Oceanography

test 2

ocean currents

water masses in motion

surface currents

driven by wind, friction drags the water

deep currents

driven by density

wind is generated by

movement of air from areas of high-pressure to areas of low pressure

the earth is heated _____ by the sun, producing a simple ______

unevenly, circulation

corriolis effect

The effect of Earth's rotation on the direction of any freely moving object

- winds & currents

how long does it take for the earth to rotate completely

24h

depending on the latitude the speed of the earth's rotation changes

fast at the equator, slow at the axis (poles).

what happens to warm air

it rises because it has a lower pressure than cold air.

What will happen to air in adjacent latitudes?

!!!

Coriolis effect in opposite poles

apparent reflection to the right in the northern hemisphere and reflection to the left in the southern hemisphere.

the Coriolis effect results in the _____

three cell pattern of air circulation

wind cells are modified by the position of

the continents, their topography, the seasons, and chaotic, unpredictable variations

long term patterns and trends are understood but _____ fluctuations can be hard to predict

short -term

Intertropical Convergence Zone (ITCZ)

The latitude that receives the most intense sunlight, which causes the ascending branches of the two Hadley cells to converge

The Doldrums

a frequently windless area near the Equator

Oceanic Gyres

Large system of circular ocean currents

the force moving the gyres are

trade winds

trade winds are at the ___

equator

there are __ gyres

5

Ekman Spiral

surface winds drive surface currents, and each layer of water drags the layer below, but the Coriolis Force changes each layer's direction slightly to make a spiral effect

Water is ___ ___ as you go deeper, making it a spiral

more deflected

the amount of deflection in the Ekman spiral depends on the speed, but it is most commonly deflected at__

right angles (90*)

The Coriolis effect results in a continual deflection with depth. Some water is actually travelling in the opposite direction to the wind.

true

geostrophic flow

circular flow around the gyres, powered by the winds, modified by Ekman spiral and gravity

The net movement of water causes some water to pile up in the middle of gyres

gravity prevents the hills being too high

The Coriolis effect is stronger closer to the poles

this causes intensification of western boundary currents

western boundary currents -

tend to be narrower, deeper and faster than eastern boundary currents

eastern boundary currents

broader bands of conder water travelling into lower latitudes

North Atlantic gyre currents

North Atlantic Current --> Canary Current --> North Equitorial Current --> Gulf Stream

North Pacific Convergence zone

North Pacific current --> California Current --> North Equitorial current --> Kuroshio current

Sargasso sea

the middle of the North Atlantic gyre that is so still

The north pacific gyre has immense islands of floating garbage

the pacific garbage patch

Ocean eddie

Pinched off swirling masses of water

the inside of gyres are ..

isolated and often still and stagnant

_______ of water can pass through the gyre currents

the best example is the gulf stream

eddies are often the only means of mixing surface waters from one side to another

true

vertical stratification of the Ocean

the ocean is divided into horizontal layers, based on density.

Mixed layer

top layer

Pycnocline

a zone of rabidly increasing density

deep layer

relatively stable density. most of the ocean water

the increase in density of water is a reflection of the change in

Temperature, Salinity

Thermocline + Halocline =

Pycnocline

temperature is ___ significant than salinity

more

mixed surface layer

this water is usually well mixed by currents and weather.

- Uniform temperature and density.

pycnocline

can act as an effective barrier to vertical movement of water nutrients and many animals

- water currents are often moving in totally different directions above and below the pycnocline

deep-ocean currents and water masses

most of the deep ocean water have their origins in high latitude, surface waters

- dense and cold

- the difference in density between masses of water within the deep layer are slight, but enough to keep the separate with definite horizontal boundaries (mini pycnoclines)

- 10 miles per year

equatorial upwelling

even though the Coriolis effect is slight at the equator, some water is deflected towards the poles from the equatorial currents of the Atlantic and pacific Oceans.

upwelling of colder, but nutrient rich water results in

high biological productivity along the equator

equatorial counter current

a current flowing in the opposite direction of the prevalent wind flow

deep layer

most of the oceans mass is here, about 80%

- density increases slowly with depth

- water currents are slow and sluggish

coastal upwelling

where wind is blowing a certain direction down a coastline, the Coriolis effect can cause the water to flow offshore.

- there will be upwelling of deeper, colder, but nutrient rich water.

downwelling of surface water can occur along a coast if...

the winds are blowing in a certain direction

erosion

wearing down of land

main geologic process at work on land

erosion

main geologic processes at work in the ocean

deposition

deposition

accumulation of sediments

sediments and rock are composed of..

different minerals in various quantities

rocks

consolidated/hardened sediments

mineral is made of

available elements bonded together

A mineral:

a naturally occurring, inorganic substance, with a definite chemical makeup and crystalline structure

minerals crystallize, accumulate, precipitate, or are organically produced, and then combine in different proportions to form the different rocks.

true

igneus rock

solidified from molten magma or lava

metamorphic rock

changed by heat or pressure

sedimentary rock

compacted sediment

the rock cycle shows how

all the types of rock are all interrelated, and can change from one to another

Igneous rocks:

Granite (continental crust)

Basalt (oceanic crust)

sedimentary rocks:

lithogenous sediments, isogenous sediments, hydrogenous sediments, cosmohenous stuff

minerals are the _____ of rocks

building blocks

common minerals in and on the earths crust (4 important 1's)

Quarts, feldspars, clay minerals, calcite

Quarts caracteristics

Tough, resistant, not reactive, can get grind down into sand.

Feldspars reaction

When feldspars are exposed to the surface, they get chemically changes into clay.

When clay minerals get wet they become...

mud

calcite characteristics

abundant in biogenous sediments, plankton use this mineral to make their shells

what are turbidity currents

an avalanche that goes down the continental slope and builds the continental rise

Lithogenous sediments

grains of various sizes that are derived from the land (older rocks)

the amount of sediment depends on ...

topography , climate, and the type of rock rivers flow over.

___ are the main source of lithogenous sediments

rivers

most sediments come from ...

wet climates & mountain regions

lithogenous sediments are classified by their

grain size

Aeolian deposits

Wind-blown deposits

- arid environment with little vegetation

Aeolian deposits are

- fine grained, well sorted

Glacier sediments

- poorly sorted material of many grain sizes.

- rafting of large chunks into deep ocean

why is glacier erosion stripy

because joined glaciers don't mix, creating strips of different glaciers

shoreline erosion

- poor sorting

- depends on a # of factors such as exposure, topography, river discharge, weather, and seasons.

turbidity currents

- occur offshore