Wind Erosion in Western Queensland Australia

Chapter 8 – Conclusionsmodels are not dissimilar. Maps of u *t and land erodibility modelled by Lu (1999) andAUSLEM for western Queensland show similarities across the Channel Country. It would beconstructive to compare the assessments in cross-model validation exercises. Themethodology for collecting field surveys of land erodibility described in Chapter 6 wouldsupport these comparisons and provide additional data for validating models like IWEMS.Finally, this research has clearly demonstrated the requirement for further studies to assessspatial and temporal patterns in land susceptibility to wind erosion. Dynamic changes in landerodibility like those identified by AUSLEM must be considered in the context of modellingregional to global scale dust emission and transport (e.g. Mahowald et al., 2003a). Grini et al.(2005) sought to identify suitable methods for characterising erodibility patterns in globaldust source areas. The frameworks for modelling soil and land erodibility presented in thisthesis support that research, and there is significant potential for integrating the methods andfindings of this research into such studies.8.4 Research LimitationsThe major limitations of this research relate to three main areas. They are: 1) the availabilityof robust models to predict temporal changes in soil erodibility, and the lack of quantitativedata with which to parameterise such models; 2) spatial scale effects on model performancein heterogeneous landscapes; and 3) the availability of data suitable for model validation.1. The accuracy of AUSLEM at spatial scales less than ~50 km 2 was severely affected bythe absence of a robust scheme to predict temporal changes in soil erodibility. This issuebecame evident when analysing trends in the model output at locations with similarvegetation cover but different soil textural attributes (Chapter 5). Analysis of the modeloutput was therefore restricted to the landscape (10 3 km 2 ) to regional (10 4 km 2 ) scales.While AUSLEM output accuracy at smaller scales is affected by the accuracy of itsAussie GRASS inputs, the addition of a soil erodibility scheme is likely to significantlyimprove model performance. It would also allow for the analysis of model output at timescales less than one month, at which variations in soil erodibility are an important controlon land erodibility dynamics.198