outline 1.brief overview of multibox model (john) 2.results of independent testing (katherine)...
TRANSCRIPT
Outline
1. Brief overview of multibox model (John)
2. Results of independent testing (Katherine)
3. Next steps for development (?) (John)
4. Overview of planned uncertainty testing (Tom)
Multibox PCB Model
CFWG Meeting
September 15, 2005
• Multibox ?– 50 Model Boxes
– 2 Vertical Layers
– 100 cm of sediments
• Physics Forced by:– Tides at Golden Gate
– ‘Delta Outflow’
– Local Tributaries
– Wind, Rain
PCBs in shallow sediments Version 2.0b
PCBs in channel sediments Version 2.0b
Independent Testing of SFEI’s Multi-box Model for PCB Fate and
Transport
Prepared by Tetra Tech, Inc.
Lafayette, CA
September 15, 2005
Next Steps for Model Development
Recommendations from independent testing:
• Documentation is outdated– Provide documentation sufficient to proceed with testing without
creating an extra report.• Include updating equations from draft report• Eventually document everything in a draft technical report
• Review and modify historic input data– Data are available, easy to update inputs
• Add variability to forecast data– Investigate applicability of alternative methods for generation of
forecast inputs
• Investigate sea level rise– Interesting question, out of the scope of this project
• Investigate impact of elevated SSC in Lower South Bay on PCB transport– Contribution to PCB mass transport is likely small,
though an investigation is warranted– Prefer to leave sediment model development to
Schoellhamer et al.
• Evaluate spin-up period. Investigate alternative initialization.– Significant consequences for PCB transport– Artifact of sediment model calibration– Lack data to change PCB initial conditions
• Include additional congeners– Yes
Recommendations from independent testing:
• Can Model / Data comparison be improved?– How good does hindcast need to be?– Probabilistic comparison may be useful– Loading function may be cause of overestimate
• Calibration (of loading curve?) Loading Curve
Recommendations from independent testing:
Estimated Timeline
Create documentation 3-4 days
Review/modify input data 2-3 days
Elevated SSC in LSB 2-3 days
Adjust spin-up period 4-5 days **
Additional congeners 2 days
Improve hindcast (calibration) 5+ days **
Total: 18-22 days
10-12 daysRed indicates steps ‘critical’ to continue with testing
Uncertainty Testing