A Spatiotemporal Analysis of Annual Extreme Precipitation Based on a Regional L-Moments Precipitation Frequency Analysis Approach in Jiangxi Province, China

The frequency analysis of extreme precipitation is a tough challenge for all the governments in the world, especially for China, because of the short record length of the measured precipitation data series. Under this situation, Regional Frequency Analysis acted as a good method to improve the robustness and accuracy of quantile estimates.This study investigated precipitation frequency analysis through the application of the regional L-moments precipitation frequency analysis approach, based on annual maximum precipitation data series measured at 741 rain-gauge stations during 1950-2013 in Jiangxi province, China. The results indicated that: (1) the whole study area can be delineated into 17 Hydrometeorological homogenous regions based on hydrological and meteorological analysis; (2) Three Goodness-of-fit tests are applied to select the best fitted distribution among five commonly used three-parameter distributions. It is found that the GEV distribution performed best in most of the 17 regions. The GLO and GNO were identified as the best distribution in six homogenous regions; (3) The quantiles estimated through regional precipitation frequency analysis are much more robust and accurate than that from at-site frequency analysis. (4) the confidence interval obtained through regional precipitation analysis is much more narrow than that get from at-site analysis, which means that the quantile estimates are much more accurate and reliable.