Dew condensation on different natural and artificial passive surfaces in a semiarid climate

Abstract

In this study, five passive radiative surfaces were analyzed for dew formation in south-eastern Spain; a dew condenser (RDC), a modified Class-A pan evaporimeter, the water stored in an open pond, the water stored in a covered pond, and the suspended shade cloth cover which covered the pond. In the case of the RDC and the pan, two different modeling approaches were used to estimate dew: (i) dew was correlated with meteorological variables and (ii) dew was derived from the mass transfer equation. In the other three cases, dew formation was assessed by analyzing the difference between the dew point and the water surface temperature.The RDC was more productive than the pan as the latter cooled less overnight and also underwent interspersed processes of evaporation and condensation. In the case of the RDC, both modeling approaches gave satisfactorily estimates whilst they were less accurate for the pan. On the water bodies, the water thermal inertia usually maintained the night water surface temperature above the dew point and strongly limited the dew formation. On the contrary, dew has been proven to exist on the cover, although the low amounts of dew deposited hinder its drainage to the water.