GRACE Tellus Monthly Mass Grids provides monthly gravitational anomalies relative to a 2004-2010 time-mean baseline. The data contained in this dataset are units of "Equivalent Water Thickness" which represent the deviations of mass in terms of vertical extent of water in centimeters. See the provider's Monthly Mass Grids Overview for more details.
The GRACE Tellus (GRCTellus) Monthly Mass Grids dataset is produced by three centers: CSR (U. Texas / Center for Space Research), GFZ (GeoForschungsZentrum Potsdam), and JPL (NASA Jet Propulsion Laboratory). Each center is a part of the GRACE Ground System and generates Level-2 data (spherical harmonic fields) used in this dataset. The output includes spherical harmonic coefficients of the gravity field and of the dealiasing fields used to compute them. Since each center independently produces the coefficients, the results may be slightly different. It is recommended for most users to use the mean of all three datasets. See the provider's choosing a solution page for more details.
Note
- Due to the sampling and post-processing of GRACE observations, surface mass variations at small spatial scales tend to be attenuated. Therefore, users should multiply the GRCTellus Land data by the scaling grid available at NASA/GRACE/MASS_GRIDS/LAND_AUX_2014.
- The GRCTellus Land grids processed from the Spherical Harmonic Level-2 data are not suited to accurately quantify ice mass changes over Greenland or Antarctica, or glaciers and ice caps. For those areas it is recommended to use JPL's mascon solution available as the following image collection: NASA/GRACE/MASS_GRIDS/MASCON
GRACE Tellus月度质量网格提供了相对于2004-2010年时间平均基线的月度引力异常值。该数据集所包含的数据是以 "等水厚度 "为单位，以厘米为单位表示水的垂直范围的质量偏差。更多细节请参见提供者的月度质量网格概述。
GRACE Tellus（GRCTellus）月度质量网格数据集由三个中心制作。CSR（德克萨斯大学/空间研究中心）、GFZ（波茨坦地质研究中心）和JPL（美国航空航天局喷气推进实验室）。每个中心都是GRACE地面系统的一部分，并产生本数据集所使用的二级数据（球面谐波场）。输出包括重力场和用于计算它们的纠偏场的球面谐波系数。由于每个中心独立产生系数，结果可能略有不同。对大多数用户来说，建议使用所有三个数据集的平均值。更多的细节请见供应商的选择解决方案页面。
注意
由于GRACE观测的采样和后处理，小空间尺度的表面质量变化往往被削弱。因此，用户应将GRCTellus陆地数据乘以NASA/GRACE/MASS_GRIDS/LAND_AUX_2014上的比例网格。
由球面谐波Level-2数据处理的GRCTellus陆地网格不适合准确量化格陵兰岛或南极洲、冰川和冰盖的冰量变化。对于这些地区，建议使用JPL的mascon解决方案，可作为以下图片集。nasa/grace/mass_grids/mascon
Dataset Availability
2002-04-01T00:00:00 - 2017-02-03T00:00:00
Dataset Provider
NASA Jet Propulsion Laboratory
Collection Snippet
ee.ImageCollection("NASA/GRACE/MASS_GRIDS/LAND")
Resolution
111320 meters
Bands Table
Name | Description | Min* | Max* | Units |
|---|---|---|---|---|
lwe_thickness_csr | Equivalent liquid water thickness in centimeters calculated by CSR. | -139.2 | 74.88 | cm |
lwe_thickness_gfz | Equivalent liquid water thickness in centimeters calculated by GFZ. | -145.45 | 70.19 | cm |
lwe_thickness_jpl | Equivalent liquid water thickness in centimeters calculated by JPL. | -137.94 | 71.86 | cm |
* = Values are estimated
影像属性：
Name | Type | Description |
|---|---|---|
CSR_END_TIME | Double | End date in milliseconds of spherical harmonics solution from CSR. |
CSR_START_TIME | Double | Start date in milliseconds of spherical harmonics solution from CSR. |
GFZ_END_TIME | Double | End date in milliseconds of spherical harmonics solution from GFZ. |
GFZ_START_TIME | Double | Start date in milliseconds of spherical harmonics solution from GFZ. |
JPL_END_TIME | Double | End date in milliseconds of spherical harmonics solution from JPL. |
JPL_START_TIME | Double | Start date in milliseconds of spherical harmonics solution from JPL. |
使用说明：
All NASA-produced data from the GRACE mission is made freely available for the public to use. When using any of the GRCTellus data, please add an acknowledgment: "GRACE land are available at https://grace.jpl.nasa.gov, supported by the NASA MEaSUREs Program." and cite with the citations provided.
引用：
S.C. Swenson. 2012. GRACE monthly land water mass grids NETCDF RELEASE 5.0. Ver. 5.0. PO.DAAC, CA, USA. Dataset accessed [YYYY-MM-DD] at https://doi.org/10.5067/TELND-NC005.
Landerer F.W. and S. C. Swenson, Accuracy of scaled GRACE terrestrial water storage estimates. Water Resources Research, Vol 48, W04531, 11 PP, doi:10.1029/2011WR011453, 2012.
Swenson, S. C. and J. Wahr, Post-processing removal of correlated errors in GRACE data, Geophys. Res. Lett., 33, L08402, doi:10.1029/2005GL025285, 2006.
代码：
代码语言：javascript复制var dataset = ee.ImageCollection('NASA/GRACE/MASS_GRIDS/LAND')
.filter(ee.Filter.date('2016-08-01', '2016-08-30'));
var equivalentWaterThicknessCsr = dataset.select('lwe_thickness_csr');
var equivalentWaterThicknessCsrVis = {
min: -25.0,
max: 25.0,
};
Map.setCenter(6.746, 46.529, 2);
Map.addLayer(
equivalentWaterThicknessCsr, equivalentWaterThicknessCsrVis,
'Equivalent Water Thickness CSR');
