CSR GRACE RL05 Mascon Solutions
Thank you for your interest in the latest, GRACE RL05 Mascon solutions from the Center for Space Research.
The data can be accessed in the NetCDF format at CSR_GRACE_RL05_Mascons_v01.nc
Data Span: April 2002 to June 2017
Data updated on: 2017-09-17
[Update 2017-10-24]: The Land and Ocean girds that accompany the CSR Mascon solutions (v01) are now available for download below in NetCDF format. Please consider these land and ocean masks when defining the basin masks in order to minimize leakage along the coastline.
CSR RL05 Mascons solutions: Acknowledgement and Citation
When using the CSR RL05 GRACE mascon solutions, please acknowledge that the data was downloaded from http://www.csr.utexas.edu/grace.
Save, H., S. Bettadpur, and B.D. Tapley (2016), High resolution CSR GRACE RL05 mascons, J. Geophys. Res. Solid Earth, 121, doi:10.1002/2016JB013007.
You can find the details about CSR RL05 Mascon solutions in the article above (click here to download). Please contact Himanshu Save (email@example.com) for more details.
Estimation resolution :
The data are represented on a ½ degree lon-lat grid, but they represent the equal-area geodesic grid of size 1x1 degree at the equator, which is the current native resolution of CSR RL05 mascon solutions.
Processing standards :
CSR RL05 GRACE Mascons are estimated with the same standards as the CSR RL05 Spherical harmonics solutions using GRACE Level-1 observations. Please visit the RL05 processing details page
C20 replacement :
The C20 (degree 2 order 0) coefficients are replaced with the C20 solutions from Satellite Laser Ranging [Cheng et al., 2013] for consistency with all the other GRACE solutions used in the Science community. The C20 time series from SLR is available at ftp://podaac.jpl.nasa.gov/allData/grace/docs/TN-07_C20_SLR.txt
Degree 1 Corrections :
The degree-1 coefficients (Geocenter) corrections are applied. These corrections are computed as trend and seasonal model to the degree-1 coefficients from Apr 2004 to Apr 2015 reported at GRACE Tellus (ftp://podaac.jpl.nasa.gov/allData/tellus/L2/degree_1/) using Swenson, Chambers, and Wahr (2008).
GIA Correction :
A glacial isostatic adjustment (GIA) correction has been applied based on the model from Geruo A and John Wahr (2013). The Spe ftp://podaac-ftp.jpl.nasa.gov/allData/tellus/L3/pgr/GIA_n100_mass_0km.txt
These mascon solutions are computed in presence of regularization constraint which is derived purely from GRACE information. No external model or data is used to inform the constraint matrix. Tikhonov regularization is used along with L-ribbon approach to compute the regularization parameter.
No empirical filtering :
No 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.
Anomaly baseline :
The GRACE anomalies reported in these mascon solutions are relative to a 2004.0000 - 2009.999 mean baseline.
Please note that while these solutions are estimated on a native resolution of about 120km wide cells, that is likely not the resolution of these GRACE solutions. The resolution of these solution is limited by the band-limited nature of GRACE. While we have not applied any implicit spatial smoothing, the users must exercise caution when using these solutions in basins smaller than approximately 200,000 km^2. Moreover, these solution should be used to perform basin level time-series analysis and never be used for analysis at a single grid point.
Rigorous uncertainty analysis for these solutions is still ongoing. In the meantime the users should use an uncertainty value of roughly 2cm. eq water height globally.
Geodesic grid used as a basis function to compute the mascon solution
Std dev. of the Ocean Bottom pressure signal computed from CSR GRACE RL05 mascons
Total water storage global trends from CSR GRACE RL05 mascons
Additional References and acknowledgements
Save, H., S. Bettadpur, and B. D. Tapley (2012), Reducing errors in the GRACE gravity solutions using regularization, J. Geod., doi:10.1007/s00190-012-0548-5
Cheng, M.K., B. D. Tapley, and J. C. Ries, "Deceleration in the Earth's oblateness", Jour. Geophys. Res., V118, 1-8, doi:10.1002/jgrb.50058, 2013
Swenson S.C , D. P. Chambers, and J. Wahr: Estimating geocenter variations from a combination of GRACE and ocean model output. J Geophys. Res.-Solid Earth, Vol 113, Issue: B8, Article B08410, . doi:10.1029/2007JB005338, 2008.
A, G., J. Wahr, and S. Zhong (2013) "Computations of the viscoelastic response of a 3-D compressible Earth to surface loading: an application to Glacial Isostatic Adjustment in Antarctica and Canada", Geophys. J. Int., 192, 557572, doi: 10.1093/gji/ggs030.
GIA model data and degree 1 coefficients were downloaded from http://grace.jpl.nasa.gov