Radar echoes from monsoon rain

Abstract

The use of radar has placed in the hands of the meteorologist an entirely novel and new technique for physical meteorological re-search and local short-term weather fore-casting. A centimetre radar can permit. the measurement of rainfall almost as accurately as isohyetal patterns derived from micro-network of raingauges (1948*). In addition, it can give a pictorial representation of the growth and movement of precipitation cells, progressively with time. During and after the World War II a number of observations have been made in different countries for locating rainstorms, thunderstorms, cold fronts etc with the help of micro-wave radars having their operating wave-length in the region of S (10 cm), X (3 cm) and K (1 cm) bands. As radars were not available commercially it was not possible to utilise them for meteoro-logical purposes more extensively during the war. Even today the cost of the equipment. is prohibitively high and observations are being taken, wherever possible, with the help of radars released from war surpluses. The present paper describes the results of observations made with a 3-cm radar (AN/ APQ-13) obtained from war surpluses. This radar has peak power of 40 kilowatts, beam width of 3° and frequency of 9375 megacycles (3.2 cm). The equipment was received in a very poor -condition and con-siderable time had to be spent to put it in commission. As the radar was essentially meant for installing in aircraft it was suitably modified to he used as a static ground instal-lation.