Land use/land cover and point sources of the 15 December 2003 dust storm in southwestern North America

A major dust event occurred on 15 December 2003 in the Chihuahuan Desert region of Texas and New Mexico (USA) and Chihuahua (Mexico) and in the Southern High Plains region of Texas and New Mexico. Using a MODIS satellite image, 146 individual small-scale sources (plumes) of dust were identified. These plumes merged to form the regional-scale dust storm. The point sources were characterized with respect to land use and land cover using a combination of field work and aerial photography. Fifty-eight of the sources are on cropland, mostly on the Southern High Plains. Forty-nine are on rangeland, from across the entire region. Thirty of the dust plumes originate within playa basins, mostly in the Chihuahuan Desert.Point sources of dust only represent a small fraction of the total land surface at any given moment (i.e., the period when the image was acquired) because most of the land within the region was not subject to erosion during the event. In general, land use and soil characteristics of point sources matched those of adjacent areas that were not emitting dust at the time, suggesting that microscale variations in erodibility or meteorological factors may dictate the actual emission points of dust during individual events.