Document Type
Thesis
Date of Award
2024
Degree Name
Master of Science (MS)
Department
Sustainability
First Advisor
Mark Sweeney
Abstract
We characterized spatiotemporal dust emissivity in the Northern Chihuahuan Desert (New Mexico, Texas, and Arizona, U.S.) using the Portable In-Situ Wind Erosion Lab (PI-SWERL) and measurements of soil crust strength, soil texture and soil moisture. Field-based measurements of emissivity were compared to the results of the Preferential Dust Source (PDS) scheme (Bullard et al., 2011) in the Chihuahuan Desert (Baddock et al., 2011) where 48% of satellite-observed plumes were sourced from ephemeral and dry lakes. Six landforms were tested: 1) ephemeral and 2) dry lake, 3) high and 4) low relief alluvial, and aeolian 5) sand sheet and 6) dunes. 434 four-season PI-SWERL tests measuring PM-10 (particulate matter <10 μm) and TSP (total suspended particulate) dust were grouped and analyzed by landform for comparison. PI-SWERL flux data reflect a large amount of inter-landform surface heterogeneity such that most landforms have overlapping emission potentials. Statistically, landform fluxes are the same except sand sheets produce larger fluxes (median of 0.38 mg/m2/s) than ephemeral (0.03 mg/m2/s) and dry lakes (0.04 mg/m2/s) (p ≤ 0.002). Ephemeral and dry lakes produce the largest maximum fluxes (13.7 and 6.1 mg/m2/s) but are highly seasonal, only emitting when soil moisture and crust strengths are low. Alluvial and aeolian landforms are limited from reaching this emission potential due to vegetation but will become dominant emitters if vegetation density decreases. The similarity in field-quantified landform emissions suggests that geomorphology alone cannot conclusively predict emissivity in this desert, but other factors such as seasonality and vegetation cover are important. The PDS model can be improved by integrating spatially and temporally heterogenous soil properties that are measurable in the field.
Subject Categories
Geology | Geomorphology
Keywords
Aeolian geomorphology, Chihuahuan Desert, dust emissions, PI-SWERL
Number of Pages
155
Publisher
University of South Dakota
Recommended Citation
L Harsha, Gwenn, "A FIELD-BASED STUDY OF DUST EMISSIVITY IN THE NORTHERN CHIHUAHUAN DESERT, U.S.: TESTING THE PREFERENTIAL DUST SOURCE SCHEME" (2024). Dissertations and Theses. 235.
https://red.library.usd.edu/diss-thesis/235