Application of Radar to Measurement of Surface Precipitation
Final rept. no. 2, 1 Sep 1967-31 Aug 1968
MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF METEOROLOGY AND PHYSICAL OCEANOGRAPHY
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The report contains two major sections. In the first, consideration is given to the accuracy and practicality of measuring surface precipitation by radar. The second summarizes studies which have been made regarding mesoscale precipitation patterns and their relation to larger-scale circulations. It is concluded that for convective storms a properly instrumented 10-cm radar can provide more accurate measurements of rainfall over an area than can a network of gauges. A wave length as short as 3 cm is shown to be unsatisfactory for measuring precipitation because of attenuation. In widespread storms appreciable errors, occasionally a factor of two or three, may result from differences between the precipitation in the volume sampled by the radar and that reaching the surface. Observations of such effects are presented and discussed. Advantages and liabilities both of the radar and of a network of gauges for measuring precipitation over an area are illustrated by experiments in which simultaneous measurements by the two methods are compared. The second section of this report presents detailed descriptions of the structure and behavior of mesoscale precipitation areas and convective cells both in extratropical cyclones and in thunderstorm complexes. These descriptions will serve as a basis for physical and numerical studies of mesoscale phenomena.
- Active and Passive Radar Detection and Equipment