Cosmic ray produced Radioisotopes for studying the General Circulation in the atmosphere

The possibility of using cosmic ray produced radioisotopes for studying large  scale circulation in the atmosphere has been explored recently. The potential significance of these isotopes in the field of metrology arises because of the following features in their production and properties-(l) Several radioisotopes are available whose half-lives are comparable to time scales involved in the atmospheric circulation. Four of the isotopes (S35, Be7, P33, and P32) have half-life periods ranging from three months to a fortnight, and one (Na22) has a half-life of about two and a half years, and (2) Isotope production is continuous, constant, strongly dependent on the latitude and altitude in the atmosphere and independent of meteorological factors, These isotopes can be used for investigating the nature of circulation of air in the troposphere and the detailed mechanism of exchange of air between the stratosphere and the troposphere.   Experimental work on the use of these isotopes in meteorology has so far been confined mainly to determination of the concentration in rainwater by the Geophysics Research Group of the Tata Institute of Fundamental Research, Bombay. Some of the important results of these investigations are summarized in this pa per.