According to data from 1956 to 1979, Northeast of China at an annual moisture level of 637.7 billion, the precipitation depth is 510.8 mm. While precipitation's distribution varies uneven, accounting for latitude, terrain as well as the differences between mainland and foreland. We can see features as follow: the regional precipitation is more in southeast areas, mountains, windward slope in particular than southwest areas or plains, and according to which, we can divided this region into humid zoon, sub humid zoon ,semi-arid zoon these three.
This means that the precipitation of these areas reach to 800 to 1200 mm. There are two parts formed this belt, one area starts in Biliu River in south, through Huntai River system and Toudaojiang areas until Changbai Mountain in northeast, centric Yalu River's downstream. Due to the abundant water vapor, windward slope, frequent typhoon activity, this near-sea area becomes the most wet place in Northeast of China, of which, Lishugou station of Yalu River have been an annual average of 1201.1 millimeters for many years. Another area more than 800 millimeters is the upstream of Lalin River and Hailang River, one of the tributaries of Mudan River. While, the range of 800 mms of rainfall is not very much and Daxigou station in Hailang River has an annual average of 1082 millimeters.
This means that the precipitation of these areas reach to 400 to 800 millimeters. The 400 isohyet, starts at the lower reaches of Eergu'Na River, along the west side of Daxinganling Mountains, to the southern tip of Haimulun River's up reaches, then eastward bends to Lubei, over wulanhaote and Qiaihaer, to Daqing in southeast and then to Dalai, Tongliao, and finally, the exit lies in the west part of Chifeng County, acts like the letter "S". Sub humid extensive areas seat in the east of the line. The region which has a rainfall between 400 mms to 800 mms takes up more than 80% of the total area, including the most of Heilongjiang Nenjiang basin, Second Songhua Basin, mainstream of Songhuajiang, Wusuli River, Tumen River, Yalu River, middle-low reaches of Liao River, Huntai Drainage and coasty rivers.
This means that the precipitation of these areas is less than 400 mms. There are few regions under such level, which includes Eergu'Na River, downstream of Nenjiang River, and upstream of Xiliao River. 300 mms rainfall isocline is the lowest level, closing on the west of Xar Moron River.
The information is provided from Disaster Risk Reduction Knowledge Service.
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