温带草原放牧场积雪灾害分级评价的遥感分析

冬春季持续性大面积过厚积雪是造成温带草原放牧场积雪灾害的主要致灾因子．以积雪灾害频繁发生的内蒙古锡林郭勒草原的部分地区为研究区域，分析了该区域的孕究环境和影响积雪灾害危害程度的因子系统．同时应用陆地资源卫星Ｌａｎｄｓａｔ－ＴＭ影像对承灾体，即放牧草场的类型；ＮＯＡＡ－ＡＶＨＲＲ资料对致灾因子和积雪的分布及深度状况进行了监测．在积雪深度遥感信息提取时，与接收ＮＯＡＡ气象卫星资料准同步，通过将研究区草场类型图和雪深图叠加，得出１９９２年冬季以积雪掩埋牧草高度的百分比共分四级，即无白灾，轻度白灾，中度白灾和严重白灾，并量算出各雪灾等级的面积．最后提出了今后应进一步加强关于减灾抗灾措施的几点建议．

Remote Sensing Analysis on Grade Evaluation of Accumulated Snow Disaster in Temperate Rangeland

Too much thicker continuous accumulated snow in winter and spring is a main factor causing snow disaster in temperate rangeland. A part of Xilin Gol steppe in Net Monggol where snow disaster often occurs is selected,as the study area. The pregnancy environment of snow disaster and the factor system impacting the extent of injury of snow disaster are analysed. In the meanwhile,by using Landsat-TM image and NOAA-AVHRR,the types of grazing rangeland and snow cover are respectively monitored. In the research, the methodology of combining the remote sensing technology and ground survey is used. Especially while monitoring the snow depth,synchronizing with the reception of NOAA-AVHRR data,snow depths in 40 spots in the study area are measured the statistics model between snow depth and snow depth index is build up through regression analysis. Through overlaying the rangoland types map and the snow depth map,the snow disaster grade map which uses the percentage of snow hiding the forage height as grade index is drawn,and there four grades:no snow disaster,light snow disaster,medium snow disaster and serious snow disaster,and the area of each grade snow disaster is measured. At last,some measures of lightening snow disaster and anti-snow disaster are put forward.