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heimbach |
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Testing the Mid-depth Circulation in ECCO Ocean Estimates |
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Russ Davis (rdavis@ucsd.edu), Detlef Stammer (dstammer@ucsd.edu), |
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Scripps Institution of Oceanography |
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Tong Lee (tlee@pacific.jpl.nasa.gov) |
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Jet Propulsion Laboratory |
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Improved model physics, better surface forcing fields and higher numerical resolution |
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have made ocean circulation models more accurate. In addition, data assimilation has |
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improved the agreement of model simulations with observations and provides a rational |
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procedure for model testing using the very data that are assimilated as well as withheld |
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information. Most data used for assimilation are satellite altimetry and temperature |
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profiles from XBTs, P-ALACE and Argo that are most descriptive of the upper ocean. |
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In this study we use absolute mid-depth velocities from WOCE floats as independent |
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data to test the results from ECCO ocean circulation estimates at depths removed from |
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the majority of assimilated data. |
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The test will be performed at several stages of the assimilation: Comparisons of float |
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data with adjoint and Kalman-filter models having nominal resolution of 1o to 2o generally |
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show mean flows of generally similar shape but with the measured field being significantly |
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stronger. Some high-resolution simulations show zonal flows that cannot be identified in |
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the float data. Results from runs with and without insitu data will be used to identify |
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their impact on the estimated mean flow field. Although the float measurement density |
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is marginal for resolving variabili ty of narrow currents, comparisons with annual and |
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specific interannual variability is possible. |
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