On the Problems of Rainfall Measurements by Radar

[摘要] The Rayleigh approximation of small particles for microwave region cannot be satisfied to all raindrops. The approximated value of radar reflectivity factor Z (when πD/λ«1) was compared with the theoretical value (calculated from the Lowan's table and dropsize distributions). The attenuation constants for various kinds of rain are also listed from the same table.The antenna effective area for meteorological target is somewhat less than the effective area for point target. The effective antenna receiving area for the usual meteorological radar is about 0.4 times the actual aperture.Areal rainfall measured by radar rainfall contours is compared to raingauge observations, about 23 gauges in a section of 638 km2. The accuracy of the radar rainfall thus obtained is about ±5.7% when integrated for a period of more than an hour and it corresponds to the raingauge network of about one gauge per 80km2.

[学科分类] 大气科学