黄河清水沟改道以来河口新生湿地动态监测研究

利用1976-12-2003-01共22个时相的卫星遥感数据,以及GIS空间分析手段,对黄河清水沟改道以来河口新生湿地的时空动态进行了系统研究。通过对不同时相遥感影像的目视解译获得水陆界限,在GIS支持下对研究区内的水陆边界进行比较,确定侵蚀区和淤积区,并计算其面积。结果表明,在黄河泥沙沉积和海洋侵蚀的双重作用下,河口新生湿地的增加和减少交替进行,且近年来净增加面积呈现减少趋势。27年余净增加河口新生湿地17154.41hm₂,1993年以前为净增加,此后则逐步减少。1993年之前的增加部位为新河口区和东南沿海区,减少部位在老河口区,之后则老河口区增加,新河口区和东南沿海区减少。

Dynamic Monitoring of Newborn Estuary Wetland since Channel Diversion of the Yellow River to Qingshuigou

Using remote sensing data from Dec.1976 to Jan.2003 and spatial analysis of GIS,this paper analyses the dynamic change of the newborn estuary wetland since channel diversion of the Yellow River to Qingshuigou.The research area is a sector area,composing of three evident objects:a Yellow River inflexion near Kenli County government,northwest inflexion of Guhe reservoir and northeast inflexion of Guangbei reservoir.By the visual interpretation of remote sensing images at different phases,we can get the borderline between land and ocean.Comparing the borderlines of the research area supported by GIS,the areas of siltation and erosion can be identified and their scope can be computed.The results indicate that the increase and decrease of newborn estuary wetland are ongoing alternately because of the Yellow River siltation and the ocean erosion,and the area of net increase is declining gradually.Within 26 years,the newborn estuary wetland got a net increase of 17 154.41ha,and the annual average net increase is 657.76ha.The wetland area was a net increase before 1993,while this net increasing trend declined gradually after 1993.At the same time,the alternative periods of increase and decrease of the newborn wetland become shorter and shorter from 2.52 years to 1.06 years.Before 1993,the increased parts are located in the new estuary region and southeast coastal zone,and the decreased area located in the old estuary region.After 1993,the variational trend of the above two regions are reversed.The main reason is due to the influence of the Yellow River siltation and the ocean erosion.This study will provide suggestions on decision,making for the wetland protection of the Yellow River delta.