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Xiaochun Wang Influence of Stratification on Semidiurnal Tides in Monterey Bay, California & Coastal Barotropic Tide Solutions 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 b a: Jet Propulsion Lab/California Institute of Technology b: Raytheon, ITSS. Validation of tidal solution. Influence of stratification
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Comparison with TOPEX Barotropic Tide Away from the coast Root of Summed Square 3.45cm <6% of M2 amplitude cm Tidal BC from TPXO6.0
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Baroclinic Tides Derived from Altimetry and ROMS 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 0.101 0.087 ROMS 1013 0.25 0.15 1.000 1.000 Significant at 99% level by Monte Carlo simulation. cm * Cycles used, TOPEX: 4-364, Tandem: 369-479, GFO: 37-168 Envisat: ~250 data points.
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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 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 Correlation coefficients and their significant level, 99% highlighted. Amplitude Phase
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Surface Tidal Currents with Different Stratification 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 Tidal Current Improved
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Barotropic and Surface Baroclinic Tidal Currents Barotropic Tidal Current Surface Baroclinic Tidal Current Both barotropic and baroclinic tidal current are changed with stratification
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Subtle Stratification Change can make a difference. *Barolinic tidal forcing term, Baines (1982) F(N**2, Grad. h, Ub)
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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.
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TOPEX-only Along-track Solution – FES 04: 2.6 cm RMS TOPEX+JASON Along-track Solution – FES 04: 2.4 cm RMS TidesTOPEX onlyTOPEX+JASONChange/Amplitude M2K1O1S2N2P1M2K1O1S2N2P1 1.01 1.16 0.83 1.61 0.57 0.54 0.95 1.16 0.71 1.53 0.52 0.53 -0.1% of 49 cm 0.0 % of 26 cm -0.7 % of 16 cm -0.5 % of 16 cm -0.5 % of 10 cm -0.1 % of 9 cm Total2.6 cm2.4 cm-0.2% of 61 cm Comparison of 8 Short Period Tides Empirical Solutions and FES 2004 Tide Model (Alaska) OSTST, Hobart, 3/07; OSU, JPL, NAO, Newcastle U., HK Polytech U.
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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 OSTST, Hobart, 3/07; OSU, JPL, NAO, Newcastle U., HK Polytech U. TOPEX: 2.6, TOPEX+Jason: 2.4 (Along T/P tracks)
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Comparison of 8 Short Period Tides Empirical Solutions and FES 2004 Tide Model OSTST, Hobart, 3/07; OSU, JPL, NAO, Newcastle U., HK Polytech U. Patagonia Shelf East China Sea
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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 2004 by increasing TOPEX data span (O 1, K 1, P 1, S 2, and N 2 tides) Multi-satellite solution agrees with FES 2004 model better than Dual-satellite solution of TOPEX+JASON along T/P and JASON tracks Comparison of 8 Short Period Tides Empirical Solutions and FES 2004 Tide Model OSTST, Hobart, 3/07; OSU, JPL, NAO, Newcastle U., HK Polytech U.
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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. 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. 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. 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
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Three Level Nested ROMS 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. Los Angeles San Francisco Monterey Bay
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Baroclinic Tide around Mendocino Escarpment Baroclinic Tide Energy Energy Flux J/m^2 Consistent with observation (Althaus et al. 2003) J/m*m
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Comparison with Tide Gauges Monterey Domain 3 Gauges US SW Coast Domain 10 Gauges RSS 3.51cm RSS 5.41cm Along the coast <10% of M2 amplitude
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Barotropic Tidal Current Comparison ROMS vs. TPXO.6 RMS/Mean (%) ROMS vs. ADCIRC
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Baroclinic Tide Theory Generation Energetics Baroclinic Tide Forcing Subscript i : Baroclinic Subscript 1: Barotropic G: Forcing D: Dissipation E: Baroclinic tide energy CgE: Baroclinic tide energy flux Baines (1982), Gill(1982) Stratification, Bathymetry, Barotropic tide flux
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