Inter-Annual and Seasonal Variability in Ambient Ultraviolet-B Radiation Level at a Tropical Region of Indo-Gangetic Plain

This study evaluated the annual, seasonal, and diurnal variations in the ambient UV-B levels at a tropical region of the Indo-Gangetic plain during 2016 – 2018. Prominent seasonal variations in ambient Ultraviolet-B (UV-B) levels were recorded. Daytime cumulative UV-B varied from 16.75-37.45 (2016), 13.08- 35.89 (2017) and 14.76-34.5 (2018) during summer; from 24.02-3.65 (2016), 18.32-3.11 (2017) and 11.09-2.09 (2018) during winter and 25.56 – 41.17 (2016), 20.1 – 39.21 (2017) and 14.82 – 37.18 (2018) during rainy season. The ambient UV-B level was dependent on numerous meteorological variables (cloud cover, relative humidity, rainfall, and sunshine hours), astronomical factors (Solar Zenith Angle), and pollutants (like tropospheric ozone, sulphur dioxide, nitrogen dioxide, and aerosols). Monthly average UV-B levels positively varied with sunshine hours and PAR and inversely varied with cloud cover. This study suggests that the region is exposed to highly dynamic UV-B levels, which could be a potent threat to plants specially grown during summer-rainy seasons. The study could be further expanded for the entire region using various mathematical tools.