A graded index for evaluating precipitation heterogeneity in China

Precipitation heterogeneity has a nontrivial influence on human life. Many studies have analyzed precipitation heterogeneity but none have proposed a systematic graded index for its evaluation, and therefore, its true characteristics have not been expressed. After comparisons of various methods, the precipitation concentration degree (PCD) method was selected to study precipitation heterogeneity. In addition to the PCD, normal distribution functions, cumulative frequencies, and percentiles were used to establish a graded index for evaluating precipitation heterogeneity. A comprehensive evaluation of precipitation heterogeneity was performed, and its spatiotemporal variation in China from 1960 to 2013 was analyzed. The results indicated that (1) seven categories of precipitation heterogeneity were identified (high centralization, moderate centralization, mild centralization, normal, mild dispersion, moderate dispersion, and high dispersion) and (2) during the study period, the precipitation in more parts of China tended to be normal or dispersed, which is beneficial to human activities.