Testing the test: Accuracy assessment of gravity field models by independent satellite crossover altimetry, with examples for EIGEN 1S
Abstract
Success of accuracy assessments of the recent accurate gravity field models depends on quality, accuracy and reliability of the testing data, here the independent long-term averaged, single-satellite crossovers, corrected for many effects. With more accurate gravity models, we need a refinement of existing accuracy tests of these models. We present: (1) new linear transfer tests, (2) we test with the aid of the original SSC ERS 1/2 and Geosat data as well as with the latitude lumped coefficients (LLC). We work with EIGEN 1S tentatively scalled variance-covariance matrix (scaling factor of which is dependent on degree of harmonic geopotential coefficients), using this gravity model as an example of recent very accurate gravity models. But we also (3) descaled the covariance matrix and repeated the tests with the descaled one, checking the GFZ's scaling and seeking scaling factors "independently". (4) Thanks to encouraging results we can prepare a basis (linearly transferred SSC of ERS 1 and 2 from EIGEN 1S base) for testing of EIGEN 2 and forthcoming gravity models with more CHAMP and with new GRACE data. (5) As a by product of our analysis, we demonstrate that the NASA/GSFC Ocean Pathfinder correction for ionosphere needs an improvement.
- Publication:
-
EGS - AGU - EUG Joint Assembly
- Pub Date:
- April 2003
- Bibcode:
- 2003EAEJA.....2678W