The JPL GRACE Mascon Ocean, Ice and Hydrology Equivalent Water Height (hereafter, Mascon) Version 2 datasets have been recently updated with four additional months to its data time series, which brings the time series up to June, 2017. Users are cautioned that after August 2016, the accelerometer on GRACE-B has been turned off, and an “accelerometer transplant” product (from GRACE-A) has been used in its place. The month of May 2017 is an exception to this, as both accelerometers were collecting data for this month. The use of an accelerometer transplant product has resulted in additional uncertainty in the surface mass fields starting in November 2016. The uncertainty values that accommodate the solution in the netCDF files have increased correspondingly.
Access to the CRI dataset, valued for its Coastline Resolution Improvement (CRI) filter to separate land and ocean mass anomalies along coastlines, can be found here: https://podaac.jpl.nasa.gov/dataset/TELLUS_GRACE_MASCON_CRI_GRID_RL05_V2
Expert users who wish to access the data without the implementation of the CRI filter can find the non-CRI dataset here: https://podaac.jpl.nasa.gov/dataset/TELLUS_GRACE_MASCON_GRID_RL05_V2
Data will continue to be updated with a nominal 2-4 month latency.
As an artifact of the JPL Mascon Version 2 processing algorithm, the integration of the additional four months of data have resulted in very slight changes to data from all previous months. Users who wish to continue accessing data from previous months under previous Version 2 iterations can do so by visiting the following FTP location: ftp://podaac.jpl.nasa.gov/allData/tellus/retired/L3/mascon/RL05/JPL/
For more general information about the Mascon processing, usage guidance, and information on auxiliary files, please visit http://grace.jpl.nasa.gov/data/get-data/jpl_global_mascons/.
For a detailed description on the Mascon algorithm, including the mathematical derivation, implementation of geophysical constraints, and solution validation, please see Watkins et al., 2015, DOI: 10.1002/2014JB011547.