不同生活型植物非光合部分反射光谱和盖度的关系  

Relationship of reflectance spectral and fractional cover of various non⁃photosynthetic vegetation

作　　者：白雪莲 乔荣荣 季树新 闫志坚[3] 常学礼 赵文智 BAI Xuelian;QIAO Rongrong;JI Shuxin;YAN Zhijian;CHANG Xueli;ZHAO Wenzhi(Linze Inland River Basin Research Station,Chinese Ecosystem Network Research,Key Laboratory of Ecohydrology of Inland River Basin,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China;School of resources and environmental engineering,Ludong University,Yantai 264025,China;Grassland research institute,Chinese Academy of Agricultural Science,Hohhot 010010,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院西北生态环境资源研究院,中国生态系统研究网络临泽内陆河流域研究站,中国科学院内陆河流域生态水文重点实验室,兰州730000 [2]鲁东大学资源与环境工程学院,烟台264025 [3]中国农业科学院草原研究所,呼和浩特010010 [4]中国科学院大学,北京100049

出　　处：《生态学报》2022年第1期186-195,共10页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(41271193);内蒙古自治区十三五水利重大专项项目(NSK2017⁃M2)。

摘　　要：非光合植被(Non⁃photosynthetic Vegetation,NPV)既是陆地生态系统重要组成部分,也是全球C、N平衡分析中关键节点,其盖度是判断我国北方沙尘源区风沙活动强弱的重要指征。基于ASD光谱仪(Analytical Spectral Devices)所测地面高光谱数据对鄂尔多斯沙地草场不同生活型植物(草本、半灌木和灌木)NPV光谱特征进行了分析,构建了干枯燃料指数(Dead Fuel Index,DFI)、纤维素吸收指数(Cellulose Absorption Index,CAI)和NPV盖度(f_(NPV))应用模型,并使用MCD43A4数据在不同草原区进行了验证。结果表明:(1)草本、半灌木、灌木和总体混合NPV光谱反射率具有相似变化趋势,但反射值存在显著差异。(2)DFI和CAI、CAI和f_(NPV)、DFI和f_(NPV)均呈显著正相关关系(P<0.001),DFI可以代替CAI进行f_(NPV)的估算。(3)不同草原区f_(NPV)存在异质性,草甸草原、典型草原、沙地草场和荒漠草原分别为75.95%、50.61%、45.88%和32.77%。DFI在典型草原区估算f_(NPV)效果最好(f_(NPV1)和f_(NPV2)平均差值为3.11%,最小差值为0.03%)。在草原区进行f_(NPV)估算时,不可将NPV作为均质体处理,还要剔除裸地干扰。Non⁃photosynthetic vegetation(NPV)is a vital component of terrestrial ecosystem,as well as a critical hotspot in global carbon and nitrogen studies.In addition,its coverage in the source area of wind⁃blown sand in northern China indicates the intensity of wind⁃blown sand activities.As revealed from recently conducted studies,cellulose absorption index(CAI)was highlighted to be capable of more effectively reflecting the fractional cover of non⁃photosynthetic vegetation(f_(NPV)).However,there was no corresponding band(2000—2050 nm,2080—2130 nm,and 2100—2240 nm)for CAI calculation in the 36 bands of MODIS data.Subsequently,under the introduction of dead fuel index(DFI),it can be employed directly to estimate f_(NPV),whereas a question is whether DFI accurately reflect the content of NPV cellulose?Is it necessary to establish the relationship between CAI and DFI to achieve more accurate estimation of f_(NPV)?It has always been neglected by researchers.Therefore,this paper intended to study the distribution of f_(NPV) in various grassland,and compared the difference between direct estimation of f_(NPV) by DFI and indirect estimation of f_(NPV) by CAI,the influence of bare land on the estimation results were analyzed in order to explain the spatial heterogeneity characteristics of f_(NPV) in different grasslands.We analyzed the NPV spectral characteristics of different habitats NPV(herb,semi⁃shrub and shrub)in sandy grassland of Ordos and constructed the application model of DFI,CAI and f_(NPV) based on the ground hyper⁃spectral data measured by analytical spectral devices,and then validated in different grassland areas.The results showed that the NPV reflectance had similar trends of herb,semi⁃shrub,shrub and mixed NPV.There was a significantly positive correlation between DFI and CAI,CAI and f_(NPV),DFI and f_(NPV) at the level of P<0.001,and DFI could better reflect the change of f_(NPV).But the f_(NPV) value directly calculated by DFI was larger than the f_(NPV) that calculated indirectly by CAI

关 键 词：地面高光谱 非光合植被盖度 干枯燃料指数 纤维素吸收指数 

分 类 号：Q948.1[生物学—植物学]