Bangor, 10-12/04/06 Simpson Retirement Conference 1

Numerical Modelling of SImPSon

Hans Burchard

Baltic Sea Research Institute Warnemünde

Bolding & Burchard Hyrodynamics

hans.burchard@io-warnemuende.de

Bangor, 10-12/04/06 Simpson Retirement Conference 2

What is SIPS ?

Google says:

Social Inclusion PartnershipsStructural Insulated PanelsSignal Processing SystemsSecure Internet Processing ServicesStatistically Improbable PhrasesSchweizerische Interessengemeinschaft für Polio-Spätfolgen Società Italiana di Psicologia Side Impact Protection SystemStudent Intellectual Property Society ...Strain Induced Periodic Stratification (search for 'sips john simpson bangor')

Bangor, 10-12/04/06 Simpson Retirement Conference 3

Tidal straining during ebb tide

Simpson et al. 1990

Bangor, 10-12/04/06 Simpson Retirement Conference 4

Tidal asymmetry (schematically)

Jay and Musiak 1994

Bangor, 10-12/04/06 Simpson Retirement Conference 5

Tidal asymmetry (numerically)

Burchard and Baumert, 1998

Bangor, 10-12/04/06 Simpson Retirement Conference 6

Tidal straining and estuarine turbidity maxima

Burchard et al. 2004Animation by Manuel Ruiz

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

Rippeth et al. (2001), Burchard (2002), Simpson et al. (2002)

Strain induced periodic stratification (SIPS)(in Liverpool Bay, dissipation rate)

Bangor, 10-12/04/06 Simpson Retirement Conference 9

A simple model for SIPS

See also Sharples and Simpson (1995)

Bangor, 10-12/04/06 Simpson Retirement Conference 10

Scaling of SIPS equations

See also Baumert and Radach (1992)

Bangor, 10-12/04/06 Simpson Retirement Conference 11

Two independent SIPS parameters

Bangor, 10-12/04/06 Simpson Retirement Conference 12

Non-dimensional SIPS equations

Bangor, 10-12/04/06 Simpson Retirement Conference 13

Measure for SIPS intensity

See also Simpson and Bowers (1981)

Bangor, 10-12/04/06 Simpson Retirement Conference 14

Example calculation for idealised SIPS

Dimensionless relative buoyancy Potential energy anomaly (dimless)

Dimensionless time Dimensionless time

(Pg=0.2, Si=0.01)

Bangor, 10-12/04/06 Simpson Retirement Conference 15

Si

Pg

red: Pg · Si = 0.002

No SIPS

~

Maximum potential density anomaly as function of Si and Pg

Bangor, 10-12/04/06 Simpson Retirement Conference 16

Suggested condition for SIPS:

Bangor, 10-12/04/06 Simpson Retirement Conference 17

What we have ignored:

Varying sea level elevationNon-zero mean surface slopeVarying horizontal density gradientBottom roughness to depth ratioEarth rotationSurface heat fluxSolar radiationSurface momentum fluxSurface wavesInternal 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.