The weather patterns responsible for atmospheric dust in the Great Plains
Abstract
While the North American Great Plains is not currently one of the world's most prominent dust sources, it has a rich history and possible future as an important dust source. Dust storms still occur in the plains, producing a variety of potential hazards to public health, transportation, and land degradation. Recently, several studies have investigated the relationship between the occurrence of dust in the Great Plains and factors such as precipitation, soil moisture, and vegetation. A complementary approach is to identify the specific weather patterns associated with dust occurrence. Doing so provides an alternative method by which one might forecast dust outbreaks, or understand the sources of observed dust variability.
In this study we make use of a previously published atmospheric classification (Evans, et al. 2017) that defined a set of weather states for the southern Great Plains to identify the specific weather patterns most responsible for dust in various parts of the central US. The classification defined 21 distinct weather states that included various stages of both warm and cold frontal passages, cold northerlies, anticyclones, and a variety of summertime patterns not associated with mid-latitude cyclones. We use the time series of weather state as a basis for compositing Suomi-VIIRS daily aerosol observations at 1o resolution, focusing on the aerosol retrievals classified as dust. By comparing states with warm fronts in different locations, we can see that warm fronts enhance both the intensity and frequency of atmospheric dust in the northern Great Plains, but that the strength of this effect is dependent on how far north the warm front has advanced. In contrast, cold fronts produce some limited atmospheric dust at their southern extents, but less dust through most of the Great Plains. The summertime patterns all feature deep convection, and show enhanced dust along the western edge of the plains, likely due to thunderstorms generated in the lee of the Rockies. Classification analysis also allows for the calculation of the fraction of observed dust due to the occurrence of each weather pattern in a given year.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.A34B..03E
- Keywords:
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- 0305 Aerosols and particles;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 3305 Climate change and variability;
- ATMOSPHERIC PROCESSES;
- 3322 Land/atmosphere interactions;
- ATMOSPHERIC PROCESSES;
- 1622 Earth system modeling;
- GLOBAL CHANGE