Cloud-seeding is the process of spraying hygroscopic nuclei and common salt on warm clouds and silver iodide on cold clouds from aircraft. It results in 40 per cent additional rains.
The official weather forecasting agency, India Meteorological Department (IMD), in its first advance forecast had predicted 100 per cent normal rains over the country in general, but IMD director-general SK Srivastava had admitted. there may be pockets of deficient rainfall areas, particularly in south India.
The Centre for Mathematical Modelling and Computer Simulations (C-MMACS) while predicting normal rains for the country in June said that rainfall would be deficient in southern states, lying south of 20 degree N latitude.
The Visakhapatnam-based Centre for Environmental Studies (CES) recently conducted a study showing that artificial rainfall through cloud-seeding operations during the monsoon season over the predicted rainfall deficient areas could generate 30 to 40 per cent additional precipitation at cheap cost. The cost of producing 1,000 litres of precipitation amounts to one paisa only. The study also cited the Indian Institute of Tropical Meteorology (IITM) cloud-seeding operations in 1973-86 at such cheap cost.
Dr Tipirneni Shivaji Rao, CES director, expressed concern over the forecast of deficient rainfall over some areas in south India. He has said that some pockets have been receiving deficient rainfall for the past consecutive three years and the rainfall in the last north-east monsoon was also deficient.
If again in the coming south-west monsoon these areas get deficient rainfall, it would be a rude shock.
Dr Rao, in this context, has written to President APJ Abdul Kalam to urge the concerned states to call for tenders on cloud-seeding operations by following the example of the Maharashtra which has already issued tender documents in this connection. He said last year Karnataka spent Rs 8 crore on cloud-seeding operations with two radar stations located at Bangalore and Gadag and the operations were successful.
Dr Rao also said that Australia, China, Indonesia and other south-east Asian countries have begun cloud-seeding operations this year.
The scientists at Atmosphere Study Centre in the Indian Institute of Technology (IIT), Delhi, when contacted, said cloud-seeding operations is a viable option for mitigating rainfall deficiency, but refused to be named in person.