一直有粉絲詢問我數(shù)據(jù)下載的問題，這里我將匯總?cè)驡RACE Mascon數(shù)據(jù)的下載鏈接，以及基礎的數(shù)據(jù)處理方法。

首先，GRACE Mascon數(shù)據(jù)包含有三大機構(gòu)，分別是CSR、JPL和GSFC（注意不是GFZ）。

1.CSR mascon

下載網(wǎng)址：https://www2.csr.utexas.edu/grace/RL06_mascons.html

數(shù)據(jù)的基本信息：①The solutions with all the appropriate corrections applied (GAD, GIA, C20, C30, degree1, etc) in equi-angular grids.【前期數(shù)據(jù)預處理已經(jīng)完成】

②The mass anomaly grids in CSR RL06 v02 mascons for the GRACE/GRACE-FO time variable gravity are represented on the ellipsoidal earth of semi-major axis of 6378.1363 km

③已經(jīng)完成的預處理：C20 replacement ，C30 replacement ，Degree 1 Corrections，GIA Correction ，GAD Correction

④Please note that all the grids provided (including the corrected grids) are anomalies relative to 2004.0000 - 2009.999 mean baseline.?If any user decides to undo any correction and apply their own corrections, they should compute the anomalies relative to the same mean baseline for their corrections before applying their corrections.

⑤No additional smoothing or empirical de-striping or filtering applied to this data. The users should not apply any additional filtering or scaling factors to these solutions. These global solutions are not tailored towards a particular application and hence the solution set is applicable to all science areas of interest ie., oceanography, land surface hydrology, cryosphere, etc.

2.JPL Mascon

下載網(wǎng)址：https://grace.jpl.nasa.gov/data/get-data/jpl_global_mascons/

數(shù)據(jù)的基本信息：①基于Level-1 GRACE/GRACE-FO observations數(shù)據(jù)解算

②進行了一階項補充、二階項替換、GIA改正【ICE6G-D model from Peltier et al. (2017)】

③No additional empirical destriping filter has been applied to the data. This results in better S/N ratios of the mascon fields compared to the conventional spherical-harmonic solutions.【未進行前期的濾波處理，采用先驗的質(zhì)量劃分，得到比GRACE球諧數(shù)據(jù)更高的信噪比】

④All reported data are?anomalies relative to the 2004.0-2009.999 time-mean baseline. Note that this baseline needs to be consistent when comparing GRACE/GRACE-FO data to other anomaly data (e.g., groundwater or sea level).?

⑤Note that the land-grid-scaling (described below) has?not?yet?been applied to the GRACE/GRACE-FO data fields; users must apply these optional gain factors. 【需要進行尺度因子恢復原始信號】

⑥Please note: the gain factors can be used for hydrology-related signals, but should not be used for mountain glaciers or ice sheets【不用于山地冰川冰蓋的質(zhì)量信號恢復，as these components are not in the CLM data that is underlying（水文模型的低估） the gain factors】，尺度因子計算：g'(x,y,t) = g(x,y,t) * s(x,y)

3.GSFC Mascon

下載網(wǎng)址：https://earth.gsfc.nasa.gov/geo/data/grace-mascons

數(shù)據(jù)基本信息：①GSFC.glb.200204_202211_RL06v2.0_OBP-ICE6GD，Global mascon solution where the GAD product has been restored, meaning the ocean mascons describe ocean bottom pressure (OBP). This product is comparable to the JPL and CSR mascon products.

②GSFC.glb.200204_202211_RL06v2.0_OBP-ICE6GD_HALFDEGREE.nc，Global mascon solution where the GAD product has been restored, meaning the ocean mascons describe ocean bottom pressure (OBP). This product is comparable to the JPL and CSR mascon products. The 1-arc-degree equal area values have been placed on an equal angle 0.5x0.5 degree grid. Land values are determined with a least squares estimator that conserves mass over each region, while ocean values have been interpolated/extrapolated.【建議下載這個】

③Mean removed: 2004.0 – 2010.0，與CSR和JPL的時間段一致

④同樣進行了一階項補充、二階項替換、C30替換、GIA改正

關于讀取時間序列，可以去我的CSDN下載一個程序包：https://download.csdn.net/download/weixin_43047707/85401807?spm=1001.2014.3001.5503，里面包含讀取格網(wǎng)數(shù)據(jù)的程序，其對于三大機構(gòu)的數(shù)據(jù)都適用

另外，我還發(fā)現(xiàn)一個很有用的網(wǎng)站，可以在線分析全球流域的水儲量變化【看來用GRACE單純做流域水儲量變化已經(jīng)做爛了，沒意義。。?！?br>

網(wǎng)址：https://ccar.colorado.edu/grace/index.html，如下的界面，可以選擇GSFC和JPL的mascon的數(shù)據(jù)。

選擇GSFC數(shù)據(jù)，進入界面，可以選擇大洲和流域，以及全球的趨勢。我們這里選擇流域

選擇長江流域，點擊界面，即可以看到長江流域的所有的質(zhì)量變化時間序列，還可以選擇質(zhì)量變化（Gt）和等效水高變化（cm），同時可以選擇導出數(shù)據(jù)?！镜潜救擞X得用于計算結(jié)果的參考還行，用于論文數(shù)據(jù)結(jié)果欠妥】

下面是全球的質(zhì)量變化速率圖

歡迎點贊收藏?。?/p>