【摘要】 利用1982—2000年NOAA/AVHRR第1通道、第2通道和NDVI的旬资料反演得到的藏北那曲地区历年植被覆盖度、年最大牧草鲜质量和6—9月平均改进型土壤调节植被指数,分析了近20年来那曲地区草地荒漠化的动态变化规律.结果表明:以草地荒漠化评价"基准"和5年滑动平均的方法,得到那曲地区近20年平均草地退化面积占土地总面积的43.1%,草地退化面积总体呈减少趋势,其中前10年呈减少趋势,后10年呈增加趋势,西部地区的退化面积大于其它地区.在气温、降水、潜在蒸散、水汽压、风速、日照时数、降水蒸散比和温度降水比8个气候因子中,潜在蒸散量对草地退化面积的影响最显著.更多还原

【Abstract】 Based on the past years vegetation cover,annual maximal grass yield and June-September mean modified soil-adjusted vegetation index(MSAVI) that were inversely deduced from the 10-day composite data of NOAA/AVHRR channels 1 and 2 and NDVI in 1982-2000,this paper analyzed the recent 20 years dynamics of grassland desertification in Naqu of northern Tibet.The results showed that in recent 20 years,the area of degraded grassland in Naqu was averagely 43.1% of the total land area.It was decreased in the former ten years while increased in the latter ten years,but overall,had a decreasing trend.The degraded area was larger in west part of Naqu than in its other regions.Among the eight climatic factors including temperature,precipitation,potential evapotranspiration,vapor pressure,wind velocity,sunshine hour,ratio of precipitation to evapotranspiration,and ratio of temperature to precipitation,the most remarkable factor affecting the dynamic of grassland degradation was the potential evapotranspiration.更多还原