长江大通站径流量的丰平枯水年划分探讨

Classification of High/Medium/Low Flow Year of the Yangtze River According to Runoff at Datong Station

河流和河口水文研究一般都采用年平均径流量划分丰平枯水年。根据长江口枯季盐水入侵研究对径流量划分的需要,探讨了以大通站的年平均、洪季平均、枯季平均、枯季月平均径流量划分丰平枯水年类型的差异。结果表明:洪季平均和年平均径流量划分的丰平枯水年类型吻合度达74%,但是枯季平均和年平均径流量划分的丰平枯水年类型吻合度仅38%,枯季各月平均与年平均径流量划分的丰平枯水年类型吻合度平均为33%。对于长江口的各种研究来说,采用多种径流量指标划分丰平枯水等级是很有必要的。

In hydrological studies of river and estuary,high/medium/low flow year is generally classified according to annual average runoff. In response to the need of runoff classification in dry season,especially during saltwater intrusion in the Yangtze River Estuary,we examined the differences in classification results of high/medium/low flow year according to annual average runoff,flood-season average runoff,dry-season average runoff,and monthly average runoff in dry season. The classification results according to flood-season average runoff and annual average runoff coincide to a degree reaching 74%,while the results according to dry-season average runoff and annual average runoff coincide with only 38%,and the mean coincidence degree between monthly average runoff in dry season and annual average is 33%. The results suggest that multiple runoff indicators are indispensible for the classification of high/medium/low flow year in various researches on the Yangtze River Estuary.