OCS 1005 Exam 2

Principle of Bouncy

Things that have a high density sink, while things with a low density float.

Density Formula

Mass/Volume

what is the maximum weight of Pure Water?

1cm^3 weighs 1 gram at 4oC

Water compered to Air

Water is very dense compared to air.

How dose water temp affect density?

Water is less dense at a higher temperature.

* Maximum density of water is 4oC

Specific Heat (heat capacity)

Heat required to raise the temp pf 1 gram of substance by 1oC

Unit for SH: calories/gram/oC

* A smaller SH means it is easier to raise the temp.
* Land has a small specific heat and water has a large specific heat.

Calorie

Amount of heat requires to raise the temp of 1 gram of pure water by 1oC.

What is waters specific heat compared to land and air

Waters specific heat is much higher than land and airs.

Specific Sensible Heat

Change in heat measurable by temp change

* Qsensible = C\*M\*ΔT

Specific Latent Heat

Change in heat measurable by state change but has the same temp. (freezing/melting)

* Qlatent = L\*M


* calorie/g X grams
* Latent Heat of melting
* Latent Heat of vaporizing
* Water has the highest latent heat of vaporization of any known substance.

Evaporation < Precipitation

Heating of the ocean and atmosphere

Evaporation > Precipitation

Reducing heat of the ocean and atmosphere

Maritime Climate

Has small seasonal changes moderated by the ocean due to its large specific heat.

Continental Climate

Has large seasonal changes because of lands low specific heat.

Humidity

The saturation of water vapor pressure.

* When temp decreases the air can hold less water vapor

Salinity

The total mass amount of dissolved inorganic solid grams in 1 kg of seawater parts per thousand (%o).

* Surface salinity is determined by freshwater input at the sea surface

What is the typical salinity of seawater?

35%o

Forchhammer’s Principle / Principle of constant proportions

Although the salinity of various samples of seawater may vary the ratio of major salts is constant.

How to Measure Salinity

Old Method:

* 1.80655 x Chlorinity

New Method:

* measuring the electrical conductivity of seawater because salinity is proportional to electrical conductivity

CTD Rosette

Niskin Bottles are used to collect water a different depths.

Seawater

* When salinity increases so dose density
* When temp increases density decreases
* Two samples of water can have the same density at different combinations of temp and salinity.

Refraction

The bending of waves when waves travel frm one medium to another.

* Sunlight dose not travel well int he ocean causing scattering and absorption weaken light.
* Waves always bend toward slower propagation speed media.

What color dose Water transmit the best

Blue

Sound in Water

The speed of sound in seawater is about 1500 m/s

* The speed of sound in seawater increases as temperature, salinity, and pressure/depth increase.

Sofar (Sound Fixing and Ranging) Channel

Traps sound waves and the sound waves can propagate over long distances.

* minimum sound wave travel speed at 1000m
* Sofar channel is where sound travels the best in the ocean and is used by submarines.

Shadow Zone

The thin, high sound velocity layer which forms at a depth of 80 m that deflects sound.

* This is where submarines go to hide from sonar.

Active Sonar

When the sonar emits sound and listens for sound.

Passive Sonar

When sonar just listens for sound.

Side Scan Sonar

Has a transducer array that send and receive acoustic pulses that help map the seafloor or detects objects.

ATOC (Acoustic Thermometry of Ocean Climate)

Measures travel time of sound waves in the Sofar channel to detect small changes in temperature.

* sound travels faster in warmer water

Thermocline

Where temperature changes rapidly

Surface zone

The upper layer of the ocean, containing the least dense water and gets up to 18oC.

* This zone is only about 2% of the total ocean volume

Deep Zone

Underneath the thermocline and its average temp everywhere is 4oC.

* Comes into contact with polar regions where heavy cold water filling the deep zone is formed.
* This layer has the largest density with little change
* Contains 80% of all ocean water

Halocline

Where Salinity changes rapidly

Pycnocline

Where density changes rapidly

* density increases with depth
* Contains about 18% of all ocean water

Where is the temp highest?

In the northern Hemisphere near the equator

* hot and dry conditions near the tropic of Capricorn and cancer results in higher surface salinity
* Heavy rains near the equator freshens the ocean.

Heating and Cooling of Earth

* Heating comes from solar radiation
* Cooling is from radiation bouncing back from earth into outer space
* Earth maintains a constant temperature (Thermal equilibrium for Earth)
* Incoming solar radiation = back radiation

Electromagnetic Spectrum

The greatest intensity of incoming solar radiation is in the visible band of the spectrum.

Visible Band

Most of the energy is within the visible band where the sun makes the Earth the hotest.

Infrared Band

Where the earth is cooler and the sun can’t reach.

Greenhouse Gasses

* Carbon dioxide and water vapor absorb infrared radiation
* Ozone absorbs ultraviolet

Solar energy input varies with latitude

* Equal amounts of sunlight are spread over a greater surface area near the poles than the tropics
* Ice near the poles reflects much of the energy that reaches the surface there.
* Equator gets the most sun and the poles get the least.

Ocean and atmosphere redistribution of heat

The excess heat from the equator move toward the poles.

