An experimental determination of the radiative properties and climatic consequences of atmospheric dust under nonduststorm conditions

Abstract

A comprehensive experiment was conducted at Phoenix, Arizona, involving the monitoring of global solar radiation and 8–14μm and 10.5–12.5μm thermal radiation, as well as surface air temperature, vapor pressure, and dust concentration. Analyses of the data, which were all obtained under normal weather conditions, revealed that as dust concentration increases, the transmittance of the atmosphere for solar radiation decreases but the effective emittance of the atmosphere for thermal radiation increases. These analyses also demonstrated that the vertical redistribution of dust with season greatly alters the flux of thermal radiation to the surface, but has no effect upon the total solar flux to that level. These relationships were all numerically quantified and used to investigate the climatological consequences for the earth as a whole. It was demonstrated that the most probable effect of an increase in the atmospheric dust content would be a warming of near-surface air temperatures, due to a net increase in the radiant energy input to the surface.