Operational Radar Measurements of Rainfall: The Accuracy of Point Estimates of Rainfall Rate
Radar-estimated and gauge-measured point rainfall rates are correlated. Regression lines are strongly influenced by the relatively few extreme points at high rainfall rates.
Radar measurements lead to the systematic range dependent underestimation of the point rainfall rates: ratios between the mean radar and mean gauge estimates vary from 1.0 at close ranges to 0.2 at long ranges.
Radar estimates exhibit large scattering: percentage of occurrences that the radar estimates lie between 3 and 1/3 times the regression value is approximately 70%.
The main cause for the underestimation and scattering are physical in origin: the inability to perform radar measurements close to the ground due to the orography and radar beam geometry, and the high spatial and temporal variations of precipitation.
KeywordsRainfall Rate Radar Measurement Radar Reflectivity Weather Radar Large Scattering
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- (1).Brownscombe, J.L. and B.D. Hems, 1989: Comparison of radar precipitation measurements with a dense network of daily raingauges — applications to radar networking. Weather radar networking, Seminar on COST project 73, 426–433. Commission of the European Communities, Brussels.Google Scholar
- (3).Joss, J. and G. Galli, 1981: Digital radar informations in the Swiss Meteorological Institute. Preprints 20th Conference on radar meteorology. Am. Met. Soc., Boston.Google Scholar
- (4).Joss, J. and A. Waldvogel, 1990: Precipitation measurement and hydrology. Radar in meteorology, 577–618. Am. Met. Soc., Boston.Google Scholar