||Validation of the temporal ocean mass variations from GRACE with in-situ observation
We validated the GRACE-derived temporal ocean mass variations with the two independent sets of in-situ observations. One set is the ocean mass variations at the TAO-TRITON moored-buoys. In this case, the ocean mass variations are obtained by subtracting the steric sea level changes estimated from the temperature profile measurements from the altimetric sea level changes. The other set is the ocean mass variations measured by the Bottom Pressure Recorders (BPRs) in the Deep-ocean Assessment and Reporting of Tsunamis (DART) array. Prior to the comparison, the degree-one Stokesí coefficients are estimated to minimize the GRACE-derived and in-situ variations in the least-square sense. After adjusting for the degree-one Stokesí component, we find that the ocean mass variations from GRACE correlate significantly with the in-situ mass variations. The influences of the degree-2 terms, which are subject to relatively large errors due to the orbit geometry, and of the difference of using different products (from CSR and GFZ) on the correlation will also be addressed.