NOWCAST: PAPERS OF NOTE

In the polarizing scheme that gives an ordinary Doppler radar the ability to "see" precipitation patterns inside clouds, the differential reflectivity, Z^sub DR^, must be calibrated with special care, however; if its bias is as little as 0.2 dB, polarimetric rainfall estimates will be off by 18%. Overall there are tour sets of measurements, one in the transmission path and three in the receiving path, '!he recommended procedure can achieve errors within 0.1 dB, it caution and care is exercised such that all differences in coupling losses are accounted for, noises are correctlv estimated and accounted for, and some measurements are repeated or bracketed by a companion measurement. An extension of the methodology used in this study could also be valuable to investigate the serial properties of other weather systems, such as tropical cyclones, tornadoes, and polar lows.-PASCAL.