Detection and characterization of dust source areas in the Chihuahuan Desert, southwestern North America

Dust storms can disperse large quantities of fine aeolian sediment regionally and even globally. These extreme aerosol events frequently are characterized by multiple dust plumes developed simultaneously over a large region. In the Chihuahuan Desert of southwestern U.S. and northwestern Mexico, these dust outbreaks are seasonally transported long distances across North America. However, dust sources in this region are not well characterized. Remote sensing and meteorological data were used in this research to study the environmental and meteorological conditions that lead to extreme dust events for potential impacts on climate, visibility, and health-related air quality issues. I applied a technique that consists of examining visible spectral bands, as well as difference split window images for far-infrared observations at the wavelengths of 10, and 12 µm. I used a band math analysis of the IR channels with the previous wavelengths to analyze data from GOES-10, NOAA/AVHRR, and MODIS. This analysis enhanced the dust cloud in a way that the dust sources can be seen and identified easily on the images. This detection is based on brightness temperature differences between BT11-BT12. Also this study investigates the meteorological conditions that lead to mineral dust events in the Chihuahuan Desert region of the United States and Mexico by looking at NOAA HYSPLIT back trajectory analyses, weather maps, drought maps, and MM5 data. This methodology was applied to several dust events associated with long-distance aerosol transport to determine whether these surface features were persistent sources of dust in this region. Landsat and Land Cover images suggested that some of the areas identified as sources of dust were consistent with typical dust source types (e.g. bare soils, agricultural areas, and dry wetlands ). Results from NOAA HYSPLIT back trajectory analyses suggest wind speeds near 10 m/s occur during events, higher than observed during non-storm periods. Residence time calculations and source contribution function suggest similar large scale wind patterns from the southwest during dust events, consistent with dust transport as observed from satellite imagery. Weather maps showed a pattern of low pressure systems over the area of New Mexico (Albuquerque Low) suggesting that dust events are influenced by the formation of cyclones and fronts in the region. Drought maps showed, that for each of the study cases, that the area under study was experiencing different drought periods that helped dust production in the area. These findings establish a baseline for continued research in determining potential locations for future dust outbreaks in the southwestern U.S. and northwestern Mexico