Interannual Variation of Summer Rainfall at the Tianchi Station in the Changbai Mountains and its Associated Circulation Anomalies

The Changbai Mountains are located in the southeastern part of Jilin Province. Rainfall has a crucial effect on the forest ecosystem and water resource in the Changbai Mountains, which is a national key ecological function area. Based on the monthly precipitation data from 47 stations in Jilin Province and the ERA-Interim monthly reanalysis data from 1979 to 2016, we investigated the climate characteristics of summer precipitation at the Tianchi station in the Changbai Mountains and circulation anomalies associated with the interannual variation of rainfall at this station and compared the Tianchi station with the other stations in Jilin Province. Results show that summer precipitation at the Tianchi station and its interannual variation are approximately two times larger than that at other stations in Jilin Province. On one hand, the circulation anomalies associated with the interannual variation of precipitation at the Tianchi station are consistent with those for the entire Jilin Province. The circulation anomalies that favor more rainfall at the Tianchi station and the entire Jilin Province are characterized by a cyclonic anomaly over Northeast Asia and an enhanced East Asian jet stream in June and an enhanced western Pacific subtropical high and a northward-displaced East Asian jet stream in July and August. On the other hand, precipitation at the Tianchi station is associated with unique circulation anomalies, which are quite different or nearly opposite to precipitation in the entire Jilin Province, and can be attributed to the terrain of the Changbai Mountains. The results indicate that climate variability in the mountains can be related to the complicated and varying patterns of large-scale atmospheric circulation anomalies.