青海湖及其周围地区沙化土地变化动态研究

青海湖地区生态环境的变化对中国乃至全球的生态变化都有指示意义,为了定期掌握本省荒漠化土地和沙化土地的现状及动态变化信息,为国家和本省制定防沙治沙与防治荒漠化的政策和长远发展规划,保护、改良和合理利用国土资源提供基础资料。本研究采用高分辨率遥感数据判读与地面调查相结合,在现状调查统计的基础上,统计各类型荒漠化和沙化土地面积的监测方法。与1994年、1999年、2004年、2009年连续四次沙化土地监测结果进行对比分析,青海湖及其周围地区从最近20年5次沙化土地监测结果看,在1999年之前的5年沙化土地是发展的,年均速率达到了2.7%,是有监测数据以来沙化土地发展速度最快的。在其之后的15年保持持续逆转的态势,逆转速率在0.25%~2.3%之间,逆转速度逐步减缓,小有起伏。同时尽管沙化土地总体在逆转,但局部地段仍在扩大,而且沙化土地面积占到区域陆地面积21.4%,流动沙地和半固定沙地占沙化土地总面积的42.6%,而露沙地和有明显沙化趋势的土地面积较大,比例较高,沙化土地的逆转具有很大的脆弱性,可逆性高。

Study on the dynamic change of desertification land in the Qinghai Lake and its surrounding area

Changes in the ecological environment in the Qinghai Lake region has important implications of China and the global ecological changes,in order to grasp the province desertification land and land desertification status and dynamic change information regularly,for the state and the province formulated to prevent desertification and desertification control policy and long-term development planning,protection,improvement and rational utilization of land and resources to pro-vide the basic data. In this study,the high resolution remote sensing data interpretation and the ground survey,based on the survey and statistics,statistics of various types of desertification and desertification land area of the monitoring meth-od. Taking the comparison and analysis on the sandy land monitoring results in 1994,1999,2004 and 2009,and 5 times in the last 20 years for sandy land monitoring results in the Qinghai Lake and its surrounding area,in 5 years before 1999 of land desertification is the development and annual rate of 2.7%,it is the fastest development speed of sandy land mo-nitoringdatasince.Inthe15yearsafteritssustainedreversalofthesituation,thereversalrateof 0.25%~2.3%,the reversal rate gradually slowed down,little ups and downs. Also although desertification land overall in reverse,but lots of locals still expanding and desertified land area accounted for 21.4%of the regional land area,the shifting and semi fixed sandy land accounted for 42.6% of the total area of desertified land,and exposed sand and obvious trend of desertifica-tion land area larger,higher proportion,reversion of land desertification has very fragile and reversible.