Acta Geographica Sinica ›› 2012, Vol. 67 ›› Issue (3): 377-387.doi: 10.11821/xb201203009

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Monitoring Change and Position of Coastlines from Satellite Images Using Slope Correction in a Tidal Flat: A Case Study in the Yellow River Delta

LIU Yanxia1, HUANG Haijun1, QIU Zhongfeng2, CHEN Jitao3, YANG Xiguang1   

  1. 1. Institute of Oceanology, CAS, Qingdao 266071, Shandong, China;
    2. College of Marine Science, Nanjing University of Information and Technology, Nanjing 210044, China;
    3. Yellow River Conservancy Commission, Shandong Bureau of Hydrology and Water Resources, Jinan 250100, China
  • Received:2011-10-18 Revised:2011-11-09 Online:2012-03-20 Published:2012-03-20
  • Supported by:
    Knowledge Innovation Program of Chinese Academy of Sciences, No. KZCX2-EW-207; National Natural Science Foundation of China, No.40676037; No.40706035; No.41076031; No.41106041

Abstract: Tidal and landform variations have a significant impact on detection of coastline changes in a tidal flat environment. This paper presents a slope correction method of determining 1985 national height datum shoreline positions from two satellite images that take into account tidal variations. Furthermore, volumes of tidal flats are calculated by tidal flat gradient. Combination of remote sensing images, the measured cross-section data and depth measurement data analysis showed that although the inter-tidal range of the image has a greater impact on gradient estimates, estimation of tidal gradient is feasible by choosing appropriate images. The minimum error of consistency check is up to about 0.2% of estimate gradient, and root mean square error of absolute check is less than the measured gradient in an order of magnitude. Muddy-silt tidal flats were used to test this method in the south coastal area of the Yellow River Delta. Multitemporal remote sensing data of Landsat MSS and TM/ETM from 1973 to 2009, totaling 14 years, were used to examine the changing pattern of erosion and accretion of the tidal flat from Tianshuigou to Xiaoqing River estuary. Since the diversion of the Yellow River in 1976, the sediment of the river is deposited directly about 3 km from Tianshuigou southward in the study area. The maximum accretion occurs near the Tianshuigou where the coastline advanced seaward over 0.7 km with a mean net accretion rate of 31 m/a. During the period 1989-2002, rapid sedimentation happened in the southern part of the study area. Accumulation of sediment and resuspended sediment from the Yellow River is the major driving force. From 1973 to 2009, the general tendency of coastline was erosive with a mean net rate of 51 m/a. The enhanced ocean dynamics caused by the diversion of the Yellow River is the main reason. It is indicated that the volume of tidal flats is reasonable and reliable for detecting shoreline change.

Key words: coastline, gradient of tidal flat, erosion and accretion, remote sensing, Yellow River Delta