Use of GOCE MDT and error information in Ocean Data Assimilation

The GOCE mission is producing gravity information of useful accuracy for ocean data assimilation. We use a GOCE based mean dynamic topography (MDT) along with an online bias correction scheme in order to correct remaining errors in the MDT particularly at shorter length scales. This bias correction is constrained within limits using the error information calculated along with the GOCE MDT. Sensitivity to these errors is also assessed. Results are presented from the Met Office assimilaiton system NEMOVAR, running the NEMO model at 1/4 degree global resolution. We investigate whether using the bias corrected GOCE MDT reduces the model forecast errors, compared to other MDT alternatives.