On some aspects of tropospheric ozone variability over the Indo-Gangetic (IG) basin, India

Abstract

To study tropospheric ozone variability over the Indo-Gangetic (IG) basin, monthly tropospheric ozone residual (TOR) data has been analysed for the 1979–2004 period. Tropospheric column ozone has been observed to have a maximum during late summer (48 ± 4.1 DU) and a minimum during late winter (30 ± 4.2 DU) over the IG basin. The amplitude of the seasonal cycle has been observed to be comparatively larger over the western part of the IG region (∼51 ± 2.3 DU) than over the central (∼47 ± 3.2 DU) and eastern parts (∼47 ± 3.2 DU) of the region. Similarly, the seasonal variation in tropospheric ozone has been observed to be comparatively larger over the western part of the IG region (∼22 DU) than over the central (∼18 DU) and eastern parts (∼17 DU) of the region. The difference in tropospheric ozone amount over the eastern and western parts of the IG region also shows seasonal variation with a large difference (up to 4 DU) during the monsoon season. The monsoon system plays an important role in the seasonal variation of the tropospheric ozone over the different parts of the IG region.