GGM05C is an unconstrained global gravity model complete to degree and order 360 determined from 1) GRACE K-band intersatellite range-rate data, GPS tracking and GRACE accelerometer data, 2) GOCE gradiometer data (ZZ+YY+XX+XZ) spanning the entire mission using a band pass filter of 10-50 mHz and polar gap filled with synthetic gradients from GGM05S to degree/order 150 evaluated at 200-km altitude, and 3) terrestrial gravity anomalies from DTU13 (Andersen et al., 2014). The value for C20 has been replaced with a value derived from satellite laser ranging. No rate terms were modeled.
For additional details on the background modeling, see the CSR RL05 processing standards document available at ftp://podaac.jpl.nasa.gov/allData/grace/docs/L2-CSR0005_ProcStd_v4.0.pdf (Bettadpur 2012). Detailed information about GGM05C is available at ftp://ftp.csr.utexas.edu/pub/grace/GGM05/README_GGM05C.pdf (Ries et al., 2016).