基于RS和GIS的乌伦古河流域天然植被生态需水研究

Study on the Ecological Water Requirement for Natural Vegetation in the Ulungur River Basin Based on RS and GIS

基于RS和GIS的技术方法,利用TM数据解译出乌伦古河流域1990年、2000年和2015年三期土地利用分类图,提取流域三期天然植被分布,结合气象站点实测资料,采用FAO56 Penman-Monteith法,通过ArcGIS建模计算研究区天然植被生态需水。结果表明:乌伦古河流域草地、灌丛、森林三种天然植被生态需水量呈先减少后增加的趋势,整个研究时间段(1990~2015年),生态需水量减少了4.48×108 m^3。25年里,可控生态需水的范围内,三种植被的生态需水量都有减少,总生态需水量平均以1792×104 m^3/a减少。流域天然生态需水量呈现东北部青河县山区少、中西部富蕴县和福海县平原区多的特征,且随着海拔的升高天然植被生态需水量呈减少的趋势。前十年的变化剧烈程度要大于后十五年。

Based on the technical methods of RS and GIS,the three-stage land use classification maps of the Ulungur River basin in 1990,2000 and 2015 were interpreted using TM data to extract the natural vegetation distribution in the third stage of the watershed.Combined with the measured data of meteorological stations,the FAO56 Penman-Monteith method was used to calculate the ecological water requirement for natural vegetation in the study area through ArcGIS.The results showed that the ecological water requirement of the three natural vegetations of grassland,shrub and forest in the Ulungur River basin decreased first and then increased.During the entire study period(1990~2015),the ecological water requirement decreased by 448 million m^3.During 25 years,in the range of controllable ecological water demand,the ecological water demand of the three types of vegetation decreased,and the total ecological water demand decreased by an average of 17.92 million m^3/a.The natural ecological water demand of the river basin was characterized by less in the northeast mountainous areas of Qinghe County,more in the midwest of Fuyun County and plain district of Fuhai County.As the altitude increases,the ecological vegetation water demand decreased.The violent change in the first ten years was greater than that in the latter fifteen years.