EAS 212 The Oceans

What are the 3 ways to measure current?

subsurface floats, current meters, Acoustic Doppler Current Profilers (ADCP)

What is ARGO?

Autonomous drifitng floats. 100s were deployed. Measure temp/salinity/ ect

Describe an Ice tethered float?

fixed to the sea ice in the arctic ocean. A CTD profiler moves up and down line

WHat are the 4 oceans called?

arctic (smallest & shallowest), pacific (largest & deepest), atlantic (2nd largest), indian (mostly in southern hemisphere), southern (antarctic convergence)

What are the three ocean provinces?

continental margin, deep-ocean basin, mid-ocean ridge

What are some traits of the continental margin?

continetal shelf (almost flat), shelf break (location w/ increased slope), continetal slope (increace slope angle), continental rise (transisiton zone)

What are the 2 traits of the continetal margin?

canyons, and ground bedding (deposit largest sediment on bottom)

What are some traits of deep-ocean basins?

trenches (convergent active boundaries), abyssal plains (deep flat sediment), seemounts (pointy tops near volcanic centers), guyots (volcano with flattened top)

What is the Pacific Ring of Fire?

majority of earths active volcanoes and earthquakes (convergent plate boundaries)

What is the difference between an oceanic ridge and an oceanic rise?

slow spreading steep slope (rugged) and fast spreading gentle slope (less rugged)

What are pillow lavas?

smooth, rounded lobes of rock

What are hydrothermal vents?

water entering cracks, heated, released

What is the difference between an ocean and a sea?

sea is smaller and shallower, salt water, usually enclosed by land, directly connected to ocean

How much of the world is ocean?

70.8%

Which has a larger elevation oceans or continents?

oceans

What is bathymetry?

the measurement of ocean depth, charting of shape, or topography of floor

What does it mean that the deep ocean floor has relief?

there is variations in sea floor depth

What is sounding?

Letting out a rope with weight until it hit the bottom. Used to be measured in fathom (6ft length of an outstrechted arm

Describe echo sounders.

SONAR. sends signal downward and listens for echo. depth=(1/2)*v*t

How do satellites view images of the sea floor?

using RADAR altimetry. Global coverage but low resolution

What are the two major parts of the ocean?

Ocean florr and seawater

What are van der waals forces?

weak interactions when molecules are close together

What i the difference between heat and temperature?

energy moving with gradient and average kinetic energy

What is sensible heat?

heat added or removed that raises or lowers the temperature but does not change its phase

What is latent heat?

heat added or removed that does not change the temperature but leads to a phase change

Does water have high or low latent heats?

high (requires a lot of heat)

Wht is the term used to describe how the ocean does not greatly change in temperature diurnally?

global heat budget

What is the top layer of water called?

The photic (euphotic) zone. about 100m

What happens to light in semi-turbid waters?

Shifts green

What colour penetrates water the best?

blue

How does sound behave in regards to salinity, temperature, and pressure?

directly related

What is the shadow zone?

a region where sound pulses can’t reach

What is a sound channel?

a region associated with sound speed minimum where sound waves that enter are trapped. Great distance

What is acoustic thermography?

technique to precisely determine travel times in water over large distances by noting how sound changes with temperature

What are the three ways that solar radiation varies?

daytime vs nighttime, seasons, latitude

Where do the solutes in the ocean come from?

weathering and erosion of continental rocks

Whats the equation for concentration?

concentration= rate it enters and rate its removed

What is residence time?

the average length of time that a substance resides in the ocean

what are the numbers for major, minor, and trace?

major>100ppm>minor>1ppm>trace

What is the residence time for sodium?

260 million years

What is salinity?

total amount of solid material dissolved in sea water

Whats the equation for salinity?

grams of dissolved salts/ kg of seawater

What are the processes that effect salinity?

precipitation, evaporation, runoff, ice melting, and sea ice forming

Where is sea surface salinity (SSS) highest?

in subtropical regions

Is salinity higher in the atlantic or the pacific?

atlantic

what is the relationship between temperature and density?

inversly except at freezing margin

How are density and salinity related?

directly

how does an egg behave in freshwater vs salt water?

sinks vs floats

Does changes n temperature have a large effect on the denisty of cold waters?

no

What is the equation of state?

a comlicated equation describes how ocean density depends on T and salinity (and pressure)

In practice water equation do we use?

density(S,T,p)-1000kg/m³

What is the effect of non-linear equation of state?

the mixture of two water masses with the same density but different T/S can result in a mixed mass of higher density

What are the 3 clines?

thermo (temp gradient), halo (salinity gradient), and pycno (density gradient)

What is potential temperaure?

