강화도 조간대 조류로 특성 파악을 위한 Landsat TM/ETM+와 IKONOS 영상의 활용

Abstract

Distribution of channels, exposure time and topographic relief are primary control factors to living organism in tidal flat. Among them, tidal channels which flow bidirectional according to the tide condition have great influence on sedimentation and/or erosion of sediment and distribution of plant species. To monitor characteristics of channel in tidal flat, it is necessary (i) to measure the ‘channel influence’ at vegetation zone and non-vegetation zone; (ii) to understand the difference of channel pattern according to the dominant sediment flat and topographic relief; (iii) to detect change of channels for a long term. To understand characteristics of tidal channel we selected Ganghwa tidal flat on the west coast of the Korean Peninsular has high dynamics of tidal currents and vast tidal flats. Land reclamation which has occurred on a large scale is considered one of elements which accelerated environmental changes in this tidal flat. In this study, we extracted tidal channels using 4m spatial resolution IKONOS to understand length, order and shape of channels. Channel density map was generated to measure ‘channel influence’ quantitatively. This result was compared with DEM (Digital Elevation Model) which was generated from Landsat TM/ETM+ images, grain size and track of vegetation boundary which were obtained from field survey. The result of Ganghwado southern tidal channels and Yeongjondo northern tidal channels showed different characteristics. Tidal channels in the Yeongjongdo northern tidal flat was very complex which have 5 orders. This area which was classified clay dominant tidal flat is relatively high altitude and steep gradient. Tidal channels in the Ganghwado southern tidal flat was simple pattern which have 3 orders. This area which was graded sand dominant tidal flat is relatively low altitude and gentle gradient