Spatial and temporal variations of precipitation concentration and their relationships with large-scale atmospheric circulations across Northeast China

Understanding the trends of precipitation concentration play a key role in watershed development and management. In this study, spatiotemporal and abrupt changes in the concentration index (CI) and their relationships with summer large-scale atmospheric circulations over Northeast China (NEC) were discovered. We used daily precipitation data from 71 meteorological stations and five large-scale atmosphere circulation indices for the period 1961–2016 across NEC. The results show that annual daily precipitation concentration in NEC decreased slightly in most areas. The spatial distribution of the CI ranges from 0.64 to 0.7 and the regions of the highest value were in Liaoning Province. The correlation between CI and different large-scale atmospheric indices show significant differences and mainly depend on the regional differences. Pacific Decadal Oscillation (PDO) and North Atlantic Oscillation (NAO) are negatively correlated with the CI in most regions of NEC, in contrast to the East Asian summer monsoon index (EASMI) and Multivariate ENSO Index (MEI). The Southern Oscillation Index (SOI) is negatively correlated with the CI in Liaoning Province and positivity correlated with the CI in Jilin and most of Heilongjiang Province. Compared to before 1975, a Eurasian continent anticyclonic circulation anomaly caused more clear days and higher solar radiation during 1976–2016.