Assumptions -PHYS OCE

assumptions of continuity equation

boussinesq approximation for an incompressible fluid (density change =0)

where are the equations of momentum derived from

newton’s 2nd law of physics

main forces in equation of motion

gravity, friction, pressure gradient, coriolis

how to know if a flow is turbulent

reynolds number

friction term in momentum equation

eddy viscosity

friction term in T/S equations

eddy diffusivity

assumptions of coriolis parameter

acts more in the x, y directions and gravity > coriolis in z direction, coriolis only acts horizontally

inertial motion

balance between acceleration and coriolis

inertial radius equation

V/f

inertial period equation

2pi/f

geostrophic flow

balance between coriolis and pressure gradients

assumptions in geostrophic flow

no friction, coriolis important, steady state, ocean currents horizontal (u,v), no wind stress

rossby number

coriolis important at small number, U/Lf

reynolds number

UL/v, large is turbulent

assumptions of ekman flow

steady state, no pressure gradients, no horizontal friction, constant vertical eddy viscosity (Az), constant wind, no deep flow, no waves/force besides wind stress

ekman flow

balance between coriolis and vertical friction

friction in ekman flow

wind stress in vertical direction

WBC vs EBC

WBC are stronger, narrower, deeper and EBC are shallower, wider weaker

sverdrup assumptions

steady state, no horizontal friction, constant wind, no deep motion for z, beta term

beta term in sverdrup

f = fo +βy

sverdrup balance

βMy = curlτ

what did sverdrup do

calculate circulation in upper oceans from wind stress

deficiencies in sverdrup

neglects boundary currents

stommel assumption

rectangular box with constant depth and density, steady state, simple wind

what did stommel do

how coriolis changes with latitude to understand WBC and EBC, sverdrup + simple bottom friction

munk solution

added eddy friction to consider more realistic basins, Ah

what does thermohaline circulation do

tells us how deep water masses are mixing in temp and sal

meddies

ATL inflow into MED and then outflow of MED into ATL that is dense and salty