WEATHER RADAR STUDIES.
Final rept. 1 Jan 67-30 Jun 68,
MCGILL UNIV MONTREAL (QUEBEC) STORMY WEATHER GROUP
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It appears from one large snowstorm that radar can be used to measure snowfall rates and amounts over areas up to 10 000 sq mi, perhaps 30 000 sq mi. For dry snow a wavelength of 3.2 cm can be used, but few situations yield reliably dry snow at all heights. In a large thunderstorm, proportionality was found between the mass of rain in the storm and the rate at which the rain was falling out. The rate of generation of rain rose almost exponentially, then changed to decay almost exponentially, and the observations were fitted closely by the relation P sub g K C P, where P sub g is rate of generation of precipitation and C and P are masses of cloud and precipitation. Statistics of attenuation by rain on microwave links, either ground-to-ground or ground-to-satellite have been calculated from weather-radar data. It has been found, for example, that at 10 GHz, an attenuation of 30 db is exceeded at low angles for about 15 minutes per year, most likely on a single occasion, while 10 db is exceeded for five times as long, distributed over several occasions. Author