Delineation of Air Temperature Based Models for Estimation of Global Solar Radiation

Data on global solar radiation is an essential input variable to many crop models from the process oriented crop models at field scale, to the land surface based ecological models at regional scale and the global circulation models. Here an attempt has been made to delineate four temperature based relations proposed by Hargreavesand Samani (1982), Bristow and Campbell (1984), Richardson (1985) and Goodin et.al. (1999) for their relevance to the actually measured. Data on measured solar radiation, minimum and maximum air temperatures collected from ICRISAT, Hyderabad for the period 1st Jan 2009 to 1st April 2011 was used in the analysis. Models performance has been evaluated using mean bias error, root mean square error, mean absolute percentage error and D-index of agreement. The comparative analysis revealed that among the four models Bristow-Campbell (1984) model estimated solar radiation comparatively with less errors and the estimated radiation values were most close to the measured values.