Elementary algorithms for determining the ocean dynamic topography from altimetric and gravity data

Rory Bingham*, Keith Haines, Chris Hughes

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference Contribution (Conference Proceeding)

1 Citation (Scopus)

Abstract

A key quantity in oceanography is the ocean's dynamic topography. While satellite altimetry has provided the oceanographic community with a good picture of the time variable dynamic topography for some time now, direct determination of the mean dynamic topography (MDT), which is simply the difference between the mean sea-surface and the geoid, has been restricted by the lack of a sufficiently accurate geoid. From an oceanography perspective the primary benefit from GOCE will be the resolution of this problem. However, because of the contrasting representations of the constituent surfaces, and their differing error characteristics, care is needed in the choice of algorithms used to derive the MDT. The objective of this paper is to assess a number of elementary approaches for computing and filtering the MDT. For the GOCE User Toolbox (GUT) determination of good elementary procedures is important since, compared with more sophisticated methods, such procedures are less computationally expensive, and are easier for a user to understand and implement. Two main computational algorithms are considered: conventional differencing of the mean sea-surface height and geoid height anomaly in the geographical domain, and differencing in the spectral domain. It is shown how the latter approach significantly reduces numerical artifacts in the resulting MDT. We also consider simple methods of filtering the MDT to remove noise. The problems of naive filtering, including coastal artifacts and the attenuation of oceanographic signals are considered, and methods to resolve these issues without incurring a high computational burden are presented.

Original languageEnglish
Title of host publicationProceedings of the 3rd International GOCE User Workshop
Pages269-276
Number of pages8
EditionSP-627
DOIs
Publication statusPublished - 1 Feb 2007
Event3rd International GOCE User Workshop - Frascati, Rome, Italy
Duration: 6 Nov 20068 Nov 2006

Conference

Conference3rd International GOCE User Workshop
CountryItaly
CityFrascati, Rome
Period6/11/068/11/06

Keywords

  • Dynamic topography
  • Geoid
  • Sea surface

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    Bingham, R., Haines, K., & Hughes, C. (2007). Elementary algorithms for determining the ocean dynamic topography from altimetric and gravity data. In Proceedings of the 3rd International GOCE User Workshop (SP-627 ed., pp. 269-276) https://doi.org/10.1109/RADECS.2003.185666