1. Numerical Modelling of SImPSon
Hans Burchard
Baltic Sea Research Institute Warnemünde
Bolding & Burchard Hyrodynamics
Bangor, 10-12/04/06
Simpson Retirement Conference

2. Simpson Retirement Conference
What is SIPS ?
Google says:
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Schweizerische Interessengemeinschaft für Polio-Spätfolgen
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...
Strain Induced Periodic Stratification
(search for 'sips john simpson bangor')
Bangor, 10-12/04/06
Simpson Retirement Conference

3. Simpson Retirement Conference
Tidal straining during ebb tide
Simpson et al. 1990
Bangor, 10-12/04/06
Simpson Retirement Conference

4. Simpson Retirement Conference
Tidal asymmetry (schematically)
Jay and Musiak 1994
Bangor, 10-12/04/06
Simpson Retirement Conference

5. Simpson Retirement Conference
Tidal asymmetry (numerically)
Burchard and Baumert, 1998
Bangor, 10-12/04/06
Simpson Retirement Conference

6. Simpson Retirement Conference
Tidal straining and estuarine turbidity maxima
Animation by Manuel Ruiz
Burchard et al. 2004
Bangor, 10-12/04/06
Simpson Retirement Conference

7. Strain-induced periodic stratification (SIPS)
(in Liverpool Bay, temperature & salinity)
Rippeth et al. (2001), Burchard (2002), Simpson et al. (2002)
Bangor, 10-12/04/06
Simpson Retirement Conference

8. (in Liverpool Bay, dissipation rate)
Strain induced periodic stratification (SIPS)
(in Liverpool Bay, dissipation rate)
Rippeth et al. (2001), Burchard (2002), Simpson et al. (2002)
Bangor, 10-12/04/06
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9. Simpson Retirement Conference
A simple model for SIPS
See also Sharples and Simpson (1995)
Bangor, 10-12/04/06
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10. Simpson Retirement Conference
Scaling of SIPS equations
See also Baumert and Radach (1992)
Bangor, 10-12/04/06
Simpson Retirement Conference

11. Simpson Retirement Conference
Two independent SIPS parameters
Bangor, 10-12/04/06
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12. Simpson Retirement Conference
Non-dimensional SIPS equations
Bangor, 10-12/04/06
Simpson Retirement Conference

13. Simpson Retirement Conference
Measure for SIPS intensity
See also Simpson and Bowers (1981)
Bangor, 10-12/04/06
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14. Simpson Retirement Conference
Example calculation for idealised SIPS
(Pg=0.2, Si=0.01)
Dimensionless relative buoyancy
Potential energy anomaly (dimless)
Dimensionless time
Dimensionless time
Bangor, 10-12/04/06
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15. Simpson Retirement Conference
Maximum potential density anomaly as function of Si and Pg  ~
No SIPS Pg Si
red: Pg · Si = 0.002
Bangor, 10-12/04/06
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16. Simpson Retirement Conference
Suggested condition for SIPS:
Bangor, 10-12/04/06
Simpson Retirement Conference

17. Simpson Retirement Conference
What we have ignored:
Varying sea level elevation
Non-zero mean surface slope
Varying horizontal density gradient
Bottom roughness to depth ratio
Earth rotation
Surface heat flux
Solar radiation
Surface momentum flux
Surface waves
Internal waves
Each of these processes would give us
at least one more dimensionless number
Conclusion: The real world is too complex for us to understand.
Bangor, 10-12/04/06
Simpson Retirement Conference