Geomorphic and land cover characteristics of aeolian dust sources in West Texas and eastern New Mexico, USA

Wind erosion in West Texas and eastern New Mexico typically happens in localized source areas while most of the landscape is not eroding. Dust source areas were located and characterized according to type of geomorphological surface and land cover. For 2001–09, 27 erosion event days were identified where dust plumes were visible on MODIS satellite images. From these images, 625 point sources were located. Geomorphology and land use (land cover) were mapped and overlaid on the dust source point map. In terms of geomorphology, 79% of sources occurred on sand sheets, which comprise 50% of the region. Other geomorphic surfaces were sand dunes (5% sources from 12% area), loess (4%/24%), playa (3%/1%), high relief alluvial (3%/6%) and low relief alluvial (6%/5%). Sand sheets (here, anthropogenically disturbed) produce more sources than other geomorphic categories, with playas producing the most sources per unit area. Results for land use and land cover reflected cultivated cropland (57%/33%), shrubland (17%/32%), grassland (20%/31%) and urban (4%/4%). Cropped land produces proportionately more dust than rangeland or other land uses. With dust emission dominated by relatively uniform geomorphology, the data highlight the strong anthropogenic influence on the spatial pattern of observed dust sources in the region.