2013—2014年西藏阿里西部地区雪被覆盖遥感动态监测

Snow cover remote sensing monitoring in the west of Ngari area in northern Tibet from 2013 to 2014

利用2013年1月—2014年12月Landsat ETM和OLI中等分辨率卫星遥感数据,开展了西藏阿里西部地区雪被覆盖遥感监测。通过统计计算,总结了2013—2014年监测区内雪被覆盖面积的变化特点;依托气温数据分析了雪被覆盖面积变化与气温升降间的对应关系。结果表明：每年雪被覆盖范围最大时间为2月立春节气前后10 d,覆盖百分比最大达到80.82%;而雪被覆盖范围最小时间为8月立秋节气前后10 d,覆盖百分比最小只有0.77%。从年度周期来看,雪被覆盖范围从最大到最小的变化经历了6~7个月,是个相对渐变的过程;雪被覆盖范围达到最小后将经历一个上下波动过程,历时4~5个月;雪被覆盖范围从上下波动到最大覆盖范围是相对骤变的过程,只经历了约1个月。

Based on medium resolution satellite remote sensing （RS） data Landset ETM and OLI from 2013 to 2014, the authors conducted snow cover RS monitoring in the west of Ngari area in northern Tibet. Changing characteristics of snow - covered area over the two years were summed up by utilizing the statistical calculation method. Using the air temperature data, the authors studied in detail the corresponding rule between the snow - covered area changes and the air temperature value changes. Some conclusions have been reached： Every year the maximum period of the snow - covered area is from January to February, about 10 days before or after the beginning of spring. The maximum percentage of the snow - covered area reaches 80.82 percent. The minimum period of the snow - covered area is August, about 10 days before or after the beginning of autumn. The minimum percentage of the snow - covered area is only 0.77 percent. Annually, the decrease from the maximum percentage of the snow - covered area to the minimum percentage lasts for 6 - 7 months, which is a relatively gradual process. In the second stage, there is a fluctuation percentage of the snow - covered area for about 4 - 5 months. At last, the increase from the fluctuation percentage to the maximum percentage is a relatively drastic process lasting for 1 month or so.