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：