The ozone hole measurements at the Indian station Maitri in Antarctica

Abstract

Stratospheric ozone is a trace gas of great importance as it filters harmful ultraviolet radiations reaching the earth surface. Since ozone influences temperature and dynamics of the stratosphere, it is also a climate-relevant gas by modifyimg the tropospheric temperature. Significant changes in the stratospheric ozone are, therefore, a concern for human health and climate. India has a dedicated polar research programme with two stations in Antarctica; Maitri (70.4° S, 11.4° E, since 1989) and Bharati (69.2° S, 76.2° E, since 2012). Semi-regular measurements of total column ozone (TCO) are carried out to monitor the changes in the ozone layer there. Here, we use the available TCO measurements from Maitri in the winters of 1999–2003 and 2006, to estimate the chemical ozone depletion for the first time there. We estimate the largest ozone loss (59% or 180 DU) in 2006, and smallest in 2002 and 1999 (44% or 160 DU) among the winters; consistent with the meteorology, as the winter 2006 was the coldest and 2002 was the warmest with the first-ever major sudden stratospheric warming over Antarctica. The Maitri ozone loss analysis is found to be representative for the whole Antarctica as assessed from the comparisons with the average TCO from all Antarctic stations and satellite overpass TCO observations. The study, henceforth, demonstrates the value and significance of continuous monitoring of the ozone hole at Maitri to assist the policy decisions such as the Montreal Protocol and its amendments and adjustments.