Mean Sea Surface and ocean circulation in North Atlantic and the Arctic Sea

High resolution Mean Sea Surface (MSS) model and its error estimation over the study region (56°

Steric sea level changes from ENVISAT and GRACE in the Nordic Seas

Steric sea level changes are estimated over the Nordic Seas using ENVISAT (Environmental Satellite) altimetry and GRACE (Gravity Recovery and Climate Experiment) gravity data. We have used altimetry data from the ENVISAT during October 2002 to October 2010, cycles 10 to 93, and the GRACE level 2 RL04 data released by GFZ (German Research Center for Geosciences) processing center during October 2002 to October 2010. It should be noted that some months are missing for the GRACE data set. Correction terms are applied to properly combine the altimetry and GRACE data, including the inverted barometer term, dynamic ocean and atmospheric terms and GRACE coefficients with degrees 0, 1, and 2 (with order 0). Finally, the steric sea level changes are derived over the Nordic Seas for October 2002 to October 2010

Updated OCTAS geoid in the northern North Atlantic - OCTAS07

A new gravimetric geoid (OCTAS07v2) is generated using Stokes’ formula with gravity data as input. As local gravity data, a combination of land gravity data, new and old airborne gravity data, and adjusted marine gravity data has been used. All marine gravity data has been error screened and quality assured by removing dubious data and adjusting the data when necessary. Voids in the gravity data distribution were patched with gravity data from satellite altimetry. The OCTAS07v2 geoid was estimated using the remove-compute-restore technique. The long-wavelength signal of the local gravity data was reduced using a Wong-Gore modified Stokes’ function. The long-wavelength part was represented by a global gravity field model based on GRACE data. The OCTAS07v2 geoid model was combined with the OCTAS07 MSS model to create a synthetic Mean Dynamic Topography (MDT) model. In comparison with the OCCAM MDT, our new synthetic MDT model gave a std. dev. of the residuals of 11 cm. A comparison to the main northern North Atlantic currents show many similar features