Google Earth Engine——NOAA气候数据记录（CDR）的AVHRR叶面积指数（LAI）和吸收光合有效辐射的部分（FAPAR）数据集包含描述植物冠层和光合活动的衍生值

The NOAA Climate Data Record (CDR) of AVHRR Leaf Area Index (LAI) and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) dataset contains derived values that characterize the canopy and photosynthetic activity of plants. This dataset is derived from the NOAA AVHRR Surface Reflectance product and is gridded at a resolution of 0.05° on a daily basis. The values are computed globally over land surfaces, but not over bare or very sparsely vegetated areas, permanent ice or snow, permanent wetland, urban areas, or water bodies.

Known issues with this dataset include:

• TIMEOFDAY variable contains values that are too large by 1 day

• Latitude values are not correctly associated with the center of the grid cell, error is < 0.002 degrees

• Longitude values are not correctly associated with the center of the grid cell, error is < 0.02 degrees

See technical note from the data provider.

NOAA气候数据记录（CDR）的AVHRR叶面积指数（LAI）和吸收光合有效辐射的部分（FAPAR）数据集包含描述植物冠层和光合活动的衍生值。该数据集来自NOAA AVHRR表面反射产品，并以0.05°的分辨率按日进行网格化。这些数值是在全球范围内计算的，但不包括光秃秃的或植被非常稀少的地区、永久的冰或雪、永久的湿地、城市地区或水体。

这个数据集的已知问题包括。

TIMEOFDAY变量所包含的数值过大，超过1天。

纬度值与网格单元的中心没有正确关联，误差<0.002度

经度值与网格单元的中心没有正确关联，误差< 0.02度

见数据提供者的技术说明。

Resolution

5566 meters

Bands Table

Name	Description	Min*	Max*	Scale
LAI	Leaf area index	0	6205	0.001
FAPAR	Fraction of absorbed photosynthetic active radiation	0	896	0.001
QA	Quality control bit flags			0
QA Bitmask	Bits 0-1: Quality control 0: Ok 1: Input flags as cloudy 2: Invalid input 3: Output out of range Bits 2-4: Associated class 1: Needleleaf forest 2: Broadleaf forest 4: Grassland & croplands & non vegetated 5: Evergreen broadleaf forest 6: Water Bit 5: BRDF corrected 0: No 1: Yes Bits 6-7: Polygon test 0: In polygon 1: Not in polygon 2: Not tested (water/cloudy)

* = Values are estimated

CLOSEIMPORT

影像属性：

Name	Type	Description
status	String	'provisional' or 'permanent'

引用：

The NOAA CDR Program’s official distribution point for CDRs is NOAA’s National Climatic Data Center which provides sustained, open access and active data management of the CDR packages and related information in keeping with the United States’ open data policies and practices as described in the President's Memorandum on "Open Data Policy" and pursuant to the Executive Order of May 9, 2013, "Making Open and Machine Readable the New Default for Government Information". In line with these policies, the CDR data sets are nonproprietary, publicly available, and no restrictions are placed upon their use. For more information, see the Fair Use of NOAA's CDR Data Sets, Algorithms and Documentation pdf.

Martin Claverie, Eric Vermote, and NOAA CDR Program (2014): NOAA Climate Data Record (CDR) of Leaf Area Index (LAI) and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR), Version 4. [indicate subset used]. NOAA National Climatic Data Center. doi:10.7289/V5M043BX

代码：

var dataset = ee.ImageCollection('NOAA/CDR/AVHRR/LAI_FAPAR/V4')
                  .filter(ee.Filter.date('2018-02-01', '2018-03-01'));
var leafAreaIndex = dataset.select('LAI');
var leafAreaIndexVis = {
  min: 0.0,
  max: 4000.0,
  palette: ['3b0200', '977705', 'ca9f06', 'ffca09', '006a03', '003b02'],
};
Map.setCenter(20, 24.5, 2);
Map.addLayer(leafAreaIndex, leafAreaIndexVis, 'Leaf Area Index');

代码：

var dataset = ee.ImageCollection('NOAA/CDR/AVHRR/LAI_FAPAR/V5')
                  .filter(ee.Filter.date('2018-02-01', '2018-03-01'));
var leafAreaIndex = dataset.select('LAI');
var leafAreaIndexVis = {
  min: 0.0,
  max: 4000.0,
  palette: ['3b0200', '977705', 'ca9f06', 'ffca09', '006a03', '003b02'],
};
Map.setCenter(20, 24.5, 2);
Map.addLayer(leafAreaIndex, leafAreaIndexVis, 'Leaf Area Index');