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Xiaochun Wang

Influence of Stratification on Semidiurnal Tides in Monterey Bay, California & Coastal Barotropic Tide Solutions. a b. Xiaochun Wang. . Validation of tidal solution . Influence of stratification. Contributions from: JPL Yi Chao

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Xiaochun Wang

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  1. Influence of Stratification on Semidiurnal Tides in Monterey Bay, California & Coastal Barotropic Tide Solutions a b Xiaochun Wang . Validation of tidal solution . Influence of stratification Contributions from: JPL Yi Chao OSU C.K. Shum, Yuchan Yi UCLA Changming Dong, James McWillams NPS Leslie Rosenfeld, Jeffery Paduan NAO Koji Matsumoto, Tadahiro Sato Newcastle Xiaoli Deng; Hong Kong PolyTech Baki Iz OSTST 2006 a: Jet Propulsion Lab/California Institute of Technology b: Raytheon, ITSS

  2. Comparison with TOPEX Barotropic Tide cm Away from the coast Tidal BC from TPXO6.0 Root of Summed Square 3.45cm <6% of M2 amplitude

  3. Baroclinic Tides Derived from Altimetry and ROMS cm cm Satellite Sample # Mean Amp Std Amp Corr (Amp) Corr (Pha) TOPEX 1013 0.52 0.30 0.195 0.103 T/P-Tandem 1070 0.76 0.41 0.009 0.072 GFO 1855 0.81 0.46 0.1010.087 ROMS 1013 0.25 0.15 1.000 1.000 Significant at 99% level by Monte Carlo simulation. * Cycles used, TOPEX: 4-364, Tandem: 369-479, GFO: 37-168 Envisat: ~250 data points.

  4. Baroclinic Tides Derived from Altimetry TOPEX T/P-Tandem GFO TOPEX 1.0 0.124 0.351 T/P-Tandem 84.3% 1.0 0.298 GFO 99.2% 99.5% 1.0 Amplitude TOPEX T/P-Tandem GFO TOPEX 1.0 0.157 0.206 T/P-Tandem 90.3% 1.0 0.079 GFO 99.6% 85.1% 1.0 Phase Correlation coefficients and their significant level, 99% highlighted.

  5. Surface Tidal Currents with Different Stratification Tidal Current Improved Experiment 1: Levitus climatology + Hourly forcing Experiment 2 1-year spin-up run from Levitus climatology + Hourly forcing Experiment 3 Data-assimilated initial condition of August 2003 + Hourly forcing Experiment 4 Data-assimilated initial condition of Aug. 2003 + Monthly forcing

  6. Barotropic and Surface Baroclinic Tidal Currents Barotropic Tidal Current Surface Baroclinic Tidal Current Both barotropic and baroclinic tidal current are changed with stratification

  7. Subtle Stratification Change can make a difference. *Barolinic tidal forcing term, Baines (1982) F(N**2, Grad. h, Ub)

  8. Comparison of 8 Short Period Tides Empirical Solutions and FES 2004 Tide Model TOPEX+JASON Along-track Solution – FES 04: 2.4 cm RMS TOPEX+Tandem Mission Crossovers – FES 04: 3.5 cm RMS (squares) OSTST, Hobart, 3/07; OSU, JPL, NAO, Newcastle U., HK Polytech U.

  9. Comparison of 8 Short Period Tides Empirical Solutions and FES 2004 Tide Model (Alaska) TOPEX-only Along-track Solution – FES 04: 2.6 cm RMS TOPEX+JASON Along-track Solution – FES 04: 2.4 cm RMS OSTST, Hobart, 3/07; OSU, JPL, NAO, Newcastle U., HK Polytech U.

  10. Comparison of 8 Short Period Tides Empirical Solutions and FES 2004 Tide Model Multi-satellite Empirical Solution – FES 04: 2.2 cm RMS along T/P tracks (T/P, Tandem, Jason, GFO, ENIVSAT) 3.3 cm RMS at crossovers 4.6 cm RMS at all grid points TOPEX: 2.6, TOPEX+Jason: 2.4 (Along T/P tracks) OSTST, Hobart, 3/07; OSU, JPL, NAO, Newcastle U., HK Polytech U.

  11. Comparison of 8 Short Period Tides Empirical Solutions and FES 2004 Tide Model East China Sea Patagonia Shelf OSTST, Hobart, 3/07; OSU, JPL, NAO, Newcastle U., HK Polytech U.

  12. Comparison of 8 Short Period Tides Empirical Solutions and FES 2004 Tide Model • Changes of RMS Difference due to increased TOPEX data span in the coastal study regions • Alaska area: 2.6 cm to 2.4 cm (61 cm) • California (MB): 1.6 cm to 1.5 cm (44 cm) • Patagonia: 5.2 cm to 5.0 cm (66 cm) • East China Sea: 9.3 cm to 9.2 cm (56 cm) • NW Atlantic: 3.1 cm to 2.9 cm (41 cm) Preliminary Conclusions • Improved agreements with FES 2004by increasing TOPEX data span (O1, K1, P1, S2, and N2 tides) • Multi-satellite solution agrees with FES 2004 model better than Dual-satellite solution of TOPEX+JASON along T/P and JASON tracks OSTST, Hobart, 3/07; OSU, JPL, NAO, Newcastle U., HK Polytech U.

  13. Summary • Barotropic and baroclinic tidal solutions from altimeter observations prove to be useful to validate regional OGCMs. Marginal improvement observed in using multi-satellite altimetry in study regions. • Baroclinic tide amplitude and phase generated by model have significant correlation coefficients with TOPEX and GFO observations. Magnitude is smaller by a factor of 2-3. • Subtle changes in stratification can cause changes in tidal current in coast regions, which poses a challenge for tide-permitting forecasting systems. Future work: Regional model for Alaska, Improve tidal solutions

  14. Three Level Nested ROMS San Francisco Monterey Bay Los Angeles Monterey Bay 3-Level Nested Model Grid Size Time Step Res. L0: 85*170*32 900s 16.5km L1: 95*191*32 300s 5.3km L2: 83*179*32 100s 1.6km 16 Processors on SGI Altix 3000 1 hour integration takes 1min cpu time.

  15. Baroclinic Tide around Mendocino Escarpment J/m^2 J/m*m Energy Flux Baroclinic Tide Energy Consistent with observation (Althaus et al. 2003)

  16. Comparison with Tide Gauges RSS 3.51cm Monterey Domain 3 Gauges RSS 5.41cm US SW Coast Domain 10 Gauges Along the coast <10% of M2 amplitude

  17. Barotropic Tidal Current Comparison RMS/Mean (%) ROMS vs. TPXO.6 ROMS vs. ADCIRC RMS/Mean (%)

  18. Baroclinic Tide Theory Generation Baroclinic Tide Forcing Subscript i : Baroclinic Subscript 1: Barotropic Stratification, Bathymetry, Barotropic tide flux Energetics E: Baroclinic tide energy CgE: Baroclinic tide energy flux G: Forcing D: Dissipation Baines (1982), Gill(1982)

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