ITU_GRACE16 is a static global gravity field model up to degree order 180 computed from GRACE SST data of 50 months collected between April 2009 to October 2013 by collaboration of various national institutions (YTU, KOU, NEU, SU) lead by ITU and OSU as the international collaborator with the support of research grant no 113Y155 from the Scientific and Technological Research council of Turkey (TUBITAK). The model coefficients are obtained following a two-step approach. (1) the in-situ geopotential differences (GPDs) between GRACE satellite are estimated using SST and precise orbit using improved energy integral method given in Guo et al. 2015 and Shang et al. 2015. (2) The estimated GPDs were then used as the observables of the SH expansion for the inversion.ITU_GRACE16 is not regularized or constrained in any way, the errors increase with degree. We do not recommend to use ITU_GRACE16 beyond the degree 130 without smoothing. No rate terms were modeled, and no corrections for earthquakes have been applied. For additional details on the background modeling,see the GFZ RL05 processing standards document available at:

Input Data:- GRACE RL02 L1B (JPL) data products: 50 months Apr 2009 – Oct 2013- AOD1B RL05 (GFZ) idealising product- GIF48 static field as the background gravity field model (only up to d/o 180)