Baroclinicity, Forcing Mechanism and Prediction of Chemical Propagation of San Diego Bay and Their Chemical Propagation of San Diego Bay and Their Effects on Naval Applications

Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications  INTRODUCTION  STUDY SITE  Forcing mechanism  Baroclinicity  WQMAP MODEL  MODEL EVALUATION  CHEMMAP MODEL  CHEMICAL THREAT SCENARIOS  CONCLUSIONS

INTRODUCTION/ IMPORTANCE  Littoral Waters: Special Operations, Mine Warfare, Expeditionary Warfare, Object Drift, Search and Rescue, Oil Spill  National Security: Prediction of propagation in case of Chemical Attack or accident  Model evaluations: Requirements for prediction of currents and tides worldwide Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications

INTRODUCTION/ PURPOSE  Determine how well 2D depth- integrated models will satisfy certain Navy applications in coastal bays.  Evaluate the models WQMAP - CHEMMAP purchased by NAVOCEANO  Apply the CHEMMAP model in different threat scenarios in San Diego Bay Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications

STUDY SITE - SAN DIEGO BAY  Importance: Large City, Host of a significant part of US Navy, near the borders  Oceanographic Interest: Small Tidal Basin, Semi- Enclosed Bay  Advantage: Historic Data Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications Zuniga jetty

STUDY SITE - CHARACTERISTICS  Average depth 6.5 m (measured from the mean sea level). Northern/outer part narrower (1-2 km wide) - deeper (up to 15 m). Southern/inner part wider (2-4 km wide) - shallower (less than 5 m).  Average temperature 21 C (range 14 – 26 C). Average temperature during summer (late June to late August) 23 C.  Salinity ( ppt) and average 35 ppt (in summer 36 ppt). Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications

STUDY SITE – FORCING MECHANISMS  Currents produced by tides (“tidal pumping” caused due to the flow difference between ebb and flood).  Winds insignificant effect. Both westerly afternoon winds and easterly morning/ evening winds less than 5 m/sec  Annual precipitation 0.26 m (in summer negligible – less than m). No significant river inflow Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications

BAROCLINICITY  Data used : 3 ADCP sites in summer 1993 (SPAWAR)   ADCP /velocity coefficient remarks  Nb1/u 97.16%  Nb1/v 96.32%  Nb2/u 91.89%  Nb2/v 94.71%  Bb/u 35.19%  Bb/v 92.94%  Bb/u 49.53% Filtered  Bb/v % Filtered Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications

BAROCLINICITY – EXCEPTION  u component near point Loma has great differences in surface and bottom.  Reasons for discrepancies:  Relatively open ocean (Influence of California Current as well as influence of Wind )  Data from ADCP very near to Zuniga jetty Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications

WQMAP MODEL MAIN EQUATIONS Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications

WQMAP MODEL - APPROXIMATIONS AND BOUNDARY CONDITIONS  Hydrostatic  Boussinesq  Land boundaries assumed impermeable (normal component of velocity set to zero).  At closed boundaries transport of substance (i.e. salinity) is zero.  At open boundaries, concentration specified during the inflow, using characteristic values. Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications

MODEL EVALUATION/ VELOCITY COMPONENTS Data/Model comparison: Mean values differences: 0.49–1.29 cm/s Deviation values differences: 0.44 – 6.70 Correlation Coefficient : % Root Mean Square Error: 6.73–9.02 cm/s Error Coefficient Variation:6.8 – Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications

MODEL EVALUATION/ ELEVATION Data/Model comparison: NOAA SPAWAR M2 (ampl dif) cm cm K1 (ampl dif) cm cm O1 (ampl dif) cm cm S2 (ampl dif) cm cm M2 (ph dif) o o K1 (phdif) o o O1 (ph dif) o o S2 (ph dif) o o Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications

MODEL EVALUATION/ CONCLUSION  2D Model satisfactory for well-mixed areas of the Bay (less accurate for the entrance)  Few Discrepancies due to proximity of ADCPs to the shore, bathymetry errors Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications

