Year-to-year variation of ozone hole over Schirmacher region of East Antarctica: A synopsis of four-year measurement

Abstract

During the 16^th, 21^st, 22^nd and 23^rd Indian Antarctic expedition conducted in 1997, 2002-03 and 2004 respectively, measurement of columnar ozone have been made using MICROTOPS II Sun-photometer from the Indian station Maitri (70º 45^'S, 11º 44^'E). It is found that the ozone hole depth fluctuated from year-to-year. The minimum columnar ozone observed over Maitri was 135 (±9.3) DU, 185 (±12) DU, 126 (±9.7) DU and 159.8 (±8.8) DU during spring 1997, 2002, 2003 and 2004, respectively. Ozone concentration below 220 DU (nominal ozone threshold value) during Antarctic spring (day 225–365) over Maitri has been observed to be 45.1 %, 20.7 %, 62.7 % and 60 % in 1997, 2002, 2003 and 2004, respectively. The chemical loss of ozone (total ozone values below 220 DU) over Maitri during 2003 (day 225–365) was found to increase by a factor of 0.4 when compared to 1997, and by a factor of 2 when compared to 2002. The observations at Maitri also showed an event of major stratospheric warming during 2002. The ozone hole in the year 2002 was not found to be deep and further recovered quite early when compared to 1997, 2003 and 2004.