The images were generated from the monthly ocean mass grids, which contain ocean water mass given as equivalent water thickness derived from the Center of Space Research (CSR) GRACE ocean bottom pressure with an Empirical Orthogonal Function (EOF) applied. Equivalent water thickness is used to represent the water mass so it can be comparable to sea level anomalies due to water mass changes. There are several different types of Gaussian smoothing (300-750 km radius) and image resolutions. The time coverage for the monthly grids are determined by GRACE months. For the list of GRACE month dates visit http://grace.jpl.nasa.gov/data/grace-months/. For information please visit http://grace.jpl.nasa.gov/data/get-data/monthly-mass-grids-ocean/.