关键词: 长江河口, 月平均海面, 经验特征函数

Abstract: The most obvious feature of the short term sia-level variations in the Changjiang estuarine area is the seasonal cycle, which is dominated by the runoff of the Changjiang river and a variety of ocean processes as well as other factors. The monthly mean sea-level changing range is from 40 cm to 70 cm. The changing magnitudes are significant within the estuary and decrease seaward due to the expansion of the runoff and the actions of other factors; consequently, the fluctuations of sea-surface slope varies with different seasons. The highest gradient occurs during the summer and autumn, and the lowest gradient occurs in the winter. Spatial and temporal patterns of monthly mean sea-leve1 of the Changjiang estuarine area have been calibrated by eigenfunction models identifying several distinct factors which in- fluence on the monthly mean sea-level. The most significant factors arc the variations in she runoff, atmospheric pressure and temperature, which account for about 45%, 23%, and 26% of total amount of monthly mean sea-level changes respectively, and the other two factors are abnormal change of the river runoff and the set-up resulting from moonson.

Key words: Changjiang Estuary, Monthly mean Sea level, Eigenanalysis