2001-2010年青藏高原草地生长状况遥感动态监测

Remote sensing dynamic monitoring of grass growth in Qinghai-Tibet plateau from 2001 to 2010

基于1970个地面实测数据,结合MODIS EVI和NDVI数据,利用留一法交叉验证方法确定了适合青藏高原地区草地生长状况的遥感反演模型,估算了2001-2010年草地生物量干重空间分布格局,分析了近10年草地生物量变化动态.结果表明:青藏高原地区MODIS的NDVI较EVI能更好地估算草地生长状况,指数模型反演的草地鲜重和风干重精度最高,而盖度反演适合使用乘幂模型;确立了基于MODIS-NDVI的青藏高原地区草地鲜重、风干重和盖度反演模型;青藏高原地区2001-2010年草地地上生物量总体有增加趋势,但不显著;月际变化较大的草地类型主要有沼泽类、山地草甸类和高寒草甸类.

Using leave-one-out cross validation method,a suitable inversion model was established in Qinghai-Tibet plateau based on 1970 ground observed data combined with MODIS EVI and NDVI data.Then the spatialdistribution pattern of grassland dry biomass during 2001-2010 was simulated and grassland biomass dynamicsfor nearly 10 years was analyzed.The results show that NDVI is superior to EVI in Qinghai-Tibet plateau,theexponential model has the highest accuracy for calculating fresh and dry biomass,but the power model is bestfor calculating the coverage.The fresh,dry biomass and coverage inversion models based on MODIS-NDVI datawere established.The grassland aboveground biomass shows an increasing trend but it is not obvious.Marsh,mountain meadow and alpine meadow have a larger monthly change.