Sixth Conference on Coastal Atmospheric and Oceanic Prediction and Processe

Chu, Peter C.

Ivanov, Leonid

Melnichenko, Oleg

Calhoun, Institutional Archive of the Naval Postgraduate School

Calhoun: The NPS Institutional ArchiveFaculty and Researcher Publications Faculty and Researcher Publications2005Prediction of synoptic current reversalson the Louisiana-Texas continental shelfIvanov, LeonidChu, P.C., L.M. Ivanov, and O. V. Melnichenko, Prediction of synoptic current reversals on theLouisiana-Texas continental shelf. Sixth Conference on Coastal Atmospheric and OceanicPrediction and Processes, American Meteorological Society, San Diego, California, 9-13January 2005 (download).http://hdl.handle.net/10945/36539Prediction of Synoptic Current Reversals on the Texas-Louisiana Continental ShelfPeter C Chu, Leonid Ivanov, Oleg MelnichenkoNaval Postgraduate SchoolMonterey, CA 93943pcchu@nps.eduhttp://www.oc.nps.navy.mil/~chuReference Chu, P.C., L.M. Ivanov, and O.V. Melnichenko, 2004: Fall-winter current reversals on the Taxes-Lousianacontinental shelf, Journal of Physical Oceanography, in press.Ocean Velocity Data  31 near-surface (10-14 m) current meter moorings during LATEX from April 1992 to November 1994  Drifting buoys deployed at the first segment of the Surface Current and Lagrangian-drift Program (SCULP-I) from October 1993 to July 1994.Surface Wind Data 7 buoys of the National Data Buoy Center (NDBC) and industry (C-MAN) around LATEX areaMoorings  and Buoys Flow DecompositionOptimal Spectral DecompositionReferences  Chu, P.C., L.M. Ivanov, T.P. Korzhova, T.M. Margolina, and O.M. Melnichenko, 2003a: Analysis of sparse and noisy ocean current data using flow decomposition. Part 1: Theory. Journal of Atmospheric and Oceanic Technology, 20 (4), 478-491.  Chu, P.C., L.M. Ivanov, T.P. Korzhova, T.M. Margolina, and O.M. Melnichenko, 2003b: Analysis of sparse and noisy ocean current data using flow decomposition. Part 2: Application to Eulerian and Lagrangian data. Journal of Atmospheric and Oceanic Technology, 20 (4), 492-512.  Chu, P.C., L.M. Ivanov, and T.M. Margolina, 2004: Rotation method for reconstructing process and field from imperfect data. International Journal of Bifurcation and Chaos, in press.Reconstructed and observed circulations at Station-24. TLCS current reversal detected from SCULP-I drift trajectories. TLCS current reversal detected from the reconstructed velocity dataDecember 30, 1993January 3, 1994January 6, 1994Probability of TLCS Current Reversal for Given Period (T)  n0 ~0-current reversal  n1~ 1-current reversal n2~ 2-current reversals m ~ all realizationsFitting the Poison Distributionµ is the mean number of reversal for a single time intervalµ ~ 0.08Dependence of P0, P1, P2 on TFor observational periods larger than 20 days,  the probability for no currentreversal is less than 0.2. For 15 day observational period, the probability for 1-reversal reaches 0.5Data – Solid CurvePoison Distribution Fitting –Dashed CurveTime Interval between Successive Current Reversals (not a Rare Event)EOF Analysis of the Reconstructed Velocity Filed0.81.10.762.31.41.154.63.31.446.95.63.939.39.510.1274.477.180.2110/05/94-11/29/9412/19/93-04/17/9401/21/93-05/21/93Variance (%)EOFMean and First EOF ModeMean Circulation1. First Period (01/21-05/21/93)2. Second Period   12/19/93-04/17/94)3. Third Period (10/05-11/29/94)EOF11. First Period (01/21-05/21/93)2. Second Period   12/19/93-04/17/94)3. Third Period (10/05-11/29/94) Calculated A1(t) Using Current Meter Mooring (solid)and SCULP-1Drifters (dashed) 8 total reversals observed  Uals ~ alongshore windMorlet Wavelet A1(t) Uals Regression between A1(t) and Surface  Winds  Solid Curve (reconstructed) Dashed Curve (predicted using winds)Conclusions Alongshore wind forcing is the major factor causing the synoptic current reversal.  Other factors, such as the Mississippi-Atchafalaya River discharge and offshore eddies of Loop Current origin, may affect the reversal threshold, but can not cause the synoptic current reversal. 

Prediction of synoptic current reversals on the Louisiana-Texas continental shelf

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Prediction of synoptic current reversals on the Louisiana-Texas continental shelf

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