Sources of origin and meteorological importance of hygroscopic and iceforming nuclei

The hygroscopic nuclei whose source region during the monsoon is the sea penetrate far into the interior and play important role in development of precipitation well inland. The fraction of such nuclei present in the total aerosol constitutes a more dependable criterion for distinguishing maritime airmasses from those of others. Development of rain frequently by all-water and ice-crystal mechanisms have been suggested by the large concentrations noticed of the hygroscopic and ice-forming aerosols respectively. While it is seen that there is a major identifiable singular source, which is the sea, for hygroscopic aerosols at Delhi, it does not appear to be so in the case of ice-forming nuclei. The latter are of varied origin and might be maritime, continental, stratospheric etc

Cloud seeding experiment using common salt

An experiment on artificial stimulation of rain using a warm cloud seeding technique was undertaken in three nearby climatologically similar regions, Delhi, Agra and Jaipur in northwest India. Analysis of the data from 18 experiment-seasons has suggested a positive trend of the result, which is found significant by statistical tests

The ozonesonde intercomparison experiment at Thumba

An Indo-Soviet collaborative experiment on Ozonesonde Intercomparison was conducted at TERLS in March 1983. Thirteen rocket ozonesondes, eleven balloon ozonesondes and seven meteorological rockets were launched from Thumba. The rocket and balloon soundings were supported by on site Dobson spectrophotometric observations, surface ozone measurements as well as measurements with a Volz type filter photometer. The programme has yielded data on ozone vertical profiles from eleven rocketsondes, seven balloon-sondes and four sets of Umkehr observations. The data is studied with a view to intercompare the various sensors