Across Channel Momentum Balance

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Presentation transcript:

Across Channel Momentum Balance y z LNM h1 h2 Geostrophic balance (frictionless, steady and linear motion) in the lower layer

h z h1 LNM y h2 Geostrophic Balance in the upper layer Geostrophic Balance in the lower layer:

y z LNM h1 h2 h Margules’ Relation How about ? With one can determine

Effects of the Earth’s Rotation

Observed slope: 2m in 10 km 2 / 104 = 2 x 10-4 f = 8.8e-5 u1 = 0.08 u2 = -0.025 rho1 = 1020 rho2 = 1024

Could you draw the pressure field (isobars) associated with these salinity (density) fields? u1 = 0.10 m/s u2 = -0.05 m/s ρ1 = 1017 kg/m3 ρ2 = 1022 kg/m3 f = 8.8 e-5 s-1 Observed = 2 m in 8 km = 2.5 x 10-4 u1 = 0.08 m/s u2 = -0.06 m/s ρ1 = 1021 kg/m3 ρ2 = 1023 kg/m3 f = 8.8 e-5 s-1 Observed = 7 m in 8 km = 8.8 x 10-4

Internal Radius of Deformation Internal Rossby Radius Generally, the outflow modified by rotation will be restricted by the internal radius of deformation R, derived from geostrophy: Scaling: L Internal Radius of Deformation or Internal Rossby Radius

Framework established: Along estuary: pressure gradient balanced by friction Across estuary: geostrophic balance

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