Using fuzzy logic to discriminate convective and statiform precipitation in Doppler weather radar

Doppler weather radar has become one of the important means of detecting and monitoring method for meteorological department. Doppler weather radar is widely used in the analysis of convective weather detection, diagnostic research, quantitative precipitation estimation and now-forecast, etc. Most applications of rain field observations by radar required to be able to identify convective and stratiform precipitation. For example to choose the coefficients of the Z-R relationship used to convert reflectivity factor (Z) into rain rate (R) and then into cumulative rainfall for hydrological operation. This topic used fuzzy logic method to discriminate stratiform and convective precipitation in rain field. Based on the differences of radar reflectivity distribution morphology between stratiform and convective precipitation, selected four recognition parameters, which were maximum reflectivity factor, altitude of echo top, vertical reflectivity gradient and horizontal reflectivity gradient. Firstly, we calculated each recognition parameter, afterwards using membership function converted each identification parameter into judgment factor between 0 and 1, then weighted and calculated all the judgment factors, finally chose a suitable threshold for the above result to obtain the stratiform and convective precipitation in rain field. This paper gave several typical examples of different weather to analyze the recognition validity. The results showed that four recognition parameters that selected can effectively identify stratiform and convective precipitation in rain field, and this algorithm can be expanded by adding more recognition parameters to further enhance the identification accuracy.