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Improving ocean angular momentum estimates using a model constrained by data
Author(s) -
Ponte Rui M.,
Stammer Detlef,
Wunsch Carl
Publication year - 2001
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2000gl011671
Subject(s) - angular momentum , rotation (mathematics) , context (archaeology) , earth's rotation , ocean current , consistency (knowledge bases) , geodesy , physics , momentum (technical analysis) , geology , meteorology , classical mechanics , climatology , mathematics , geometry , paleontology , finance , economics
Ocean angular momentum (OAM) calculations using forward model runs without any data constraints have recently revealed the effects of OAM variability on the Earth's rotation. Here we use an ocean model and its adjoint to estimate OAM values by constraining the model to available oceanic data. The optimization procedure yields substantial changes in OAM, related to adjustments in both motion and mass fields, as well as in the wind stress torques acting on the ocean. Constrained and unconstrained OAM values are discussed in the context of closing the planet's angular momentum budget. The estimation procedure yields noticeable improvements in the agreement with the observed Earth rotation parameters, particularly at the seasonal timescale. The comparison with Earth rotation measurements provides an independent consistency check on the estimated ocean state and underlines the importance of ocean state estimation for quantitative studies of the variable large‐scale oceanic mass and circulation fields, including studies of OAM.