Introduction to Physical Oceanography

Lect rer Dr Eng Hendra AchiariLecturer: Dr.Eng Hendra AchiariWeek 4

Basic Equation

Earth-Atmospheric system &Heat Balance

Conservation laws (Basic equation of Fluid Dynamics)

Conservation of Mass Continuity eq.Conservation of Mass Conservation of Momentum Conservation of Energy

C ti f A l M t

Continuity eq. Momentum (NS) eq. Heat budget / Wave eq C ti f V ti it Conservation of Angular Momentum Conservation of Vorticity

Dominant Forces for Ocean DynamicsDominant Forces for Ocean Dynamics

Gravity : pressure gradient, buoyancy and tides Coriolis : lt f ti i t ti di t Coriolis : result from motion in a rotating coordinate sys. Friction : due to relative motion between two fluid

particle & Wind stress is important friction forceparticle & Wind stress is important friction force.

Other forceAt h i Atmospheric pressure

Seismic

Type flow in the OceanType flow in the Ocean

General flow : the permanent time averaged circulationGeneral flow : the permanent, time averaged circulation Abyssal (Deep circulation) in deep ocean

driven by mixingdriven by mixing Wind driven Circulation: Caused by local wind Gyre: wind driven cyclonic/anticyclonic current with dimension

nearly ocean basin

B d t Boundary currents: parallel to the coast Jet : long narrow current Mesoscale eddies: spinning flows

Oscillatory flows due to wavesOscillatory flows due to waves

Planetary waves : rotation of earth Kalvin wavePlanetary waves : rotation of earth, Kalvin wave Surface waves: gravity waves

I t l Internal waves: change density with depth Tsunami: generated by earthquake Tidal currents: currents associated with internal wave

driven by tidal potential

Edge wave : surface waves confined to shallow regions near shore.

Conservation of Mass and Salt(bulk formula)

Can be used to obtain useful informationCan be used to obtain useful information about flow in the ocean ( a basin)

Can calculate the latent heat flux over the Can calculate the latent heat flux over the surfaceC l l t t ti k i li it Calculate net evaporation knowing salinity of flow in Si and out So, together with a

h ti t f t V fl i t frough estimate of water Vo flowing out of a basin.

Total DerivativeTotal Derivative

Total derivative (cont )Total derivative (cont.)

Momentum EquationMomentum Equation

Momentum Eq (Cont)Momentum Eq (Cont)

ContCont

Conservation of MassConservation of Mass

Conservation Mass (cont)Conservation Mass (cont)

ContCont.

ContCont