Effect of spatial and temporal “drought legacy” on dust sources in adjacent ecoregions

Authors: EIBEDINGIL, IYASU - University Of Texas - El Paso; GILL, THOMAS - University Of Texas - El Paso; KANDAKJI, TAREK - Texas Tech University; LEE, JEFF - Texas Tech University; LI, JUNRAN - University Of Tulsa; Van Pelt, Robert - Scott

Submitted to: Land Degradation and Development
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/12/2023
Publication Date: N/A
Citation: N/A

Interpretive Summary: The southwestern United States is a major dust source region in the United States. Agricultural areas in the Southern High Plains of Texas and the Chihuahuan Desert areas of western Texas, southern New Mexico, and southeastern Arizona have different land uses, but both emit dust during wind events in the winter and spring of the year. With the changing climate, droughts are expected to become more frequent and severe in the future.Scientists at USDA-ARS, the University of Texas at El Paso, the University of Tulsa, and Texas Tech university examined dust storm data from remote sensing and drought records from regional weather stations to examine the linkage between antecedent drought and the frequency of dust events. It was found that the dust sources in the Chihuahuan Desert responded to droughts in the severe to exceptional category in the one to three years before the dust events, probably due to the mortality of native vegetation and reduction in protective ground cover. In the Southern High Plains, the droughts did not have to be as severe and dust emissions increased when the present year or year immediately before had been classified as abnormally dry to moderate drought, probably due to the failure of dryland crops and resulting bare soil surfaces in the cropped fields. This has implications for forecasting dust events that negatively affect human health.

Technical Abstract: The Southern Great Plains and Chihuahuan Desert regions are some of the most dust-event prone areas of the United States. Dust events in these regions are assumed to be magnified by drought. This study relates the temporal and spatial “drought memory” on the generation of dust events from 2001 to 2014. Results indicate that dust points in the Chihuahuan Desert were highly concentrated in areas of severe to extreme drought, while those in the Southern Great Plains span a wider range of drought conditions. There were an increased number of dust events in those regions which were experiencing or recovering from severe to exceptional drought conditions, especially in the southwestern Southern High Plains, west and south of Lubbock, which is a region dominated by non-irrigated (rainfed) cropland. At lower temporal averaging domains (one week and 1-year), drought showed a strong connection with the dust event initiation points in the Chihuahuan Desert at severe to exceptional drought conditions. This was irrespective of different spatial scenarios, however, dust points in the Southern Great Plains were linked to lower drought intensities of no drought to abnormally dry. Drought, especially when extending over multiple years, indeed appears to play some role in driving dust events in the Southwestern United States, though it appears to be more locally-focused and likely magnified by the more intensive land use in the Southern Great Plains region than in the Chihuahuan Desert.