Cloud Aerosol Interaction and
Precipitation Enhancement Experiment

Program Structure

CAIPEEX has two components viz. (1) Cloud-Aerosol interaction and (2) Precipitation Enhancement. Understanding of cloud-aerosol interaction is pre requisite for the second component. Aircraft observational programme has been proposed for the first component.

The proposed experiment is planned to carry out in three phases. Phase I is devoted for intensive cloud and aerosol observations over different parts India during the period May- September 2009. In Phase II, precipitation enhancement experiment would be carried out by artificially seeding the clouds in the years 2010 and 2011. The analysis of the data will be carried out in phase III in the year 2011-12.


Phase I: Background Aerosol and Cloud Microphysical Observation

  • To measure background concentrations of aerosols and CCN during monsoon season.
  • Observations of hydrometeors in the clouds.
  • Observations of space-time variability ( during monsoon season) of trace gases over India
  • Measurements of Radiation parameters.
  • Selection of site for the second phase experiments.

Phase II: Cloud Seeding Experiment

Based on the results of Phase I experiment, a randomized experiment will be carried out in the monsoon and post monsoon seasons of years 2010 and 2011. The experiment will use statistical methods in conjunction with numerical model simulations to evaluate the performance of the experiment. Two aircraft will be used for cloud microphysics observations and cloud seeding purposes. Hygroscopic flares will be used for triggering the coalescence process in the cloud. A dense network of automatic rain gauges will be installed in the experimental area to measure the rainfall. Rain water samples will be collected from the seeded clouds and non seeded clouds. The chemical analysis of rain water samples will be carried out to understand effect of seeding on the precipitated water.

Phase III

Analysis of data and preparation of report will be done in the year 2011-12.

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