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EVALUATION OF DROUGHT LEVEL AND ANTHROPOGENIC LAND USE IMPACT ON DUST EMISSION IN SOUTHWESTERN UNITED STATES: QUANTITATIVE AND SPATIO-TEMPORAL ANALYSIS OF DUST POINT SOURCES
  • Tarek Kandakji,
  • Thomas E. Gill,
  • Jeff Lee
Tarek Kandakji
Texas Tech University

Corresponding Author:tareqkun@gmail.com

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Thomas E. Gill
University of Texas at El Paso
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Jeff Lee
Texas Tech University
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Abstract

Quantifying the effect of anthropogenic land use change on dust emission is a contentious issue. In this research, 1508 dust point sources were detected in the Southern High Plains and Chihuahuan Desert regions of the United States for 2001-2016, encompassing a period of extreme drought. These points were subjected to quantitative and spatio-temporal analysis. Point pattern analysis showed a significant cluster of these points in West Texas (Nearest Neighbor Ratio = 0.33, р < 0.001) where cultivated lands and grasslands are dominant land cover. Spatial observation suggests that the geographic center of dust points in these regions shifts away from bare soil and shrublands toward grasslands and cultivated lands as drought level increases, while it shifts away from grasslands and cultivated lands towards bare soil and shrublands in cases of no drought. Chi-square test captured a significant association between land use type and drought level on dust emission (χ2 (6) = 47.33, р < 0.001). However, Cramer’s V value (0.13, р < 0.001) indicates that the association captured by the chi-square is weak, suggesting that other factors, perhaps meteorological variables, are at play in the spatial distribution of dust sources in this region. The proportion of dust points differs significantly during severe/exceptional droughts versus no drought or abnormally dry/moderate drought in both cultivated lands and grasslands. The proportion of dust points in bare lands and shrublands, however, did not significantly change between no drought and severe-exceptional drought. These results suggest anthropogenic land use in southwestern U.S. is significantly associated with drought in terms of dust emission. Human activity amplifies of the effects of drought by increasing soil erodibility; thus, adopting land management practices to resist wind erosion is crucial. Further investigations on a global scale should provide more information on this association.