Team Blitz India
MUMBAI: A cloud-seeding experiment conducted in Maharashtra’s Solapur region has led to more than normal rainfall by 18 per cent, according to a research paper published recently in the Bulletin of the American Meteorological Society (BAMS).
Titled ‘CAIPEEX (Cloud Aerosol Interaction and Precipitation Enhancement Experiment) – Indian cloud seeding scientific experiment’, the experiment was carried out by scientists from the Indian Institute of Tropical Meteorology in Pune and other institutes, including Johns Hopkins University of Baltimore, USA.
The study involved hygroscopic cloud seeding, which is done in warm convective clouds with base height above freezing level. Hygroscopic seeding material, dispersed from burning flares, activates as large droplets and then grows by diffusion.
“Updrafts then loft the growing drops to the region of sub-zero temperatures (when the cloud top goes above the freezing level), where they can freeze heterogeneously and grow more rapidly through riming and aggregation, more efficient processes than warm rain formation. In addition, the ice splintering through the Hallet Mossop process contributes to the growth of aggregates,” the research noted. The hygroscopic cloud seeding triggered rainfall in convective clouds.
The study also evaluated glaciogenic seeding in cold clouds but found no significant impact on rainfall at the seeding location. However, an increase in rainfall was observed in the downwind area of the seeded region.
Scientists recommend the use of hygroscopic cloud seeding to enhance rainfall in water-scarce regions. According to the research paper, the experiment has key importance in the arid region, like Solapur city, where the demand for water supply is 224 MLD (million litre per day), but the average water supply in the city is only 168 MLD.
The experiment was part of a project initiated by the Ministry of Earth Sciences and highlights the potential of cloud seeding as a method to alleviate water stress in arid and semi-arid regions.
