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Atmospheric densities from ESA's GOCE satellite at a mean altitude of 270 km are validated by comparison with predictions from the near real time model HASDM along the GOCE orbit in the time frame 1 November 2009 through 31 May 2012. Except for a scale factor of 1.29, which is due to different aerodynamic models being used in HASDM and GOCE, the agreement is at the 3% (standard deviation) level when comparing daily averages. The models NRLMSISE-00, JB2008 and DTM2012 are compared with the GOCE data. They match at the 10% level, but significant latitude-dependent errors as well as errors with semiannual periodicity are detected. Using the 0.1 Hz sampled data leads to much larger differences locally, and this dataset can be used presently to analyze variations down to scales as small as 150 km. [ABSTRACT FROM AUTHOR]

In the framework of the ESA High Processing Facility (HPF), eight gravity models have been computed from the GOCE data since the beginning of the mission in 2009. The accuracy of these models for oceanographic application is assessed and compared with other geoid models (i.e., ITG-GRACE 2010S, EGM2008, EIGEN6C). For that purpose, ocean Mean Dynamic Topography (MDT) estimates are computed by subtracting the different geoids from an altimetric Mean Sea Surface. The MDT assessments were carried out by analyzing their associated geostrophic surface currents at different maximum harmonic degrees and by comparing them with independent in situ oceanographic data. Compared with GRACE-only geoid models, GOCE-only geoid models are in better agreement with independent data at scales smaller than 150 km while they show similar performances at scales larger than 200 km. Regional comparisons show that at 125 km the HPF releases compare well to independent observations with significant improvement with the last releases that use more GOCE data. At 100 km the western boundary currents are well resolved by the last releases, but the satellite-only geoid models need to be further improved to resolve smaller scales and reach the targeted 100 km resolution with higher accuracy. [ABSTRACT FROM AUTHOR]