An operational rain stimulation experiment using warm technique over Rihand catchment in northeast India during summer monsoons of 1973 and 1974


  • R. Kapoor
  • K. Krishna
  • R. Chatterjee
  • A. Murty
  • S. Sharma
  • Bh. Murty


Weather Modification Operations


Experiments, using warm seeding technique, on operational basis, were conducted during 2 summer monsoons of 1973 and  1974, over the 13,000 sq. km catchment area of the Rihand  reservoir in the state of Uttar Pradesh, India. In the first year of  operation, seeding was not done on many seedable days when  flying could not be undertaken. Considering those not-seeded  days as control days and nearly equal areas adjoining the  eastern and western boundaries as control areas, the result was  evaluated by using 24 hours rainfall data from the ordinary  raingauges functioning in all the areas. In the second year of  operation, seeding was not done, in general, on every fifth  seedable day which was considered as control day. Seeded days, which were nearest to the control days, were considered as  experimental days for evaluation. The result was evaluated by  using 24 hours rainfall data from the ordinary raingauges and 5  hours rainfall data from the self-recording raingauges. The  analysis suggested an increase in rainfall in the catchment area  upward of 16 percent, which is statistically not significant.  Microphysical measurements were made concurrently with the  seeding operation. A summary of the measurements is presented.




Technical Notes and Correspondence