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

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

Baroclinic Tides Derived from Altimetry and ROMS Satellite Sample # Mean Amp Std Amp Corr (Amp) Corr (Pha) TOPEX T/P-Tandem GFO ROMS Significant at 99% level by Monte Carlo simulation. cm * Cycles used, TOPEX: 4-364, Tandem: , GFO: Envisat: ~250 data points.

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

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 Hourly forcing Experiment 4 Data-assimilated initial condition of Aug Monthly forcing Tidal Current Improved

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

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

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.

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 M2K1O1S2N2P1M2K1O1S2N2P % 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.

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)

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

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.

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

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 hour integration takes 1min cpu time. Los Angeles San Francisco Monterey Bay

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

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

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

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