Validation of Satellite Ultraviolet Radiation data with Ground Based data in the Eastern site of Nepal

The main objective of this study is to validate the satellite estimated ultraviolet (UV) data with ground based data in Biratnagar (26.45° N, 87.27° E) which falls in the eastern part of Nepal and is located at an elevation of 72m from the sea level. The ground based (GB) measurements and the satellite estimation were performed by NILU-UV irradiance meter and EOS Aura OMI satellite respectively. The NILU-UV irradiance meter is a six channel radiometer designed to measure hemispherical irradiances on a flat surface. Meanwhile the Ozone Monitoring Instrument (OMI) on board, the NASA EOS Aura space craft is a nadir viewing spectrometer that measures solar reflected and back scattered light in ultraviolet and visible spectrum. The study was performed for the year 2011. Considering the data obtained from OMI and GB the relative differences between predicted OMI and ground based UVI assuming normal distribution ±1σ was found to 1.6±13.65 in May and 0.19±4.73 in November. Further study showed that the ratio of predicted OMI UVI to that determined from ground based measurement is about 1.0. The UVI ratio in summer season was also found to 1.0.