Trimmed L-Moments of the Pearson Type III Distribution for Flood Frequency Analysis

Trimmed L-moments (TL-moments) can reduce the undesirable effects of small sample events when estimating large return period events. This study proposes a new method to investigate the TL-moments method for the Pearson type III (P-III) distribution and derives new formulas for the TL-moments of the P-III distribution. The formulas for the TL-moments of the P-III distribution derived by Mat Jan and Shabri (Theor Appl Climatol 127(1–2):213–227, 2015 ) are also corrected. From the simulation results, the TL-moments method of the P-III distribution proposed in this paper is almost the same as the TL-moments method proposed by Mat Jan and Shabri (Theor Appl Climatol 127(1–2):213–227, 2015 ), and it can show good parameter estimation performance when the sample size is small and C_s>2.0C_v . The annual maximum streamflow data in northern Shaanxi, China is used as a case study. The results show that the TL-moments (2, 0) method is the most suitable method for the Zaoyuan and Liujiahe stations and the Huangling station is best fitted with the TL-moments (3, 0) method.