STUDIES ON DYNAMICS OF SOME RIVER DELTAS AND LAKES USING LANDSAT-MSS IMAGERY

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  • Institute of Geography, Academia Sinica

Online published: 1979-01-15

Abstract

In order to grasp their dynamics, it is necessary to have some means to monitor their changes between short intervals. Remote sensing technique is an ideal one among these means- This article is an attempt to study the dynamics of some river deltas and lakes by means of Landsat-MSS imagery in combination with field observation and analysis of historical records.The Huang He Delta is fast prograding through the aggradation, shifting and lengthening of its numerous distributaries. It may be considered as the overlapping and coalescing of tens of small individual deltas which can be clearly delineated from the Landsat-MSS imagery. The development of the Chang Jiang Delta is somewhat different. Its channel mouth bar is the focus of the delta growth. The channel mouth bar first becomes an island and then gradually combines with the mainland as one of the passages around it, gradually silting up. So the river mouth island may be considered as a subdelta which will eventually be annexed to the main delta. It can be seen from the Landsat-MSS imagery that the annexation of the Chongming island to the main delta is impending as the passage north of it is silted up while the Changxing island at the mouth of the southern passage is becoming the site of a new subdelta. According to the Landsat-MSS imagery, the Luan He Delta has a strong tectonic control in its development.Along the middle and lower courses of the Chang Jiang River, there are several large lakes which are the resulting from the combined actions of exogenic and endo-genic forces. Among them the Poyang Lake and Dongting Lake are the largest two. The Poyang Lake is inundated by the Chang Jiang River during flood and is largely exposed at low water stage to be crossed by the extended Gan Jiang channel. The Dongting Lake is connected to the Chang Jiang River by four over flow channels which bring large amount of silt to the northern side of the lake. So the lake shrinksin area. The desert lake------Lop Nur has so far been famous as a wandering lake,but in fact it is not wandering. All evidences recealed on the Landsat-MSS imagery and collected in the field indicate that this lake is much affected by climatic fluctuations and neotectonic movements. It gradually shrinks and moves to the west but has never left its downfaulted basin.Landsat-MSS imagery will much promote our researches in various fields of geography and help to realize the ’quantification of geographical phenomena.

Cite this article

Pu Jingjuan, Wang Changyao . STUDIES ON DYNAMICS OF SOME RIVER DELTAS AND LAKES USING LANDSAT-MSS IMAGERY[J]. Acta Geographica Sinica, 1979 , 34(1) : 43 -54 . DOI: 10.11821/xb197901005

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