The Matador field project on convective plumes and dust devils
Abstract
Recent research suggests that mineral dust play an important role in the earth's climate, not only by altering the atmospheric radiation budget, but also by affecting cloud microphysics and optical properties. Moreover, dust can act as a catalyst for reactive gas species in the atmosphere and can influence photochemical processes. Many studies have shown that, on a micrometeorological scale, dust sourcing is sensitive to a large number of factors such as soil composition, soil moisture, vegetation cover, topography, and weather. Dusty convective plumes and dust devils are frequently observed over terrestrial deserts and are ubiquitous features of the Martian landscape. We show evidence that these convective systems play an important role in the vertical transport of mineral dust and heat, both on earth and on Mars. We also show that charge separation within terrestrial dust devils produce electric fields in excess of 50 kV/m. Electric fields produced by Martian dust devils probably ionize its thin atmosphere and might alter its chemistry. Thus, Martian dust devils are not only important sources of atmospheric dust, but are also potentially harmful to spacecraft Landers. Our group has been leading a field program to understand the electrification of dust devils and the contribution of convective plumes and dust devils to the vertical transport of heat and dust. Our results show that dust devils produce heat fluxes that are about two orders of magnitude larger than the background ambient flux. Indeed, they suggest that coherent convective plumes do a large fraction of the vertical heat transport in regions of intense convection. We discuss our theoretical framework, measurement techniques, and summarize our most important results.
- Publication:
-
EGS - AGU - EUG Joint Assembly
- Pub Date:
- April 2003
- Bibcode:
- 2003EAEJA.....3057R