Abstract:
Long-term trend of total column ozone at high altitude region in Ladakh is studied, using a total ozone mapping spectrometer and an ozone monitoring instrument during 1979–2008. In the region, total ozone exhibits seasonality with maximum in spring and minimum in autumn. The decreasing trend of total ozone was found as −2.51±0.45% per decade with 95% confidence level in the region. Ozone deficiency in the Ladakh region is strongest (−33.9 DU at Hanle) in May and weakest (−11.5 DU at Hanle) in January–February. In the study, the solar maximum in 1990 is in phase with ozone maximum, while ozone variation lags in phase with the 1980 and 2000 solar maxima. However, a significant correlation between total ozone and sunspot number is achieved in the westerly phase of quasi-biennial oscillation during spring season. Decreasing trend of ozone in the region is correlating well with the cooling rate in the lower stratosphere.
