Comparison on Relationship between Western Pacific Subtropical High and Summer Precipitation over Dongting Lake Basin Based on Different Datasets

摘要

The Western Pacific Subtropical High (WPSH) is a principal component of the East Asian summer monsoon system. This study was to compare the relationship between the WPSH and summer precipitation in Dongting Lake basin (24 degrees 35 '-30 degrees 27 ' N, 107 degrees 13 '-114 degrees 18 ' E) based on different datasets by employing the multivariate regression analysis. The observed precipitation data was from China Meteorological Data (CMD) sharing service system and the six gridded precipitation datasets were CFSR, ERA-Interim, CMAP, GPCP, CRU, and PREC/L, respectively. The WPSH exerted different influences on the precipitation of summer months. The indexes including westward extension ridge point index and northern boundary index in June, ridge line index and northern boundary index in July and August had important effect on the precipitation over Dongting Lake Basin. The gridded data could generally reproduce the relationship between the ridge line index and precipitation in July. The relationship between the northern boundary and the precipitation from gridded data was similar to that from observed data in June and July, while the relationship between the western extension ridge index and the precipitation in June could be reproduced by the gridded data except CFSR and ERA-Interim. Only in part area, the relationship between the intensity index and the CMD precipitation could be reproduced by gridded precipitation. The fitness of correlation in some area from the CMD could be reproduced by the gridded data. General speaking, GPCP precipitation data was more applicable to the Dongting Lake Basin in studying on the relationship between the precipitation and a single index of WPSH.