最近邻河道相对高度及其在中国洪水淹没制图中的应用

Height above nearest drainage and application in flood inundation mapping in China

基于国际上由数字高程模型(digital elevation model,DEM)衍生的最近邻河道相对高度(height above nearest drainage,HAND)概念,采用STRM DEM数据派生了中国1 000和250 m水平分辨率的HAND数据集,并将HAND数据集应用于洪水淹没制图,建立了河道水位相较枯水期上涨1~10 m情景下的中国河道型洪水淹没图库.进一步以淮河一级支流淠河2020年7月大洪水为例,采用遥感提取及HEC-RAS计算的淹没范围,验证了基于HAND绘制的淹没图.结果表明,HAND相对于经典的DEM能够补充提供局地地形信息,基于HAND的淹没制图方法具有可行性和合理性.本文计算的中国HAND数据集可为地理学相关领域的研究提供凸显局地特征的地形数据,建立的基于HAND的淹没图库可为中国的洪水淹没制图工作及洪水风险管理提供参考.

Local topography,a major governing factor of surface water movement,plays important roles in hydrological responses and associated geographical and ecological processes.But data sets highlighting local topographic characteristics covering contiguous China are lacking,let alone its wide applications.The height-abovenearest-drainage(HAND) concept,which derived from classical digital elevation model(DEM),was used to produce HAND data set for China with grid sizes of 250 and 1 000 m by SRTM DEM,then HAND data were applied for inundation mapping.Library of inundation maps for scenarios of water level rise of 1-10 m from low-flow condition along rivers and streams were developed.Such maps cover contiguous China with horizontal resolutions of 250 and1 000 m.The great flood with peak discharge in July of 2020 along Pi River tributary of Huai He River was studied.The inundated areas retrieved from SAR images on July 20th of 2020 and simulated by HEC-RAS were compared with HAND-based inundation maps.Complementary to DEM with overall features of topography,HAND was found to signify local topographic characteristics over large regions.HAND could therefore be used as a simple but feasible and reliable approach,to map flooded areas.HAND data set of China produced in this work highlights localized topography for geography-related research.HAND-based inundation maps may shed light into flood risk management in China.