Estimation of monthly average daily solar radiation from measured meteorological data in Yangtze River Basin in China

Geological Survey program of China Geological Survey 1212010611402；Special Fund for Land and Resources Research in the Public Interest 201111023Solar radiation is the principal and fundamental energy for many physical, chemical and biological processes. However, it is measured at a very limited number of meteorological stations in the world. Estimation of solar radiation from measured meteorological variables offers an important alternative in absence of measured solar radiation. In this work, 20 developed models using measured meteorological variables are explored to estimate monthly average daily solar radiation at 13 stations in Yangtze River Basin in China. Two scenarios are considered. When sunshine duration is available, monthly average daily atmospheric water vapor pressure, relative humidity and precipitation do not contribute to the improvement in estimation accuracy of the sunshine-based models. It is therefore unnecessary to take them into account, and the newly developed model 6 is proposed and can provide a good method for the estimation of monthly average daily solar radiation in the study area. If sunshine duration is not available, inclusion of monthly average daily atmospheric water vapor pressure, relative humidity and multiplication maximum by minimum ambient temperatures can significantly improve the estimation accuracy of the temperature-based models. While monthly average daily precipitation does not contribute to the improvement in estimation accuracy. And model 20 is proposed and it is more applicable in area with larger ambient temperature range