Variation of total columnar ozone characteristics over Dibrugarh, India and comparison with satellite observations over the Indian subcontinent

In this study, we investigate the characteristics of the total columnar ozone (TCO) over Dibrugarh (27.3° N and 94.6° E), India for the period September 2007 to February 2009 using Microtops II Ozonometer. These measurements are compared with TCO data available from Total Ozone Mapping Spectrometer (TOMS) on board Nimbus-7 satellite for the same period. It has been observed that the TCO increases from morning till noon and then decreases rapidly in the afternoon. A distinct seasonal variation of TCO is observed with low value in the months of September–December and high values in the month of April, May and June as seen from both Microtops II and TOMS measurements. Satellite observations reveal that the TCO at all latitudes is nearly equal in the months of September–November and May to August. The seasonal variation of TCO between December to May is nearly a mirror image between low and mid latitudes along the three longitudes sectors.