Google Earth Engine（GEE）——GEDI L4B全球地表生物量密度1000m分辨率数据集

GEDI L4B Gridded Aboveground Biomass Density (Version 2)

这个全球生态系统动态调查（GEDI）L4B产品提供了基于从2019-04-18开始的第19任务周到2021-08-04结束的第138任务周的观测结果的1公里×1公里平均地上生物量密度（AGBD）的估计值。GEDI L4A足迹生物量产品将每个高质量的波形转换为AGBD预测，而L4B产品使用每个1公里单元边界内存在的样本来统计推断平均AGBD。

GEDI L2A矢量数据可以在表集LARSE/GEDI/GEDI02_A_002中找到。

GEDI L2A月度栅格数据可以在图像集LARSE/GEDI/GEDI02_A_002_MONTHLY中找到。

更多信息请见用户指南。

Dataset Availability

2019-04-18T00:00:00Z - 2021-08-04T00:00:00

Dataset Provider

​​USFS Laboratory for Applications of Remote Sensing in Ecology (LARSE) ​​​​NASA GEDI mission, accessed through the USGS LP DAAC​​

Earth Engine Snippet

​

​ee.Image("LARSE/GEDI/GEDI04_B_002")​

​

Resolution

1000 meters

Bands

Name	Units	Description
​ ​MU​ ​	Mg ha^-1	Mean aboveground biomass density (MU): Estimated mean AGBD for the 1 km grid cell, including forest and non-forest.
​ ​V1​ ​	Variance component 1 (V1): Uncertainty in the estimate of mean biomass due to the field-to-GEDI model used in L4A.
​ ​V2​ ​	Variance component 2 (V2) If Mode of Inference = 1, this is the uncertainty due to GEDI's sampling of the 1 km cell. If Mode of Inference = 2, this is uncertainty owing to the model predicting biomass using wall-to-wall data, calibrated with the L4A footprint product.
​ ​SE​ ​	Mg ha^-1	Mean aboveground biomass density standard error (SE): Standard Error of the mean estimate, combining sampling and modeling uncertainty.
​ ​PE​ ​	Percent	Standard error as a fraction of the estimated mean AGBD (PE). If >100%, the cell values are truncated to 100.
​ ​NC​ ​	Number of clusters (NC): Number of unique GEDI ground tracks with at least one high-quality waveform intersecting the grid cell.
​ ​NS​ ​	Number of samples (NS): Total number of high-quality waveforms across all ground tracks within the grid cell.
​ ​QF​ ​	Quality flag (QF) 0=Outside the GEDI domain 1=Land surface 2=Land surface and meets GEDI mission L1 requirement (Percent standard error <20% or Standard Error < 20 Mg ha-1)
​ ​PS​ ​	Prediction stratum (PS) determined by plant functional type and continent. PS is associated with an L4A model parameter covariance matrix that contributes to the Model Error Variance (Table 2).
​ ​MI​ ​	Mode of interference (MI): Method used for a particular cell. Until mission completion, only those cells where hybrid inference is possible will be populated with a mean biomass value. 0=None applied 1=Hybrid Model-Based 2=Generalized Hierarchical Model-Based

代码：

var l4b = ee.Image('LARSE/GEDI/GEDI04_B_002')

Map.addLayer(
    l4b.select('MU'),
    {min: 10, max: 250, palette: '440154,414387,2a788e,23a884,7ad151,fde725'},
    'Mean Biomass');
Map.addLayer(
    l4b.select('SE'),
    {min: 10, max: 50, palette: '000004,3b0f6f,8c2981,dd4a69,fe9f6d,fcfdbf'},
    'Standard Error');      

Citations:

• Dubayah, R.O., J. Armston, S.P. Healey, Z. Yang, P.L. Patterson, S. Saarela, G. Stahl, L. Duncanson, and J.R. Kellner. 2022. GEDI L4B Gridded Aboveground Biomass Density, Version 2. ORNL DAAC, Oak Ridge, Tennessee, USA. ​​doi:10.3334/ORNLDAAC/2017​​
• ​​GEDI L4B Gridded Aboveground Biomass Density, Version 2, https://doi.org/10.3334/ORNLDAAC/2017​​

 标准差：

 平均生物量：