MODIS Collection 6.1 global yearly gap-filled Gross and Net Primary Production

<strong>Abstract:</strong> MODIS Collection 6.1 yearly gap-filled Gross Primary Production (GPP) and Net Primary Production (NPP) data on the MODIS sinusoidal grid are taken from the netCDF files produced at ICDC, for which the bit-encoded quality information given in the HDF-files was already decoded, and re-gridded to build a global map of grid-cell mean GPP and NPP and their variances on a global equirectangular climate modeling grid (CMG). Only those GPP or NPP values are used where i) the cloud flag indicates either clear sky or assumed clear sky, where the MODLAND quality is good and where the confidence flag suggests best quality or good quality data. The confidence flag is provided as a grid-cell mean rounded value with fractions of the five original flags being provided for convenience. Cloud conditions are included in form of the primary cloud flag and the fraction this primary cloud flag occupies among the valid 500 m sinusoidal grid grid cells. Two separate layers of the number of valid grid cells of the 500 m sinusoidal grid are given, one is for the geophysical data and one is for the flags.

<strong>TableOfContents:</strong> grid cell mean Gross_Primary_Production (GPP); grid cell mean Net_Primary_Production (NPP); GPP standard deviation over grid cell; NPP standard deviation over grid cell; number of valid used GPP or NPP values per grid cell; number of valid used confidence and quality flag values per grid cell; grid cell mean confidence flag; fraction of confidence flag 0 in grid cell; fraction of confidence flag 1 in grid cell; fraction of confidence flag 2 in grid cell; fraction of confidence flag 3 in grid cell; fraction of confidence flag 4 in grid cell; primary cloud flag; primary cloud flag fraction

<strong>Technical Info:</strong> dimension: 720 columns x 360 rows x unlimited; temporalExtent_startDate: 2001-01-01; temporalExtent_endDate: 2023-12-31; temporalResolution: Yearly; spatialResolution: 0.5; spatialResolutionUnit: degrees; horizontalResolutionXdirection: 0.5; horizontalResolutionXdirectionUnit: degrees; horizontalResolutionYdirection: 0.5; horizontalResolutionYdirectionUnit: degrees; verticalResolution: none; verticalResolutionUnit: none; verticalStart: none; verticalEnd: none; instrumentName: MODerate Resolution Spectroradiometer (MODIS); instrumentType: visible_to_infrared_spectroradiometer; instrumentLocation: Earth Observation Satellite (EOS) Terra; instrumentProvider: NOAA/NASA 

<strong>Methods:</strong> [1] Running, S. W., and M. Zhao, Users Guide Daily GPP and Annual NPP (MOD17A2H/A3H) and Year-end Gap-Filled (MOD17A2HGF/A3HGF) Products NASA Earth Observing System MODIS Land Algorithm, (For Collection 6), Version 4.0, January 2, 2019; [2] Running, S. W., R. R. Nemani, F. A. Heinsch, M. Zhao, M. Reeves, and H. Hashimoto, A continuous satellite-derived measure of global terrestrial primary production. Bioscience, 54(6), 547-560, 2004; [3] Running, S. W., A measurable planetary boundary layer for the biosphere. Science, 337(6101), 1458-1459, 2012; [4] Zhao, M., F. A. Heinsch, R. R. Nemani, and S. W. Running, Improvements of the MODIS terrestrial gross and net primary production global data set. Remote Sensing of Environment, 95(2), 164-176, 2005

<strong>Units:</strong> Units for all variables (see TableOfContents): kg C m-2; kg C m-2; kg C m-2; kg C m-2; 1; 1; 1; percent; percent; percent; percent; percent; 1; percent

<strong>geoLocations:</strong> westBoundLongitude: -180.0 degrees East; eastBoundLongitude: 180.0 degrees East; southBoundLatitude: -90.0 degrees North; northBoundLatitude: 90.0 degrees North; geoLocationPlace: global on land

<strong>Size: </strong>(files are packed into one zip-archive)

2001-2023: 1 file per year, each approximately 12975000 bytes

<strong>Format:</strong> netCDF

<strong>DataSources:</strong>

Original data on sinusoidal grid tiles in hdf-format: https://doi.org/10.5067/MODIS/MOD17A3HGF.061 (last accessed: 2024-06-03), see also https://lpdaac.usgs.gov/products/mod17a3hgfv061/ (last accessed: 2024-06-03)

Data on sinusoidal grid tiles in netCDF format: https://www.cen.uni-hamburg.de/en/icdc/data/land/modis-primaryproduction.html (last accessed: 2024-07-09) or https://doi.org/10.25592/uhhfdm.14633 (last accessed: 2024-07-09).

