oceanography exam 2 study guide

define polar molecule

one end is positive and one end is negative

what property of water makes it good at dissolving salts

its polarity

what is hydrogen bond

electrostatic attraction between the positive end of a water molecule and the negative end of another water molecule

cohesion

like molecules stick together

adhesion

water molecules stick to other things

capillary action

cohesion + adhesion

what keeps water in its liquid state

hydrogen bonds

define heat

energy produced between the vibration of atoms or molecules

define temperature

a measure of an object response to input of removal of heat

describe the heat capacity of water

water has a very high heat capacity

how does the density of water change with temperature

warm water= less dense

cold water= more dense

why does water expand when frozen

below 4 degrees c, hydrogen bonds become rigid, causing the volume to expand as the mass stays the same

how much does water expand when it is frozen

it expands by 10 %

is ice more or less dense than liquid water

ice is less dense than lanquid

define brine rejection

exclusion of salts from crystal ice structure during seawater freezing, creating a very salty, very cold brine that sinks rapidly and is very dense

latent heat

heat change, but no change in temp, energy goes to changing state

sensible heat

temperature change when heat is lost

how does evaporation from the sea surface affect the salinity of the water and why

salinity increases with fresh water evaporating because the salt is becoming more concentrated

how does salinity of water affect the density

more saline= more dense

define isopycnal

a line collecting points of constant density in the ocean or atmopshere data

define thermohaline

decrease in temp with depth

define halocline

variation in salinity with depth

where in the ocean would you expect the most density stratification, and how does this effect vertical mixing

in the tropical and temperate zones, and this limits vertical mixing

define refraction

the bending of waves, usually while traveling from one medium to another

which colors of light are attenuated first and last in the ocean

red light is attenuated first and blue last is attenuated last

define weather

immediate state of the atmosphere in a specific time and place, not global

define climate

long term statsitical sum of weather conditions in an area

describe the chemical composition of dry air in percentage

78% nitrogen

21% oxygen

less than 1% other stuff

define residence time

average time a unit of substance is in a given location or condition

what is the residence time of water in the atmosphere

10 day s

how does humidity (water content) and temperature affect the density of air

warm air= less dense than cold air

more humid air= less dense than dry air

why is humid air less dense

because molecules of water vapor have less mass than nitrogen and oxygen molecules, which are being displaced by the water

what happens when a parcel of air rises in the atmosphere

rising air= expands, cools, low pressure, water condenses

sinking air= compression, warming, high pressure, no condensing

how does solar heating vary with altitude

poles absorb less, closer to the equator absorb more

how does solar heating vary with seasons

in the winter, each hemisphere is tilted away from the sun, receiving less radiation

how does solar radiation vary across time scales

this is caused by eccentricity, obliquity, and precession

how much heat does the atmosphere redistribute from the tropics to the poles relative to the ocean

atmosphere currents transport more heat poleward,

2/3 of heat transport

define coriolis effect

the observed deflection of a moving object, caused by the moving frame of reference

what direction does the earth rotate in the northern hemisphere

clockwise

what direction does the earth rotate in the southern hemisphere

counterclockwise

what direction does air turn in the northern hemisphere due to the coriolis effect

air turns right leaving the equator

what direction does air turn in the southern hemisphere due to the coriolis effect

air turns left leaving the equator

why are moving objects deflected in different directions in the north and south

because it is turning east in both hemispheres, we are just facing a different direction

what are the driest latitudes called and where are they

horse latitudes

they are at 30 degrees

this is because air is sinking, high pressure= less rain

what are the wettest latitudes called and where are there

the equator, 0 degrees, warm air is rising and condensing

define the ITCZ

intertropical convergence zone, aka doldrums, very little wind

why is the ITCZ tend to be north of the geographical equator

there is more land north of the equator, and this heats better than water

what direction do the easterlies blow

from east to west

what are the trade winds

steady surface winds of the hadley cells

what are the westerlies

steady surface winds of the ferrel cells

where are the doldrums and why is there little wind

the equator, there is little wind because the air is converging between the two hadley cells

where is the horse latitudes and why is it there so little wind

30 degrees, there is little win because it an area of convergence between the hadley and ferrel cells

relationship between monsoon and sea breeze

sea breeze is a small scale monsoon

how do monsoons and seabreezes occur

1. In the summer= controlled by a more northern ITCZ

   1. Land is warmer than the ocean

   2. Moist air blows from above ocean to land

   3. Moisture condenses and becomes rain

2. In the winter= controlled by a more southern ITCZ

   1. Land is cooler than the ocean

   2. Dry air blows from land to ocean

   3. Warm air rises, condenses and rains

in which directions do cyclones turn in the northern hemisphere

counterclockwise

what direction do cyclones turn in the southern hemisphere

clockwise

why no hurricane on equator

no coriolis

what three forces drive the circulation of the ocean

wind (friction on the oceans surface), rotation (coriolis forces on moving water), and gravity (differences in densities)

what direction do gyres turn in the northern hemisphere

clockwise

what direction do gyres turn in the southern hemisphere

counterclockwise

why is the theoretical net ekman transport of water 90 degrees from the wind direction

