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Non-Tidal Non-Seasonal Oceanic Mass Redistribution Estimated from the TOPEX/Poseidon ObservationTopex/Poseidon altimetry data are used to estimate the non-tidal mass redistribution as a function of space-time. The goal is to study the contribution of ocean circulations in the geodynamic effects including Earth's rotational and gravitational variations. We examine the non-seasonal anomalies at monthly sampling rate over the T/P span of eight years, concentrating especially on interannual variabilities. Since the sea-surface height data obtained from altimetry is the combined effect of steric change (primarily thermal effect) and the mass flux, and because the former has zero contribution to the geodynamic effects, one needs to do a so-called steric correction by removing from the altimetry data the steric contributions. We achieve it using multiyear monthly sea-surface temperature maps, together with monthly "climatology" for mixed-layer depth maps for mean-months of the year. We analyze both sets of the altimetry data and the steric correction data using the empirical orthogonal function/principal component analysis (in which we take care of issues associated with the area-weighting and non-zero mean), and examine the most important modes, either globally or regionally. In particular, the ENSO in the tropical Pacific/Indian Oceans exhibits the most prominent pattern. The net mass transport after the steric correction can then be compared with: (1) ocean general circulation model outputs for the same period of time (such as from POCM-4B); (2) non-atmospheric Earth rotation variations obtained from space geodesy data and atmospheric angular momentum data; (3) non-atmospheric low-degree gravitational variations from satellite-laser-ranging observations and global atmospheric data.
Document ID
20010115968
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Chao, Benjamin F.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Au, A. Y.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Chen, Jian-Li
(Texas Univ. Austin, TX United States)
Smith, David E.
Date Acquired
August 20, 2013
Publication Date
January 1, 2000
Subject Category
Oceanography
Meeting Information
Meeting: Joint TOPEX/Poseidon and JASON-1 Science Working Team Meeting
Location: Miami Beach, FL
Country: United States
Start Date: November 15, 2000
End Date: November 17, 2000
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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