Solar and Net Radiation for Estimating Potential Evaporation from Three Vegetation Canopies

Abstract

Solar and net radiation data are frequent/y used in estimating potential evaporation (PE) from various vegetative surfaces needed for water balance and hydrologic modeling studies. Weather parameters such as air temperature, relative humidity, wind speed, solar radiation, and net radiation have been continuously monitored using automated sensors to estimate PE for three different vegetation canopies in the coastal plain of North Carolina. Mean daily solar radiation, among these three stations varied within about 70 percent only. Mean daily net radiation on pine forest canopy was at least 24% higher than on grass vegetation at the same latitude, indicating that use of net radiation from a forest site in Penman based methods may well overestimate the PE for a grass vegetation. Tests of self-calibration procedure by Allen (1997) and method of Hargreaves-Samani (1982) for estimating daily and monthly solar radiation at these coastal sites revealed that the former is more accurate and reliable than the later. The regression relationship developed using net and solar radiation for grass was different from the one reported in the literature for Bermuda grass in North Carolina.

Citation

Amatya, D.M.; Skaggs, R.W.; Cheschier, G.W.; Fernandez, G.P. 2000. Solar and Net Radiation for Estimating Potential Evaporation from Three Vegetation Canopies. Written for presentation at the 2000 ASAE Annual International Meeting, Paper No: 002135