Matador 2002 Field Test: A Pilot Experiment on Heat and Aerosol Transport by Dry Convection and Dust Devils

Recent research suggests that mineral dust play an important role in the earth's climate by altering the atmospheric radiation budget and 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 and moisture content, vegetation cover, topography, and weather. Dust devils are frequently observed over terrestrial deserts and are ubiquitous features of the Martian landscape. These small convective vortices play an important role in the vertical transport of mineral dust and heat, both on Mars and on earth. Charge separation within their ``dust clouds'' produce strong electric fields, which can ionize the thin Martian atmosphere and might have important implications for its chemistry. Moreover, terrestrial dust devils are a hazard to general aviation, while Martian dust devils are potentially harmful to spacecraft Landers. Our group has been conducting field projects to understand the electrification of dust devils and the contribution of dry convection and dust devils to the vertical transport heat and aerosol (mineral dust). Our initial results show that dust devils produce heat fluxes that are about two orders of magnitude larger than the background ambient flux. Indeed, it suggests that most of the vertical heat transport in active convective layers is done by coherent convective plumes. We will discuss our measurement techniques and summarize our most important results.