Analysis of precipitation changes and its possible reasons in Songhua River Basin of China

Changes in precipitation have a great influence on human beings. The study of precipitation can aid in understanding regional climate change characteristics and the hydrological cycle. Therefore, in this study, the standardized precipitation index is combined with a simple linear regression test, Mann–Kendall trend analysis, Sen's slope method, principal component analysis and partial correlation analysis to study precipitation and drought distributions in the Songhua River Basin and the causes of precipitation changes in this area. The results are as follows: (1) The average annual precipitation change in this area is not significant, but there are significant differences in seasonal precipitation changes. (2) On a long-term time scale, this area presents a wet trend from southeast to northwest. On a short-term time scale, spring and winter show a wet trend. Winter has changed significantly. Summer and autumn show a dry trend. (3) The average annual and rainy season (RS) precipitation shows step change characteristics. Precipitation change in RS is the main reason for annual precipitation change. (4) The Asian meridional circulation/zonal index have significant effects on precipitation and dry/wet changes in this area. The western Pacific subtropical high and the East Asian summer monsoon are also important factors in this area.