Wind Erosion in Western Queensland Australia

Chapter 3 – Modelling Land Erodibility Reviewscales, and in particular there is a significant lack of modelling research at the landscape scale(i.e. ~10 3 km 2 ).A number of common challenges and limitations have emerged in representing landerodibility in wind erosion models. The first of these represents arguably the greatestchallenge in wind erosion modelling, and affects the accuracy of model representations ofland susceptibility to wind erosion. They include (after Raupach and Lu, 2004):• Reliability of control representations and ability to account for soil erodibility dynamics;• The availability of suitable input data;• Up-scaling models and accounting for sub-grid scale heterogeneity; and• Validation of regional to global scale models.3.5.1 Reliability of Control RepresentationsThe reliability of how controls are represented in wind erosion models has been affected by:1) a lack of research into the temporal dynamics of soil erodibility, and 2) our ability toaccount for sub-grid scale variations in soil and land surface conditions, in particular theheterogeneous distribution of surface roughness. The effects of sub-grid scale heterogeneityon model performance are described in Section 3.5.3.Raupach and Lu (2004) note that deficiencies in dust source parameterisations account for alarge part of the observed discrepancies in model estimations of dust emissions. The accuraterepresentation of spatial and temporal patterns in land erodibility is therefore essential forgood model performance. While field scale models, for example WEQ, RWEQ, WEPS,contain factors to account for and simulate changes in soil erodibility, such factors have notbeen integrated into the regional to global scale models (Zobeck et al., 2003). These modelsaccount for spatial variations in soil erodibility by estimating u *t as a function of the soilparticle size distribution (e.g. Marticorena and Bergametti, 1995) and/or by designatingregional dust source areas using topographic, geomorphic or remote sensing based indicators(e.g. Ginoux et al., 2001; Grini et al., 2005). The rationale for omitting soil erodibility factorsfrom these broad-scale models is that robust models to simulate temporal changes in soilaggregation and crusting simply do not exist (Shao, 2000). Empirical models, like that used93