EPS SCI 15 - Lab 6 Study Deck

EPS SCI 15, Spring 2026

Density of Seawater (sigma)=

density - 1000

Stratification=

density top/bottom

Stable Water Behavior

Stratification <1, inhibited mixing

Unstable Water Behavior

Stratification >1, spontaneous mixing

Neutral Water Behavior

Stratification=1, easy mixing

Thermocline

region of rapid temperature change

Pycnocline

region of rapid density change

The thermocline and pycnocline are __ related

directly

Mixed Layer

top surface layer which interacts with wind and waves, mixes water, distributes heat, bottom boundary is thermocline

Depth of thermocline is ___ in the tropics.

semi permanent

Depth of thermocline is __ in temperate regions (deep in the _ season)

variable, summer

Depth of thermocline is __to __ in the polar regions.

shallow, nonexistent

Surface circulation is primarily driven by…

winds

The mixed layer is ___, while the bottom deep water is ___

turbulent, calm

If there was no rotation, there would be ___ circulation cell(s) and we would not observe the __ __.

one, coriolis effect

When the wind originates from the matching pole of the hemisphere, the coast experiences…

upwelling

When the wind originates from the opposite pole of the hemisphere, the coast experiences…

downwelling

In the southern hemisphere, the wind deflects…

left

In the northern hemisphere, the wind deflects…

right

Warm air rises near the equator and sinks at the 30 degree latitude of either hemisphere as its deflected.

The surface winds which flow towards the equator are the…

trade winds

Warm air rises near the equator and sinks at the 30 degree latitude of either hemisphere as its deflected.

The surface winds which towards 60 degrees latitude are the…

westerlies

Net transport of wind-driven ocean currents up to 90 degrees

Ekman Transport

Between which winds does equatorial divergence occur?

Trade winds

Between which winds does subtropical convergence occur?

Trade winds, Westerlies

Because the trade winds point toward each other, there is…

ekman suction, upwelling

Because the trade winds and westerlies point against each other, there is…

ekman pumping, downwelling

Four components of subtropical gyres:

Equatorial current/Trade winds, Western Boundary Current (HOT), West wind drift/Westerlies, Eastern Boundary (COLD)

The subtropical gyre in the Northern hemisphere is going… (**same dir. as high pressure)

CW, right

The subtropical gyre in the Southern Hemisphere is going… (**same dir. as high pressure)

CCW, left

Deep currents are driven by…

density forces

Deep currents’ driving force is…

gravity

Formation of deep water is primarily due to…

evaporation and formation of sea ice

Two Currents with Deep Water Formation

NADW, AABW

NADW

North Atlantic Deep Water

North Atlantic Deep Water

forms in Greenland, evaporation and cooling sinks water and flows south

AABW

Antarctic Bottom Water

Antarctic Bottom Water

Densest water (highest salinity, coldest)

Weddell Sea: Water from sea ice formation sinks and mixes with NADW to form…

AABW

Nitrogen concentrations are highest in the __ waters at __ latitudes in the __ Hemisphere.

surface, high, Northern

Oxygen concentrations are highest in the __ waters at __ latitudes in the __ Hemisphere.

deep, high, Southern

Intermediate water is relatively __ and flows out of the _ __ into the __ Ocean.

warm, Mediterranean Sea, Atlantic

The most nutrient rich current is…

NADW

How come NADW is the most nutrient rich?

oldest water, accumulates nutrients as its circulates in Pacific Ocean