Estimating net radiation using routine meteorological data at a tropical location in Nigeria

摘要

In this study, simple parameterizations, used to determine the net radiation, have been evaluated with dedicated field data from a tropical location at Ile-Ife, Nigeria. Separately determined were the net radiation for a clear-sky condition and a modification of this, incorporating the relative cloud amount as a multiplicative factor. Cloud amount has been computed as a ratio between the measured global radiation and that calculated for the clear-sky condition. In the absence of direct measurement of the global radiation, a simple empirical expression is given. From these estimations, differences between the clear-sky and the cloud-adjusted net radiation values were found to be substantial, thus indicating that cloudiness is an important factor influencing radiative balance of the tropical atmosphere. The scheme was compared with the actual measurements and remarkably good agreements have been obtained with correlations ranging between 0.87 and 0.94.