Evaporation from a thin layer of wet sand

Abstract

Natural evaporation from wet sand is experimentally estimated by differential weigh and subsequently it is modeled empirically. The experiment consists in weighing, before and after being exposed to open-air ambient conditions, a shallow tray containing a layer of wet sand. The difference in weigh is taken as the amount of water evaporated during the experiment. Evaporation from a tray containing water only is similarly estimated and corroborated with a graduated cylinder. The procedure was repeated 42 times during the autumn and early winter 2007-2008, at Ensenada, Mexico (31°52′N, 116°40′W). Several meteorological variables (air temperature, solar radiation, relative humidity and wind speed, among others) were recorded at the site simultaneously. The main results are (1) Evaporation from a thin layer of wet sand was modeled successfully using air temperature and solar radiation as predictors; and (2) this evaporation and evaporation from a thin layer of plain water varied similarly, but, in average, the latter was about 12% less than the former. Copyright 2008 by the American Geophysical Union.