Radar rainfall estimates in an alpine environment using different gage adjustment techniques

In order to mitigate the hostile effects of a complex orography on radar precipitation estimates, radar observations are here adjusted using a network of gages. Three techniques are analyzed and compared: 1) a simplified bulk adjustment technique based on a Z-R relationship with b=1.5; 2) a non linear Z(dB)-R-dB is derived by matching unconditional probabilities of rain rates measured by the gages to radar observed reflectivities above the gages (Probability Matching Method); 3) corrections of radar estimates (based on a single Z-R relationship) are derived through a Weighted Multiple Regression as a function of three independent variables. The three variables used in the regression are: A) the distance from the radar; B) the minimum height a meteorological target must reach to be visible from the radar site; C) the height of the ground above sea level. The analysis also focuses on the importance of quality controlling radar-gage data-pairs in order to use only good quality information from selected gages. (C) 2000 Elsevier Science Ltd. All rights reserved.