Energy balance microclimatic variations on a coastal beach

This report investigates the variation in energy balance microclimate that occurs across a coastal beach on a clear day. Four beach zones differing only in moisture conditions were selected for comparison. The completely dry sand with its high albedo and hot daytime surface temperatures had the lowest daily net radiation total. Over 90 % of this was transferred to the air by sensible heat flux. The saturated sand surface of the swash zone and the water surface of the surf zone had more of a marine climate. The great bulk of the high daily net radiation went into ground storage with most of the rest being used for evaporation. The wet sand zone represented the true transition zone of the beach and displayed a microclimate intermediate between the extremes of dry sand and ocean. Most of the net radiation went for evaporation, whose total was greater than that of the completely moist zones because of higher vapor pressure gradients. A marked difference in microclimate, caused by differing surface moisture-conditions is seen to exist in a very small horizontal distance under conditions of clear skies. Day and night patterns are reversed with differences between zones much more extreme under the influence of the daytime input of solar radiation.