Wind Erosion in Western Queensland Australia

More documents

Recommendations

Info

Chapter 5 – Land Erodibility Model Developmentwind erosion in marginal farming lands (Leys, 1999). Studies reporting the location of areassusceptible to wind erosion have foundations in land degradation surveys, analysis of duststorm frequencies and aerosol indices derived from satellite imagery, or present static erosionhazard maps based on soil texture or wind run. These methods have been applied extensivelyin Africa, North America, Europe, the Middle East and China (e.g. Lynch and Edwards,1980; Kalma et al., 1988; Mezösi and Szatmári, 1998; Prospero et al., 2002; Shi et al., 2004).An important limitation of these methods is that they have not provided a means for assessingdynamic changes in land susceptibility to wind erosion at scales between the field and coarserregional scales (10 4 km 2 ). In Australia reports of the extent of wind erosion have beenproduced from assessments of landscape condition during land degradation episodes (e.g.Ratcliffe, 1937, Carter, 1985). The survey methods tend to provide snapshots of erosionhazard which reflect the regional climate at the time of survey (i.e. drought), and may notaccount for spatial and temporal variability in erosion controls. While numerous wind erosionmodelling systems have been developed, rarely have the models been applied with theexpress purpose of monitoring spatio-temporal variability in areas susceptible to winderosion. This variability can be captured through modelling and is critical for identifyingwind erosion “hot spots” that are significant dust emitters (Gillette, 1999).The development of models to assess land susceptibility to wind erosion should be seen asbeing essential to supporting decisions about the management of dryland environments (e.g.Bhuyan et al., 2002; Bowker et al., 2006). This also applies to the development andapplication of models to assess water erosion (e.g. Berlekamp et al., 2007; Miller et al.,2007). Modelling provides the opportunity to examine spatial and temporal patterns inerosion dynamics within landscapes, at different spatial and temporal resolutions and acrossscales. Spatially distributed models can be used to establish benchmarks of historicalvariations in the landscape response to climate variability and land management pressures,and to provide measures of the sensitivity of landscapes and waterways to climate and landmanagement changes (Tegen and Fung, 1995; Baigorria and Romero, 2007). These are bothrequirements for enhancing land management policy. The need for research of this nature isgrowing, especially in sub-tropical environments in which rainfall amounts and variability,that control erosion processes, are expected to be affected by future climate change (Meehl etal., 2007).130
Chapter 5 – Land Erodibility Model DevelopmentThe development of models provides a means for assessing and extending our understandingof wind erosion processes across multiple spatial and temporal scales. There are fewaccessible methods for modelling or mapping spatio-temporal patterns of wind erosionhazard in Australia at moderate to high spatio-temporal resolutions (< 10 3 km 2 ; daily –monthly). The development of the Integrated Wind Erosion Modelling System (IWEMS) hasprovided a resource for addressing this deficiency, but the model is currently only applicableat a moderate (5 x 5 km) spatial resolution within south-eastern Australia (Lu and Shao,2001). Webb et al. (2006) presented a spatially explicit Australian Land Erodibility Model(AUSLEM) for predicting land susceptibility to wind erosion. The model was applied at a 5 x5 km spatial resolution on a monthly time-step across Australia. Qualitative comparisons ofmodel output with an index of wind erosion activity indicated that the model could hind-casterosion hazard with a reasonable level of success. However, the model used a thresholdbasedrule-set which tended to bias output predictions toward areas situated in a small rangeof soil textures.This chapter addresses the limitations of the AUSLEM rule-based modelling system byderiving a new scheme to predict land erodibility. The chapter presents a description of therevised land erodibility model and evaluates