Phys Ocean Final

Front 1

What happens to entropy of a system at constant temperature when heat is added

Back 1

Increase due to first law of thermodynamics; change in internal energy = heat added/ subtracted to system -work done ( none because of constant temp)

Front 2

1. Describe changes that occur when fresh water freezess

Back 2

1. Forms tetrahedral (least dense structures) Goes through quartz structure from ball like.
2.

Front 3

relationship between

Salinity and constancy of composition.

Back 3

1. Salinity depends on constancy of composition (ratio of ions in ocean is constant because erosion over time)

Front 4

relationship between density and stability

Back 4

1. Stability depends upon vertical change in density (less dense above more dense = stable)

Front 5

1/rho*Drho/Dt

Back 5

changes in density following flow

Front 6

1. How do we use the conservation of volume to form simplified budgets?

Back 6

1. Discounting for changes in density and compressibility (because tiny compared to advection) we can use this to say that all change in budget must be advective changes; flow in or out must be balanced because volume is conserved.

Front 7

ficks law

Back 7

1. Kc = diffusion coefficient; dc/dc = concentration gradient

Front 8

what form does ficks law take if it changes spatially

Back 8

1. dc/dt = Kc*d2c/dx2… (y,z)

Front 9

1. What processes produce or contribute to the following short residence time of basin

Back 9

1. smaller basin volume greater inflow; Tres = Vol/Fin; large volume flux vs volume.

Front 10

1. Fog over the ocean produced by

Back 10

1. Upweling, cold surface water hitting warmer air
2.

Front 11

1. Increased upper ocean temperature vertical gradient produced by

Back 11

1. warmer seasons; less turbulence/mixing; daily temporal variation; add heat by heat flux and increase heat content

Front 12

1. Increased surface albedo produced by

Back 12

1. more reflection of insolation so less solar radiation is absorbed; w/ respect to sea ice: increased ice coverage leads to increased albedo, less heating absorbed by ocean and atmosphere ,and more ice formation - positive feedback

Front 13

draw inset temp, light, potential density vs depth

Front 14

sketch average distribution of SST, SSS, Precip

Front 15

Contributers for Qs, Qb, Qe, Qh

Back 15

Clouds (negative linear), SST, humidity (negative), Wspeed

Front 16

1. How does Newton’s First law of motion apply to ocean dynamics?

Back 16

1. Inertia: what is set in motion remains in motion; inertial forces are advection terms (u*dq/dx, v*dq/dy, w*dq/dz); they represent the velocities of flow and how that low changes when acted on by other forces. Not important in ocean flow when compared to Coriolis.

Front 17

1. What are the forces that act in the ocean interior?

Back 17

1. Gravity, Friction, Pressure gradient, Coriolis

Front 18

1. The hydrostatic balance is composed of what forces? State the forces and the direction of each.

Back 18

1. Gravity down, pressure up. rho*g*h = pressure. dP/dt = -g*rho

Front 19

1. Explain two mechanisms that create a horizontal pressure gradient in the ocean.
2.

Back 19

sea surface height; density changes

Front 20

1. What quantitative argument is used to show that molecular viscosity is not important in ocean dynamics?

Back 20

1. Reynolds number; Gulf stream conditions: L = 1000, V = 1 m/s. kinematic molecular viscosity of water = 10e-6. Re of gulf stream = 1000*1/10e-6 = 10e9. Only small reynolds numbers does molecular viscosity matter.

Front 21

1. For scale choices appropriate to large scale ocean, what two forces remain when small removed.

Back 21

1. Coriolis and horizontal pressure gradient

Front 22

1. Which non dimensional number is used to argue that the inertia terms are small in ocean circulation. Give the names of the non dimensional number, it’s mathematical representation and the forces it compares. At what scales would the inertia forces become important?

Back 22

1. Rossby NumbeR: u/f*L; inertia vs Coriolis
2. U2/L = fu ; U/f:
3. Inertia becomes important when coriolis is very small (low latitudes) or in lab when using a small environment and thus small L; fast speed or short scale

Front 23

1. What is the effect of the Coriolis acceleration and under what conditions is it important in ocean dynamics?

Back 23

1. Coriolis causes a deflection in the direction of the flow to the right of the wind in NH. It is Important to large scale ocean dynamics when the Ekman number Kz/fL (Ro, Re-1) is small.

Front 24

1. How is the geostrophic flow altered by horizontally varying water density

Back 24

1. f*dv/dz = -g/rho*drho/dx; in NH as move W - E, density decreases and geostrophic speed increases as you move vertically up in water column

Front 25

1. How deep into the ocean does the effect of surface wind stress extend and how is this depth estimated?

Back 25

* ~100 meters; estimated using Ekman number Ek ~ 1 => H~sqroot (Kz/f)

Front 26

1. Explain how winds blowing along a coast set up a near surface flow in the same direction as the wind. What direction must the winds blow to create upwelling?
2.

Back 26

1. East coast of US, winds blowing S to N along coast. Coriolis causes surface water transport to be from west to east (90º) right of winds. Higher pressure at right where water is piled, low where it’s removed. Water attempts to flow towards low, geostrophic force makes it go North.
2. Upwelling (cold, nutrient rich) then occurs at coast to replace lost water.