Only the surface layer feels the wind , and each layer feels the movement of the layer above it and moves more slowly as energy is lost through friction, and decreases and spirals down until the flow is the opposite of the wind

what two forces drive the circular flow of oceanic gyres

the pressure gradient and the coriolis effect

where are the five major gyres in the ocean

north and south atlantic, north and south pacific, indian ocean

how does the antarctica circumpolar current affect the biology of the southern ocean and the temperature of antarctica

it drives large scale upwelling and high productivity

it keeps warm equatorial water from reaching antarctica

is there high or low productivity in the center of gyres and why

low productivity in the center of gyres, there is no nutrients rising from the depths

what are some issues with ships towing nets to clean up the pacific garbage patch

they catch fish

they are costly

we need to get rid of the trash once we pick it up

explain the mechanism of westward intensification

coriolis effect is stronger further from the equator

as current flows poleward, it gets deflected sooner

because of steeper slope, the water on the western side flows faster and deeper

characteristics of western boundary currents

narrow, deep, warm, strong current, less nutrients

characteristics of eastern boundary

broad, shallow, cold, weak, slow currents, nutrient rich, bring cold water to the south

what kind of current is the gulf stream and what is its impact on the climate of the bordering land

it is a western boundary current and it transports warm water north and keeps northern europe temperate

how does upwelling effect productivity

brings up cold, nutrient rich water to the surface

how does downwelling impact the bordering land

it brings down water, supplies deeper ocean with dissolved gasses

what occurs at the equator, up or down welling

upwelling at the equator because the north equator is veering right and the south equator is veering left, diverging water pulls water up from the depth to fill in the gap created

how does coastal upwelling develop

water moved offshore by ekman transport is replaced by cold nutrient rich water

how does coastal downwelling occur

ekman transport brings in water, which accumulates on the coast, while surface winds blow parallel to a coastline

what is the trigger for an el nino event

unknown, it happens sort of cyclically

how does el nino effect water temp and productivity in the eastern pacific

trade wind weakens, pileup of warm water slumps eastward, stops upwelling and warms the americas

what drives thermohaline circulation

density and gravity

how does deep water form

in the great ocean conveyor belt, aka thermohaline circulation, water of different temperatures and salinity can have the same density, and deep water is formed by cooling and bring rejection

where is most deep water formed

north atlantic (greenland) and antarctica

in what pattern do water molecules move when a wave passes through

they move in a circular, orbital pattern

define wavelength

the distance between two consecutive, corresponding points of the same phase, such as two adjacent crests or troughs

define frequency

the number of wave cycles that pass a specific point in one second

define period

the time required for one complete cycle of a wave to pass a fixed point

at what depth below the still water level does wave motion become insignificant

the orbital motions of the water molecules become smaller with depth, and are insignificant by the depth equal to one half of the wavelength

define seiche waves

rock back and forth in a confined space, can be initiated by tides, storm surge, and are rarely destructive

define free wave

moving without further influence of the force that formed it

define forced wave

wave continually maintained by the force that created it (wind waves under a steady breeze)

define deep water wave

move through water deeper than half their wavelength, they never feel the bottom

define shallow water wave

they move through water less then 1/20th of their wavelengths, and begin to break

what does longer wavelength do to a wave

the wave moves faster

what is the equation for celerity (aka speed)

celerity= wavelength / period

what happens when a deep water wave approaching the shore reaches a depth one half the wavelength

deeper water wave turns in to a shallow water wave near the shore, and the wave begins to touch the bottom and become less stable, it begins to break

after a big storm at sea, do you expect the big waves or the small waves to reach shore first

big waves reach the shore first because speed is proportional to wavelength

define internal wave

form between ocean layers of different densitties

what role can internal waves play in the surface ocean ecosystem

they are generated by current flow over bottom topography, and they are important for mixing nutrients up in the photic zone, and fertilizing phytoplankton

define storm surge

dome of water formed under a storm, that is pushed on shore with the storm (a storm is a low pressure system, aka the air is going UP, pulling UP the water)

what events create tsunamis

created by sudden displacement of water by tectonic activity, landslides, icebergs falling from land or asteroids

what is a warning sign that a tsunami is approaching

the water retreats dramatically

what forces create two tidal bulges

GRAVITATIONAL FORCE and INERTIA aka centrifugal

the moon pulls one side towards itself, and inertia pulls the opposite side