CHEMMAP MODEL  Predicts trajectory/ fate of floating, sinking, evaporating, soluble and insoluble chemicals and product mixtures.  Estimates the distribution of chemical elements on the surface, in the water column and in the sediments.  Langrangian approach Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications

CHEMMAP MODEL SELECTION OF CHEMICALS

CHEMICAL THREAT SCENARIOS 12 scenarios (6 chemicals in North and South San Diego Bay)  Methanol (1 barrel released in depth 1m).  Benzene (10 tons in depth 1m).  Ammonia (200 tons in depth 3m).  Chlorobenzene (200 tons in depth 3m).  Trichloroethylene (200 tons in depth 3m).  Naphthalene (200 tons in depth 3m). Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications

CHEMICAL THREAT SCENARIOS/ RESULTS NORTH SAN DIEGO BAY  In 3 hours: San Diego port/city  In 10 hours: Entire North SD Bay  In 12 hours: Outside SD Bay  In hours: Naval Station  In 5 days: Heavy impact on NS  In 20 Days: South Bay  In 32 Days: The entire SD Bay Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications

CHEMICAL THREAT SCENARIOS/ RESULTS SOUTH SAN DIEGO BAY  In 12 hours: Naval Station  In 15-17days: Small part of absorbed or dissolved chemical in San Diego city/port  After 32 days: No effect to North San Diego Bay Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications Comparison of different chemicals’ results after spilling in South San Diego Bay

CHEMICAL THREAT SCENARIOS RESULTS FOR FLOATERS  Methanol: after 3 days 45-50% in water column, after 20 days less than 5% - rest decayed.  Benzene: 45% evaporates. After 2 days 30-50% in water column, after 20 days 8-18% - rest decayed.  Ammonia: After 3 days 50-75% in water column, after 20 days 8-18% - rest decayed. Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications

CHEMICAL THREAT SCENARIOS RESULTS FOR SINKERS  Chlorobenzene: After 5 days % in water column, after 20 days 50-90% - rest decayed.  Trichloroethylene: After 5 days % in water column, after 20 days % - rest decayed.  Naphthalene (gas/air dispersed): After 5 days % in water column, after 20 days 12-33% - rest decayed. Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications

APPLICATION CONCLUSIONS Great danger/ vulnerability: Great danger/ vulnerability: In the North San Diego Bay, contamination of city/port, Bay – small reaction time. In the North San Diego Bay, contamination of city/port, Bay – small reaction time. In the South San Diego Bay, contamination only of Southern part (including Naval Station). In the South San Diego Bay, contamination only of Southern part (including Naval Station). When in the South, bigger percentage of chemical and for more time remains in the water column. When in the South, bigger percentage of chemical and for more time remains in the water column. Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications

GENERAL CONCLUSIONS San Diego purely barotropic San Diego purely barotropic San Diego Bay purely tidal forcing San Diego Bay purely tidal forcing 2D depth-integrated models should be applied to semi-enclosed, well-mixed, tidal basins. WQMAP - CHEMMAP far from perfect but useful 2D depth-integrated models should be applied to semi-enclosed, well-mixed, tidal basins. WQMAP - CHEMMAP far from perfect but useful Discrepancies mainly due to proximity of ADCP sites to shoreline, bathymetry errors Discrepancies mainly due to proximity of ADCP sites to shoreline, bathymetry errors Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications

RECOMMENDATIONS FOR FURTHER RESEARCH Use of better bathymetry, finer grid and more recent ADCP measurements (and more distant from the shore). Use of better bathymetry, finer grid and more recent ADCP measurements (and more distant from the shore). More detailed comparison of 3D vs. 2D model and application for drift and for instantaneous current prediction. More detailed comparison of 3D vs. 2D model and application for drift and for instantaneous current prediction. Classified thesis with data about real chemical threat (e.g. anthrax) - not available to foreigners. Classified thesis with data about real chemical threat (e.g. anthrax) - not available to foreigners. Baroclinicity, Forcing Mechanism and Prediction of chemical Propagation of San Diego Bay and their Effects on Naval Applications

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