Heat transfer by ocean and atmosphere

Ocean heat transport dominates in the low latitudes while atmosphere heat transport dominates at high latitudes.

Convection

Movement of medium transports heat (effective)

* Warm air rises and clod are drops making a convection current
* Atmosphere convection comes from heating near the equator and colling near the poles

Conduction

Diffusion of heat from a higher temp to a lower temp. (not effective)

How are the 4 season formed

Earth’s rotational axis is tilted by 23.5o relative to the plane of it’s orbit around the sun.

* The seasons are caused by variations in the amount of incoming solar energy as earth makes its annual rotation around the sun on an axis titled by 23.5o.

Sea Surface Temperature in Northern hemisphere summer

* Warmer in the tropics
* Warmest in the western tropics except in the eastern Indian Ocean
* Cooler in the polar region (near freezing temperatures)
* Changes seasonally following the movement of the sun

ITCZ (Intertropical Convergence Zone)

Appears as a band of clouds near the equator

Sea Surface Salinity in the northern summer

* Fresher water in the polar region (due to melting ice) and coastal regions affected by large rivers
* Fresher water under ITCZ due to rain
* Salty water in the trade wind zone and in dry marginal basins (Red Sea, Mediterranean Sea, Persian Gulf)

Impact of freeing/melting at sea surface

Freezing: There is heat transfer (80 calories per gram) from ocean to atmosphere. Salinity of surrounding water increases (freezing expels salt from ice)

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Melting: Heat transfer from atmosphere to ocean. Salinity decrease due to the dilution of surrounding water.

Atmospheric Circulation

The large scale movement of air when solar heating is redistributed on the surface of the earth.

Coriolis Force

An inertial force that acts on the object with velocity that are in motion within the frame of reference.

* Pulls an object to the right in the northern hemisphere and to the left in the southern hemisphere

Coriolis Effect

An effect whereby a mass moving in a rotating system experiences a force acting periductular to the direction of motion and to the axis of rotation.

* Pulls an object to the right in the northern hemisphere and to the left in the southern hemisphere

Pressure Gradient Force

Wind blows from High pressure to Low pressure

Geostrophic Balance

The steady force balance between the Coriolis force and the pressure gradient.

Geostrophic Wind

Blows clockwise around high pressure system in Northern Hemisphere and counter clockwise in the southern hemisphere.

* High or Low pressure system will turn into an enclosed circulation forming an eddy.

Geostrophic Adjustment

The process of the atmosphere heating or cooling to reach Geostrophic Balance.

Isobars

Lines of equal atmospheric pressure drawn on a meteorological map.

Thermodynamic Law

* When temperature rises air volume increases and density decreases, this causes low pressure at earths surface leading to to storms.
* When temperature drops volume decreases and density increases, this causes high pressure and clear sky’s.

Convection Cell

A self contained zone where air is rotated based on temperature and is separated by density.

Hadley Cells (westerly Winds)

Tropical cells found on each side of the equator.

Ferrel cells (Easterly Wind)

Found at mid latitudes

Polar Cells (easterly Wind)

Found near The poles at high latitude

Doldrums

Calm equilateral areas where two Hadley cells converge.

Horse Latitudes

Areas between Hadley and Ferrel Cells

Trade Winds

Surface winds of Hadley cells

Westerkies

Surface winds of Ferrel Cells

Intertropical Convergence Zone (ITCZ)

Forms over the warmest water, and is characterized by cloudy and rainy conditions.

* Apreas as a band of clouds near the equator
* Migrated seasonally following the movement of the sun.

Walker Cell (walker circulation)

A temperature dependent circulation located near the equator.

* lower limb of the walker cell is the easterly trade wind system

Cold Front

Cold air mass is pushing warm air mass

Warm Front

Warm air mass is pushing cold air mass.

Storms

Regional atmospheric disturbances with high winds and precipitation.

* rotating masses of low pressure
* Transport heat from tropics to high latitudes

Extratropical Cyclones

Form at polar fronts

* transfer heat between polar cell and ferrel cell
* unstable and develops waves

Tropical Cyclones

* Transfer heat between Hadley cell and ferrel cell.


* Hurricanes
* Atlantic
* Typhoons
* Western Pacific
* Tropical Cyclones
* Anywhere else

Hurricanes

Gets most of its energy from latent heat of condensation from water vapor.

* Spins counter clockwise in Northern Hemisphere
* Spins Clockwise in southern hemisphere
* El Nino prevents Hurricanes

Sea Breeze (daytime)

When warm air rising from the land is replaced by the cool air coming off of the ocean.

Land Breeze (Night time)

When warm air rising from the ocean is replaced by cool air coming from land.

Monsoons

Patterns of wind circulation that change with the season. (dry winters and wet summers)

Island Effect

Precipitation is always on the windward side of an island.

Wind driven circulation

Near surface circulation directly driven by the wind.

Thermohaline Circulation

Deep water circulation driven by the changing the density of sea water form temp and salinity.

Subtropical Gyre

An area of anticyclonic ocean circulation that sits beneath a region of subtropical high pressure.

* Northern Hemisphere
* rotates clockwise
* