NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Combination of TOPEX/POSEIDON Data with a Hydrographic Inversion for Determination of the Oceanic General Circulation and its Relation to Geoid AccuracyA global estimate of the absolute oceanic general circulation from a geostrophic inversion of in situ hydrographic data is tested against and then combined with an estimate obtained from TOPEX/POSEIDON altimetric data and a geoid model computed using the JGM-3 gravity-field solution. Within the quantitative uncertainties of both the hydrographic inversion and the geoid estimate, the two estimates derived by very different methods are consistent. When the in situ inversion is combined with the altimetry/geoid scheme using a recursive inverse procedure, a new solution, fully consistent with both hydrography and altimetry, is found. There is, however, little reduction in the uncertainties of the calculated ocean circulation and its mass and heat fluxes because the best available geoid estimate remains noisy relative to the purely oceanographic inferences. The conclusion drawn from this is that the comparatively large errors present in the existing geoid models now limit the ability of satellite altimeter data to improve directly the general ocean circulation models derived from in situ measurements. Because improvements in the geoid could be realized through a dedicated spaceborne gravity recovery mission, the impact of hypothetical much better, future geoid estimates on the circulation uncertainty is also quantified, showing significant hypothetical reductions in the uncertainties of oceanic transport calculations. Full ocean general circulation models could better exploit both existing oceanographic data and future gravity-mission data, but their present use is severely limited by the inability to quantify their error budgets.
Document ID
19970022305
Acquisition Source
Jet Propulsion Laboratory
Document Type
Reprint (Version printed in journal)
Authors
Ganachaud, Alexandre
(Massachusetts Inst. of Tech. Cambridge, MA United States)
Wunsch, Carl
(Massachusetts Inst. of Tech. Cambridge, MA United States)
Kim, Myung-Chan
(Texas Univ. Austin, TX United States)
Tapley, Byron
(Texas Univ. Austin, TX United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1997
Publication Information
Publication: Geophysical Journal International
Volume: 128
Subject Category
Oceanography
Report/Patent Number
NAS 1.26:204735
NASA-CR-204735
Accession Number
97N22876
Funding Number(s)
CONTRACT_GRANT: JPL-958125
CONTRACT_GRANT: NAGw-918
Distribution Limits
Public
Copyright
Public Use Permitted.
No Preview Available