Records of climatic changes and volcanic events in an ice core from Central Dronning Maud Land (East Antarctica) during the past century

The depth profiles of electrical conductance, delta(18)O, Pb-210 and cosmogenic radio isotopes Be-10 and Cl-36 have been measured in a 30 m ice core from east Antarctica near the Indian station, Dakshin Gangotri. Using Pb-210 and delta(18)O, the mean annual accumulation rates have been calculated to be 20 and 21 cm of ice equivalent per year during the past similar to 150 years. Using these acumulation rates, the volcanic event that occurred in 1815 AD, has been identified based on electrical conductance measurements. Based on delta(18)O measurements, the mean annual surface air temperatures (MASAT) data observed during the last 150 years indicates that the beginning of the 19th century was cooler by about 2degrees C than the recent past and the middle of 18th century. The fallout of cosmogenic radio isotope Be-10 compares reasonably well with those obtained on other stations (73degrees S to 90degrees S) from Antarctica and higher latitudes beyond 77degrees N. The fallout of Cl-36 calculated based on the present work agrees well with the mean global production rate estimated earlier by Lal and Peters (1967). The bomb pulse of Cl-36 observed in Greenland is not observed in the present studies - a result which is puzzling and needs to be studied on neighbouring ice cores from the same region.