基于MOD 09GA数据的新疆草地生长状况遥感监测研究

以新疆全区草地为研究对象,利用2010-2014年天然草地地上生物量实测数据(above-ground biomass,AGB)和EOS Terra MODIS每日地表反射率产品MOD 09GA,采用空间分析方法分别计算了生长季(4-10月)草地NDVI_max,MSAVI_max,PVI_max,NDVI_mean,MSAVI_mean和PVI_mean 6种植被指数,探讨了NDVI_max,MSAVI_max,PVI_max与草地地上生物量之间的遥感反演模型,分析了新疆草地生长季多年NDVI_mean,MSAVI_mean和PVI_mean空间分布特征和空间变化特征。根据所选的最优模型反演了新疆2005-2014年的草地地上生物量,统计分析了地上生物量的空间变化特征。结果表明,新疆草地2010-2014年NDVI_mean,MSAVI_mean和PVI_mean总体上均具有由北向南、由西向东逐渐递减的空间分布特点,不同草地类型的生物量差异显著。2005-2014年低地草甸类的生物量最高,高寒荒漠类最低。统计分析2010-2014年的NDVI_mean,MSAVI_mean和PVI_mean变化趋势发现,北疆有28%以上草地处于改善状态,南疆草地则以稳定为主;全疆14个地、州、市草地以稳定为主,处于稳定比重的草地大于40%,博尔塔拉蒙古自治州、哈密地区、塔城地区、巴音郭楞蒙古自治州草地处于改善状态的草地超过15%,阿勒泰地区、博尔塔拉蒙古自治州、伊犁哈萨克自治州直属、克拉玛依市、昌吉回族自治州、克孜勒苏柯尔克孜自治州、阿克苏地区和乌鲁木齐市轻度改善的草地比重大于10%;除吐鲁番市和乌鲁木齐市外,其余地、州、市恶化草地比重低于10%,全疆草地整体改善以稳定为主,总体趋于良好。

Monitoring of grassland herbage accumulation by remote sensing using MOD 09GA data in Xinjiang

This study focuses on grassland in the Xinjiang Uygur Autonomous Region;in situ measurements of above ground biomass (AGB) and its spatial distribution were recorded during the growing seasons from 2010 to 2014.Regression models using AGB data and the corresponding daily surface reflectance obtained remotely from EOS Terra MODIS were established.Spatial analysis was used to calculate six vegetation indices (NDVImax MSAVImax PVImax NDVImean MSAVImean and PVImean) using MOD 09GA data and the accuracy of the inversion models analyzed.The spatial distribution and spatial variation of the NDVImean,MSAVImean and PVI values from 2010 to 2014 were also analyzed.Above-ground grassland biomass and its spatial distribution from 2005 to 2014 were estimated.It was found that NDVI MSAVI and PVI values gradually decreased from South to North and from West to East,and different grassland types have characteristic biomass differences.The biomass of azonal lowland meadow was highest and alpine desert type lowest among the grassland types included in the study.The trend of NDVI MSAVI and PVI value from 2010 to 2014 indicates that over 28％ of regions in North Xinjiang could be categorized as showing'Improvement',whereas in South Xinjiang these indicators were stable.The grassland of 14 prefectures in Xinjiang,representing 40％ of the region,was also stable.The grassland of the Bortala Mongol Autonomous Prefecture,Kumul Prefecture,Tacheng Prefecture and Bayingolin Mongol Autonomous Prefecture showed improvement of over 15％.Over 10％ of the grassland in Altary Prefecture,Bortala Mongol Autonomous Prefecture,Ili Kazakh Autonomous Prefecture,Karamay City,Changji Hui Autonomous Prefecture,Kizilsu Kirghiz Autonomous Prefecture,Aksu Prefecture and Urumqi City can be categorized as showing'Mild Improved'.The overall trend for grassland vegetation in Xinjiang is positive.