灌木扩张背景下的干旱/半干旱草原灌草混合景观植被盖度遥感反演研究

项目名称： 灌木扩张背景下的干旱/半干旱草原灌草混合景观植被盖度遥感反演研究

项目编号： No.41201329

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 地理学

项目作者： 曹鑫

作者单位： 北京师范大学

项目金额： 25万元

中文摘要： 在全球变化背景下，干旱/半干旱草原区域的灌木扩张对当地生态系统产生了重大影响，研究灌草混合植被景观的灌木识别、提取植被盖度及其变化信息对于揭示灌木扩张的发展态势和机理、治理土壤侵蚀及草原退化具有重要意义。本研究拟选取内蒙古锡林郭勒典型草原的灌木扩张区域，通过实测盖度数据和植被冠层多角度光谱测量，根据植被生长周期，建立动态灌草混合植被冠层场景模型及3D辐射传输模型；同步考虑LAI与植被盖度对光谱的综合影响，利用Landsat ETM+及MISR数据，发展LAI-植被盖度同步反演及灌草分离反演技术，实现对灌木的识别并估算其盖度；对辐射传输模型、经验模型及混合像元分解法估算植被盖度进行比较研究，揭示各种方法的适用范围和条件。该研究可为全球气候变暖背景下草原灌丛化的监测和模拟提供科学依据，为防治灌木扩张和治理草原退化提供指导。

中文关键词： 植被盖度；叶面积指数；灌木；3D 辐射传输模型；植被结构参数

英文摘要： The global warming and climate change has been resulting in significant alterations in arid and semi-arid grasslands. Shrub expansion (also called shrub encroachment or shrub invasion) into arid and semiarid grasslands or savannas has been occurring around the world. It presents a serious issue to the earth system because the consequence is not only for the natural environment but also for the socio-economic system. In order to reveal the process and mechanism of shrub extension, and to manage the soil erosion and grassland degradation, it is important to identify the shrub, estimate the coverage of the shrub, and monitor the change of the shrub in the grass-shrub mixture landscape in the grassland. In this research, we select the grassland at Xilin Gole, Inner Mongolia, where the extension of Caragana microphylla is very popular, as the study area to study the methodology of extracting shrub and estimating the vegetation coverage using moderate spatial resolution remotely sensed data. The methodology includes 1) field measurement of vegetation parameters to build the canopy 3D model and dynamic spatial model of grass-shrub mixture landscape, 2) based on a 3D radiative transfer model, developing the LAI-coverage synchronous inversion technology and grass-shrub separation inversion algorithm to extract shrub from

英文关键词： vegetation coverage;；LAI；shrub；3D radiative transfer model；vegetation structure