ISLSCP II GIMMS MONTHLY NDVI, 1981-2002

The Global Inventory Modelling and Mapping Studies (GIMMS) Normalized Difference Vegetation Index (NDVI) data sets were generated to provide a 22-year satellite record of monthly changes in terrestrial vegetation. This data set contains three data files provided at spatial resolutions of 0.25, 0.5 and 1.0 degree in latitude and longitude with data from July 1981 through December 2002. New features include reduced NDVI variations arising from calibration, view geometry, volcanic aerosols, and other effects not related to actual vegetation change. In particular, NOAA-9 descending node data from September 1994 to January 1995, volcanic stratospheric aerosol correction for 1982-1984 and 1991-1994, and improved NDVI using empirical mode decomposition/reconstruction (EMD) to minimize effects of orbital drift. Global NDVI was generated to provide inputs for computing the time series of biophysical parameters contained in the International Satellite Land Surface Climatology Project (ISLSCP) Initiative II collection. NDVI is used in climate models and biogeochemical models to calculate photosynthesis, the exchange of CO2 between the atmosphere and the land surface, land-surface evapotranspiration and the absorption and release of energy by the land surface.全球清查建模与制图研究（Global Inventory Modelling and Mapping Studies, GIMMS）归一化植被指数（Normalized Difference Vegetation Index, NDVI）数据集旨在提供一套时长22年的陆地植被月度变化卫星观测记录。本数据集包含三个数据文件，空间分辨率分别为经纬度0.25°、0.5°与1.0°，数据时间跨度为1981年7月至2002年12月。其新特性在于：修正了由定标、观测几何、火山气溶胶及其他与实际植被变化无关的因素所引发的NDVI波动。具体而言，研究团队对1994年9月至1995年1月的NOAA-9降交点数据进行了优化处理，对1982-1984年及1991-1994年的平流层火山气溶胶实施了校正，并通过经验模态分解/重构（Empirical Mode Decomposition/Reconstruction, EMD）优化NDVI数据，以最大程度削弱轨道漂移带来的影响。本全球NDVI数据集的构建，旨在为计算国际卫星陆地表面气候学计划（International Satellite Land Surface Climatology Project, ISLSCP）第二倡议（Initiative II）合集所收录的生物物理参数时间序列提供输入数据。NDVI常被应用于气候模型与生物地球化学模型中，用于计算光合作用、大气与陆地表面间的CO₂交换、陆地表面蒸散量以及陆地表面的能量吸收与释放过程。