Identifying and characterizing dust point sources in the southwestern United States using remote sensing and GIS

Abstract

Documenting geomorphology and land use/land cover associated with the aeolian dust sources is needed to build more robust models simulating wind erosion and dust emission. It is also important to set the base for future studies aiming to quantify the effect of anthropogenic land-use change on dust emission. In this research, dust point sources were detected in the Southern Great Plains and Chihuahuan Desert regions of the United States (U.S.) for 2001–2016, encompassing a period of extreme drought. Dust points were detected using overlay analysis of brightness temperature difference images of MODIS and MODIS true color images for the days where dust plumes were visible. This study aims to identify low emission surfaces as well as high emission surfaces in terms of geomorphology and land cover. A total of 1508 dust points were detected, where 1258 points are located in the Southern Great Plains, and 187 points are located in the Chihuahuan Desert. 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 the dominant land cover and aeolian sand sheet is the dominant geomorphic class. Ephemeral lakes (i.e., playas) produce the most dust sources per unit area. Cultivated croplands enclose 43% of the dust points, while shrublands and grasslands, combined, enclose 45% of the points. Results from this study confirms the importance of playas as a dynamic source of dust in southwestern U.S. Moreover, this study suggests that anthropogenic factors play a major role in dust emission within southwestern U.S, although bare lands in particular that are not subjected to anthropogenic factors (e.g., the White Sands dune field) are also emitting dust. Future research is needed to statistically analyze the contribution of different land-cover types on dust emission in the region.