Mumbai, July 2: Former president APJ Abdul Kalam on Monday said hilly areas prone to cloudbursts need polarimetric radars to forecast warnings about impending disasters .
Such radars can give a fairly accurate estimate of the amount of rainfall expected he said .
The Meteorological department in India has such radars in Delhi, Mumbai and Nagpur, and ten other places. The radars will help in correctly gauging the quantity of water in clouds the size of water drops, whether rainfall will be heavy or normal and other inputs, Dr Kalam said.
What are polarimetric radars?
Most weather radars transmit radio wave pulses that have a horizontal orientation. Polarimetric radars (also referred to as dual-polarization radars), transmit radio wave pulses that have both horizontal and vertical orientations.
The horizontal pulses essentially give a measure of the horizontal dimension of cloud (cloud water and cloud ice) and precipitation (snow, ice pellets, hail, and rain) particles while the vertical pulses essentially give a measure of the vertical dimension.
Since the power returned to the radar is a complicated function of each particles size, shape, and ice density, this additional information results in improved estimates of rain and snow rates, better detection of large hail location in summer storms, and improved identification of rain/snow transition regions in winter storms.