model performance through a comparison ofoutput and observational records of wind erosion activity. The focus of this research was todevelop AUSLEM to predict land susceptibility to wind erosion in western Queensland,Australia.5.2 Study AreaAnalyses of long term dust-event frequencies in Australia indicate that the eastern half of thecontinent is the most active wind erosion region (McTainsh et al. 1990). Model developmentand validation were carried out for the northern part of this region, in western Queensland.Figure 5.1 provides a map of the study area, as described in Chapter 1, Section 1.6. The mapshows the extent of the four bioregions covering the western Queensland rangelands and thelocation of meteorological stations from which observational records of dust events, used inthis chapter, were acquired. Wind erosion is infrequently observed to the east of the studyarea due to higher annual rainfall and vegetation cover, so that area is not considered here.131
Page 1:
Modelling Land Susceptibility toWin
Page 4:
AUSLEM was developed as a Geographi
Page 8 and 9:
who joined me on many trips, shared
Page 10 and 11:
Conference Presentations by the Aut
Page 12 and 13:
2.2.5 Soil Moisture Effects........
Page 14 and 15:
Chapter 6: Assessing Land Susceptib
Page 16 and 17:
List of FiguresChapter 1: Introduct
Page 18 and 19:
Figure 2.11 Conceptual model of lan
Page 20 and 21:
hand column) presents trajectories
Page 22 and 23:
List of TablesChapter 1: Introducti
Page 24 and 25:
xxii
Page 26 and 27:
Chapter 1 - Introduction• The abi
Page 28 and 29:
Chapter 1 - Introductionchapter the
Page 30 and 31:
Chapter 1 - Introductionevents yr -
Page 32 and 33:
Chapter 1 - IntroductionFigure 1.2
Page 34 and 35:
Chapter 1 - Introductionsusceptibil
Page 36 and 37:
Chapter 1 - Introductiontemporal pa
Page 38 and 39:
Chapter 1 - Introduction1.5 Researc
Page 40 and 41:
Chapter 1 - IntroductionFigure 1.3
Page 42 and 43:
Chapter 1 - IntroductionMitchell Gr
Page 44 and 45:
Chapter 1 - IntroductionSimpson-Str
Page 46 and 47:
Chapter 1 - IntroductionDowns. Wind
Page 48 and 49:
Chapter 1 - IntroductionChapter 2 p
Page 50 and 51:
Chapter 2 - Land Erodibility Contro
Page 52 and 53:
Page 54 and 55:
Page 56 and 57:
Page 58 and 59:
Page 60 and 61:
Page 62 and 63:
Page 64 and 65:
Page 66 and 67:
Page 68 and 69:
Page 70 and 71:
Page 72 and 73:
Page 74 and 75:
Page 76 and 77:
Page 78 and 79:
Page 80 and 81:
Page 82 and 83:
Page 84 and 85:
Page 86 and 87:
Page 88 and 89:
Page 90 and 91:
Page 93 and 94:
Chapter 3 - Modelling Land Erodibil
Page 95 and 96:
Page 97 and 98:
Page 99 and 100:
Page 101 and 102:
Page 103 and 104: Chapter 3 - Modelling Land Erodibil
Page 121: Chapter 3 - Modelling Land Erodibil
Page 124 and 125: Chapter 4 -Modelling Soil Erodibili
Page 156 and 157: Chapter 5 - Land Erodibility Model
Page 182 and 183: Chapter 6 - Field Assessments and M
Page 192 and 193: Chapter 7 - Land Erodibility Dynami
Page 204 and 205:
Chapter 7 - Land Erodibility Dynami
Page 206 and 207:
Page 208 and 209:
Page 210 and 211:
Page 212 and 213:
Page 214 and 215:
Chapter 8 - Conclusions• There is
Page 216 and 217:
Chapter 8 - ConclusionsThe third ai
Page 218 and 219:
Chapter 8 - Conclusionswas shown to
Page 220 and 221:
Chapter 8 - Conclusionsland use cha
Page 222 and 223:
Chapter 8 - Conclusionsmodels are n
Page 224 and 225:
Chapter 8 - Conclusionsmultiple ass
Page 226 and 227:
Chapter 8 - Conclusionsthe opportun
Page 228 and 229:
Beadle, N.C.W., 1945. Dust storms.
Page 230 and 231:
Bryan, R.B., Govers, G., Poesen, J.
Page 232 and 233:
Chepil, W.S., 1965. Transport of so
Page 234 and 235:
Fryrear, D.W., Sutherland, P.L., Da
Page 236 and 237:
Gregory, J.M., 1984. Prediction of
Page 238 and 239:
Hugenholtz, C.H., Wolfe, S.A., 2005
Page 240 and 241:
Littleboy, M., McKeon, G.M., 1997.
Page 242 and 243:
Marshall, J.K., 1973. Drought, land
Page 244 and 245:
Assessment Report of the Intergover
Page 246 and 247:
Penner, J.E., et al. , 2001. Climat
Page 248 and 249:
Rickert, K.G., McKeon, G.M., 1982.
Page 250 and 251:
Stokes, C., J., McAllister, R.R.J.,
Page 252 and 253:
Williams, W.J., Eldridge, D.J., Alc
show all

Wind Erosion in Western Queensland Australia

Create successful ePaper yourself

Delete template?

Save as template?