Google Earth Engine ——MOD17A3H.006: Terra Net Primary Production Yearly Global 500m这是该产品的NASA版本年度净初级

The MOD17A3H V6 product provides information about annual Net Primary Productivity (NPP) at 500m pixel resolution. Annual NPP is derived from the sum of the 45 8-day Net Photosynthesis (PSN) products (MOD17A2H) from the given year. The PSN value is the difference of the GPP and the Maintenance Respiration (MR) (GPP-MR).

This is a NASA version of this product. Another version is produced by the Numerical Terradynamic Simulation Group (NTSG), University of Montana (UMT). The NTSG version corrects the problem with cloud-contaminated MODIS LAI-FPAR inputs to the MOD17 algorithm, but its resolution is 1km. It is ingested into Earth Engine as MODIS/055/MOD17A3.

For further details regarding the differences between the NTSG and NASA versions of this product, please consult this document .

MOD17A3H V6产品提供500米像素分辨率的年度净初级生产力（NPP）信息。年净初级生产力是由给定年份的45个8天净光合作用（PSN）产品（MOD17A2H）之和得出的。PSN值是GPP和维持呼吸（MR）之差（GPP-MR）。

这是该产品的NASA版本。另一个版本是由蒙大拿大学（UMT）的数字地球动力学模拟小组（NTSG）制作的。NTSG版本纠正了MOD17算法中被云层污染的MODIS LAI-FPAR输入的问题，但其分辨率为1公里。它作为MODIS/055/MOD17A3被录入地球引擎。

关于该产品的NTSG和NASA版本之间的差异的进一步细节，请参考该文件。

Dataset Availability

2000-01-01T00:00:00 - 2014-01-01T00:00:00

Dataset Provider

NASA LP DAAC at the USGS EROS Center

Collection Snippet

ee.ImageCollection("MODIS/006/MOD17A3H")

Resolution

500 meters

Bands Table

使用说明：

MODIS data and products acquired through the LP DAAC have no restrictions on subsequent use, sale, or redistribution.

数据引用：

LP DAAC - MOD17A3H

代码：

var dataset = ee.ImageCollection('MODIS/006/MOD17A3H')
                  .filter(ee.Filter.date('2014-01-01', '2015-05-01'));
var npp = dataset.select('Npp');
var nppVis = {
  min: 0.0,
  max: 19000.0,
  palette: ['bbe029', '0a9501', '074b03'],
};
Map.setCenter(6.746, 46.529, 2);
Map.addLayer(npp, nppVis, 'NPP');