Front 27

1. What dynamical processes produce upwelling at the equator?

Back 27

1. Easterly trade winds blow from east to west along equator, forcing water transport N to in NH and S in SH. This water must replaced through upwelling.

Front 28

1. What is ekman pumping?

Back 28

1. As water blows on a location in NH, the point where it blows strongest will be surrounded on either side by weaker wind. Because water moves 90º right of wind, there is buildup of water to right forcing downwelling, loss of water to left forcing upwelling.

Front 29

1. What is the direction of the vertically integrated flow in the bottom frictional layer driven by an overlying geostrophic flow? Explain the forces that create this flow.
2.

Back 29

1. The direction of the vertically integrated flow in bottom friction layer is same as direction of pressure gradient. Above bottom you have geostrophic flow north (low pressure E, high pressure W). But as you descend, pg stays same but water slows due to increased friction. Since only two forces fv = 1/rho*dP/dx, and pressure doesn’t change, Coriolis must weaken. Thus the integrated bottom flow is 90º to the left of overlying geostrophic flow.
2.

Front 30

1. How is a temperature salinity diagram used to infer deep ocean circulation?
2.

Back 30

1. TS extremes are places of source waters. TS must flow from extreme to less; you can follow where/how this marked masses go. NADW acquires specific TS signatures at formation zone through convection cooling and because these properties are conserved you can determine where it is by locating this TS signature and using the Core method to determine fractional mixing amounts.

Front 31

1. Compare and contrast characteristics, formation areas, and flow of NADW and AAIW.

Back 31

1. NADW is formed through convection at ocean ventilation sites where high evaporation and heat loss to atmosphere occurs, resulting in cold salty dense water that sinks from surface to bottom in Greenland, Norwegian, and Labrador (little bit) seas and moves equatorward southward.
2. AAIW forms mostly in southern Pacific (little bit in Antarctic ocean) as it is subjected @ polar and subantarctic fronts; surface waters pushed below @ deeper isopycnals; moves equatorward (northward).
3. AAIW forms at shallower depth, is fresher and color than NADW.

Front 32

1. What is general structure of in subtropics? Sketch the structure of the currents for the South Atlantic, including the names and directions of flow of the currents.

Back 32

1. Poleward flowing WBC that are faster than equatorward flowing EBC. Gyre circulation clockwise in NH, counterclockwise in SH.
2. Brazil hits AACC, into retroflexed Agulhas into Benguela.

Front 33

1. Which phase of the monsoon results in high biological productivity in the Indian Ocean and why?

Back 33

1. SW because formation of N somali current on the eastern side of Africa in the Arabian Sea (warming of land mass in S Eurasia and N Africa causes winds to blow from cooler high pressure over water to lower pressure over land). Winds drive upwelling along coast which causes biological productivity.

Front 34

1. Why does the ocean sort itself into a limited range of TS space?

Back 34

1. Water mass characteristics set at surface - dense water is produced in a limited number of places with constant formation processes of initial water characteristics. Mixing is weak so formation characteristics are conserved.

Front 35

1. What would happen to the meridional overturning circulation if flow through the Indonesian Archipelago was blocked and why?

Back 35

1. Warm water return to the NA would slow and cool causing less ice melt and warmer temperature along MOC return path around western Europe and UK. Agulhas Current reduced heat transport to poles; pacific warms; MOC may get stronger.

Front 36

1. Sketch the along estuary vertical distribution of the salinity that would be observed for a) salt wedge and b) partially mixed estuary.

Front 37

1. Identify and sketch the vertical distribution of the forces that produce the sub-tidal circulation in an estuary.
2.

Back 37

1. Barotropic pressure dn/dx*g, created by an increase of SSH @ river input to estuary is balanced by Baroclinic pressure -g/rho*drho/dx*z, which strengthens with depth due to greater salinity at depth. Barotropic + baroclinic = turbulent friction

Front 38

1. Sketch the surface salinity that would be observed in a wide estuary that is influenced by the Coriolis force.

Front 39

1. The ENSO index is based upon what oceanographic property and where is this based? Why is this index important at a global level?

Back 39

1. The oceanographic ENSO index is based on SST. The atmospheric ENSO index is based on relative pressure differences over Tahiti and Darwin, Australia. Warmer SST spread out in pacific between these areas indicates a weakening of westerly trade winds, thus a relaxation of the thermocline and warmer SST spread over larger areas. The weakening of water transport E to W also causes less upwelling and less biological production in S America.
2. Severity and intensity of weather patterns at global scale is related to ENSO.

Front 40

1. What might the consequences be or coastal circulation of a) increased wind speed along the western Antarctic Peninsula, b) increased Arctic river flow, c) an increase in the number of warm core Gulf Stream rings?

Back 40

1. increased AACC, push it closer to AA continental shelf, increase cross shelf exchange rate. Interaction of current w/shelf in absence of slope sea will pull warmer, more saline CDW onto shelf. This warmer water will cause basal melting and sensible heat polynya formation, as well as cause grounding line of ice shelves to recede.
2. Increased arctic river flow may decrease seasonal summer ice in arctic. Increased freshwater would increase stratification.
3. Increase in warm core eddies shed off gulf stream will increase interaction of gulf stream with coastal ocean, such as Mid Atlantic Bight; cause increased flushing shelf which would have a range of biological effects.