V N Nijampurkar
Articles written in Journal of Earth System Science
Volume 88 Issue 1 March 1979 pp 29-40
The concentration of radioisotopes7Be,35S were measured in Bombay since 1956 and22Na,210Pb,32Si since 1963. In Khandala and other stations such measurements have been made at irregular periods since 1961. In addition several measurements especially that of32Si were made in 1970. Data available todate from Indian stations is summarised and critically analysed.
We conclude that appreciable amounts of35S,22Na and32Si, over and above their production by cosmic rays, were produced during the high yield Russian tests as evidenced by their fallout between 1962–66. Based on the bomb produced excess the half period for their removal from the stratosphere is deduced to be less than 1 year. The ‘excess’ contribution of32Si due to bombs is, however, small; about 1% of its inventory in the oceans.
The present study shows that for stations where orogeny is the principal mechanism of precipitation, the annual fallout is independent of the annual rainfall.
Volume 90 Issue 3 November 1981 pp 227-235
The surface ice taken from the snout of the Nehnar glacier (Kashmir) in western Himalaya has been dated using radioisotopes32Si and210Pb to be 500 years. Based on the age distribution of ice and the expected activity of32Si in the fallout, the average rate of glacier movement over a period of the last few centuries is estimated to be about 6 m/yr.
The data obtained on32Si and210Pb activities in the surface ice samples in the ablation zone support our previous observation about the existence of five zones of alternately high and low activity of210Pb, which probably is a consequence of complex dynamics of Nehnar glacier.
The vertical profile of210Pb activity in an ice core correlates directly with the total beta activity. This radioactive horizon at an altitude of 4140 m appears to be located at a depth of 10–12m, which is lower compared to the 2–3 m observed earlier at an altitude of 4150 m.
Volume 93 Issue 2 July 1984 pp 135-140
The ice samples obtained from Dakshin Gangotri, Antarctica show the presence of nuclear debris, attributed mainly to French nuclear explosions. Cosmogenic7Be occurs at levels of 30 dpm/L. The vertical profile of
Volume 94 Issue 2 July 1985 pp 83-89
Using environmental radioisotopes silicon-32 and lead-210, the radiometric ages of ice at the surface and at 5 m depth at the snout of the Changme-Khangpu (