Chem. Oceano. Unit 6: Water Masses, T-S Diagrams, Winds, + Currents

Water Masses

Have homogeneous T + S within them, that is different from others.

Surface Water Masses

Are affected by heat and FW exchange w/ the atmosphere + can be mixed by wind, waves, + tides.

Tracers

T + S are used as _____________ to track the origin + movement of water masses + to evaluate the degree of mixing (usually no mixing).

Central Waters (CW)

At the surface.

Intermediate Waters (IW)

Right below the surface.

Deep Waters (DW)

Deep below the surface.

Bottom Water (BW)

Directly above the sea floor.

Surface

The IW, DW, + BW all form oat the surface of the ocean.

Pacific Ocean

The ____________________ exhibits less complex stratification than the North Atlantic, sluggish circulation, + is uniform below 2000m.

Common Water (CoW)

Found in the Pacific Ocean and is mostly old NADW.

Indian Ocean

Exhibits the simpliest water masses that are truncated in the NH by Asia.

Red Sea Intermediate Water (RSIW)

Has a similar composition to MIW but is even warmer and saltier.

Caballing/Densification

When two meeting water masses have the same density is is called _____________ + the daughter becomes denser than both parents.

Vertical Structure

Describes which water mass is on top of which.

Stable

The quicker the increase in density w/ depth, the more _____________ the water column is.

Origin of Water

Described how the properties of local water masses compare to those of known origin.

NADW

Occurs at mid depths, despite having travelled 100s km from its source and is hardly modified by mixing.

AABW

The coldest water in the deep oceans + is identifiable at the bottom of the profile even though it has travelled 1000s km from its source (Antarctica).

AAIW

Found at ~880 m depths and has been considerably degraded by mixing w/ surface water above + deeper water below.

Consequences of the Coriolis Effect

1) Direction of winds

2) Direction of surface currents + gyre formation

3) Ekman transport

Air Density

Increases w/ pressure, temp, + decreasing humidity.

Rises

Less dense air ___________.

Sinks

More dense air ________.

High to Low Pressure

Winds near the ground blow from ______________________ pressure (poles to equator).

Gyres

Boundaries of _________ separate major surface water masses + outline the principle biological provinces in the open ocean.

Subtropical Gyres

Driven by trade winds + westerlies, curved by the coriolis and further modified by the presence of land.

- High T + S

- Supports small biomasses

Equatorial Currents

Are somewhat colder and lower in salinity than subtropical gyres and can support high biomasses.

Subpolar Currents + Small Reverse Gyres

Are low in T and mid-low in S, supporting biomass.

East-West

Open ocean circulation is primarily wind driven + is dominated by _____________ currents (ex. equatorial currents).

Boundary Currents

When currents from the open ocean encounter land, they are deflected by ________________________.

Western Boundary Currents

The strongest in the world + transport a considerable amount of heat to polar regions (ex. Gulf Stream).

Eastern Boundary Currents

Are slow + characterized by frequent upwelling events (ex. California Current).