<strong>Contact:</strong> stefan.kern (at) uni-hamburg.de

<strong>Web page:</strong> https://www.cen.uni-hamburg.de/en/icdc/data/land/modis-primaryproduction.html (last accessed: 2024-07-09)

<strong>摘要:</strong> 本数据集采用国际气候数据中心（ICDC）生成的netCDF文件中的MODIS正弦格网年际间隙填充总初级生产力（Gross Primary Production, GPP）与净初级生产力（Net Primary Production, NPP）数据，其中HDF文件中附带的比特编码质量信息已完成解码，并通过重格网化处理，基于全球等距圆柱气候建模格网（CMG）生成格网平均GPP、NPP及其方差的全球分布图。仅保留满足以下全部条件的GPP与NPP数值：①云标识指示晴空或推定晴空；②MODLAND质量等级为优；③置信标识对应最优质量或良好质量数据。本次处理将置信标识处理为格网平均取整值，并附带5种原始置信标识的占比以方便使用。云况信息以主云标识及其在有效500米正弦格网单元中的占比形式提供。数据集提供两组独立的500米正弦格网有效单元数量图层，分别对应地球物理数据与标识数据。
<strong>目录:</strong> 格网平均总初级生产力（GPP）；格网平均净初级生产力（NPP）；格网GPP标准差；格网NPP标准差；每个格网的有效GPP/NPP数值数量；每个格网的有效置信与质量标识数值数量；格网平均置信标识；格网中置信标识0的占比；格网中置信标识1的占比；格网中置信标识2的占比；格网中置信标识3的占比；格网中置信标识4的占比；主云标识；主云标识占比
<strong>技术信息:</strong> 维度：720列×360行×不限定维度；时间范围起始日期：2001-01-01；时间范围结束日期：2023-12-31；时间分辨率：年际；空间分辨率：0.5；空间分辨率单位：度；X方向水平分辨率：0.5；X方向水平分辨率单位：度；Y方向水平分辨率：0.5；Y方向水平分辨率单位：度；垂直分辨率：无；垂直分辨率单位：无；垂直起始值：无；垂直结束值：无；仪器名称：中分辨率成像光谱仪（MODerate resolution Spectroradiometer, MODIS）；仪器类型：可见-红外分光辐射计；仪器搭载平台：地球观测卫星（EOS）Terra；数据提供方：美国国家海洋和大气管理局/美国国家航空航天局（NOAA/NASA）
<strong>方法:</strong> [1] Running, S. W., 与 M. Zhao，《用户指南：日度GPP与年度NPP（MOD17A2H/A3H）及年末间隙填充（MOD17A2HGF/A3HGF）产品 NASA地球观测系统MODIS陆地算法（第6版数据集）》，版本4.0，2019年1月2日；[2] Running, S. W., R. R. Nemani, F. A. Heinsch, M. Zhao, M. Reeves, 与 H. Hashimoto，《基于卫星连续观测的全球陆地初级生产力测量方法》，《生物科学》，54(6)，547-560，2004年；[3] Running, S. W.，《生物圈可测量的行星边界层》，《科学》，337(6101)，1458-1459，2012年；[4] Zhao, M., F. A. Heinsch, R. R. Nemani, 与 S. W. Running，《MODIS陆地总与净初级生产力全球数据集的改进》，《环境遥感》，95(2)，164-176，2005年
<strong>单位:</strong> 所有变量单位（详见目录）：千克碳每平方米（kg C m⁻²）；千克碳每平方米；千克碳每平方米；千克碳每平方米；无量纲；无量纲；无量纲；百分比；百分比；百分比；百分比；百分比；无量纲；百分比
<strong>地理覆盖范围:</strong> 西边界经度：-180.0度东经；东边界经度：180.0度东经；南边界纬度：-90.0度北纬；北边界纬度：90.0度北纬；覆盖区域：全球陆地区域
<strong>数据量:</strong> （所有文件打包为单个ZIP压缩包）
2001-2023年：每年1个文件，每个文件大小约12975000字节
<strong>数据格式:</strong> netCDF
<strong>数据源:</strong> 原始正弦格网分幅HDF格式数据：https://doi.org/10.5067/MODIS/MOD17A3HGF.061（最后访问时间：2024-06-03），另见https://lpdaac.usgs.gov/products/mod17a3hgfv061/（最后访问时间：2024-06-03）；正弦格网分幅netCDF格式数据：https://www.cen.uni-hamburg.de/en/icdc/data/land/modis-primaryproduction.html（最后访问时间：2024-07-09）或https://doi.org/10.25592/uhhfdm.14633（最后访问时间：2024-07-09）
<strong>联系方式:</strong> stefan.kern (at) uni-hamburg.de
<strong>数据集官网:</strong> https://www.cen.uni-hamburg.de/en/icdc/data/land/modis-primaryproduction.html（最后访问时间：2024-07-09）