The monthly mass grids provided here contain global water storage anomalies relative to a time-mean as derived from GRACE time-variable gravity data. This dataset provides mass anomalies for ocean, ice, and hydrology with a clean separation of mass along coastlines. The storage anomalies are given in equivalent water thickness units (in NetCDF format). The solution provided here is derived from solving for monthly gravity field variations in terms of spherical cap mass concentration functions, rather than spherical harmonic coefficients. Additionally, realistic geophysical information is introduced during the solution inversion to intrinsically remove correlated error. Thus, these mascon solutions do not need to be destriped or smoothed, like traditional spherical harmonic gravity solutions. The mascon solution consists of 4,551 relatively independent estimates of surface mass change (we solve for equal-area 3-degree mascons). A subset of these mascons span coastlines, and contain mixed land and ocean mass change signals. In a post-processing step, we have applied a Coastline Resolution Improvement (CRI) filter to the mascon solution to separate land and ocean mass from these mascons that span coastlines. The land mask used to perform this separation can be found within the same data directory as the mascon data. Since the mascons themselves act on an inherent smoother on the gravity field, a set of optional gain factors that can be applied to the solution to study mass change signals at sub-mascon resolution is also provided within the same data directory as the mascon data. Please refer to the 'Data Access' tab at the top of this page to gain direct access to the mascon data. For more information, please visit http://grace.jpl.nasa.gov/data/get-data/jpl_global_mascons/. For a detailed description on the mascon solution, including the mathematical derivation, implementation of geophysical constraints, and solution validation, please see Watkins et al., 2015, doi: 10.1002/2014JB011547.