The temperature a parcel of seawater would have if lifted adiabatically to the sea surface (remove effect of pressure)

Where can you find extreme haloclines/ thermclines?

minimal vertical mixing. epishelf lakes ( ice covered and dammed freshwater lake floating n saltwater), cenotes (underwater caves where bottom is flooded with seawater and top is filled with rain/ runoff)

How do the mixed layers change with the seasons?

normally deepest in winter and shallowest in summer

What are some factors that control mixed layer depth?

wind driven mixing, stability of underlaying water, surface buoyancy changes, large scale ocean cirulatial

What is more important in the tropics?

salinity

What are the two main types of circulation systems in the ocean?

wind driven surface and deep-water density driven

What is a water mass?

a body of water with a specific set of charactersitics/ properties

How are water masses identified?

where they were formed and which position in the water column they occupy (intermediate, deep, bottom)

What type of plots can be used t identify water masses?

plots of salinity as a function of temperature (T-S) plots

What is an isopycnals?

lines of equal density

What are the three dominent forces in the ocean?

friciton, gravity, coriolis

Which direction does the earth rotate?

east

What does the coriolis effect do

change the intended path of a moving body in a rotating system

Which direction will objects go in the northern hemisphere?

Right of its intended direction

Which direction does an object go in the southern hemisphere?

left from its intended position

How does the coriolis effect change with velocity and latitude?

increases towards the poles and velocity

What causes the coriolis effect?

the difference in velocity of different latitudes on earth

What is the general composition of the atmoshere?

nitrogen, oxygen and other gases and water vapour

What is the lowest layer of the atmopshere?

troposhere

What is the saturation vapour pressure?

the max amount of water that can be held as vapour in the air

Which is less dense? Moist air or dry air?

less dense

What is adiabatic expansion?

as the air rises the pressure decreases causing the air to expand and cool decreasing the SVP

What is the pressure like at the equator and poles?

low, high

Describe the trade winds

from subtropical highs to equatorial low (winds are named for the direction from which they are blowing)

What is the doldrums?

region along the equator where the northern and southern hemisphere trade winds converge (today called intertropical convergence zone)

What are horse latitdues?

boundary between trade winds and the prevailing westerlies (@ 30N and S)

What is cyclonic flow?

counterclockwise around a low in northern hemisphere and clockwise around a low in southern hemisphere

What are the two ways that wind generate movement in the ocean?

by transferring its energy to the surface water through friction and by blowing/pushing the waters in a given direction creating slope on the sea surface

How much wind enegy is converted to kinetic ocean energy?

1-3%

Explain ekman spiral

As wind blows top layer the layer below is moved by friction ect ect. Coriolis effect deflects the motion into a spiral

Whch direction is total transport of water in each hemisphere?

90 degrees to the right of the wind in northern hemisphere and to the left in southern hemisphere

How do we get upwelling?

when winds blow away from an area we get divergence which causes the water to upwell from below (brings up cold water)

How does downwelling occur?

winds blowing towards an area lead to convergence of ocean currents. (somtimes called subduction)

What are some other causes f upwelling and downwelling?

offshore winds, eafloor obstructions, sharp bends in coastlines

how is productivity in downwelling zones?

low because nutrient cold water is not constantly upwelled to surface

Does the mean flow in deeper layers always mach ekham transport?

no as pressure gradient can happen at any depth

how do we get geostropic current?

as a parcel is set in otion by pressure gradient force coriolis effect acts on it unti it is no longer directly down the gradient and the forces balance out

What are gyres?

closed circulation oops within the ocean

what is the only current to flow all the way around the world?

anartic circumpolar current

How does sea level in the subpolar gyres and sub-tropic gyres differ?

low in sub-polar and high in subtropics

What is western intensification?

phenomenom of currents along the western boundaries being intensified

What are the traits of western boundary currents and eastern boundary courrents?

Fat, narrow, deep and slow, wide, shallow

What is a front?

encounter of two water masses/ currents with distinct characteristics

What are meanders?

snake like bends in the current. If a meaner is tight enough it pinches off forming and isolated ring

What are eddies?

large, rotating, whirlpool like currents

What cause warm and cold core rings

strong fronts separating cold water to the north of the gulf stream the rings will either contain water that is warmer or colder than its surroundings

How do warm and cold rings spin?

warm spin clockwise and cold spin counterclockwise