiealong the outer-floodplains of the Georgina and Diamantina Rivers. The climates of the areaswith consistently high land erodibility are similar. These areas receive