Land-Surface Processes, Dust Sources, and Particulate Fluxes of the 1930s Dust Bowl Drought in the U.S. Great Plains

Baylor University, Waco TX

Investigators

Abstract

This research project will evaluate whether agricultural practices were the dominant cause for wind erosion and continent-wide dust storms during the 1930s Dust Bowl drought as has been assumed for the past 80 years. The project will develop a new database for central North America to assess the spatial and temporal variability of natural and human-induced surface processes on wind erosion and dust emission estimates for the 1930s Dust Bowl drought. The project will yield new quantitative criteria to evaluate the role of cultivation, subsequent re-plowing, and the interactions among natural and human-related processes that led to reactivation of antecedent aeolian deposits and landscape denudation in the 1930s. This database will provide appropriate spatial-scaling for deriving estimates of dust emissivity from drought-stricken surfaces and the potential contributions of dust to regional and global atmospheric particulate loads. Many Earth system models underscore the vulnerability of the Great Plains in the 21st century to extreme droughts, with drying having the potential to exceed conditions in the 1930s, thereby increasing the potential for heightened aeolian activity. The enhanced understanding provided by this project of the spatial and temporal variability in dust generation during the 1930s drought will improve parameterization of atmosphere-land interaction models. Improvements in knowledge of these complex dynamics will provide insights regarding how to better mitigate against increases in atmospheric dust loads, which pose with increased risks of premature mortality and morbidity from respiratory, cardiovascular, and dust-borne viral diseases. To assess changes in vegetation, associated wind processes, and dust sources and fluxes the heart of the Dust Bowl on the Great Plains, the investigators will analyze aerial photography from 1936 and 1939. Targeted regions will include persistent drought areas in the Texas and the Oklahoma panhandles, adjacent surfaces in Kansas, Colorado, and New Mexico; and other potential dust sources areas in the western Nebraska sand hills and in western North Dakota. The investigators will conduct field-based studies at sites where analysis of images indicates that sand and other wind-blown particles accumulated in the 1930s, thereby providing insights into thickness, continuity and particle sizes of Dust Bowl deposits. A range of dust emission estimates will be derived from the distribution of classified land-surfaces and from empirical analyses of dust production and release for analogous surfaces in the western U.S. These dust release estimates will be evaluated with new field measurements of dust flux from soils with the use of the portable in situ wind erosion lab.