Abstract: CATS2008 is a regional inverse barotropic tide model for the circum-Antarctic ocean on a 4 km grid. The model domain includes ocean cavities under the floating ice shelves. The coastline is based on the MODIS MOA [Scambos et al., 2007; Remote Sensing of Environment] feature identification files, adjusted to match ICESat-derived grounding lines for the Ross and Filchner-Ronne ice shelves and Interferometric Synthetic Aperture Radar (InSAR) grounding lines. The water depth map for open water is based on the 2007 release update to Smith and Sandwell [1997; Science]. Adjustments to this map have been made in various regions, including the open continental shelf in front of the Larsen-C Ice Shelf which has been blended with GEBCO bathymetry. Model type: Tides only; Inverse (data assimilation); barotropic (no vertical variation of currents) Grid: 4-km uniform polar stereographic (centered at 71 degrees S, 70 degrees W) Constituents: M2, S2, N2, K2, K1, O1, P1, Q1, Mf, Mm Units: z (sea surface height; meters); u,v (currents; cm/s); U,V (transports; m2/s) Coordinates: Currents (u, v) and depth-integrated transports (U, V) are given as East (u, U) and North (v, V) components Citation: “… an update to the inverse model described by Padman et al. [2002].” See CATS2008_README.pdf for further details.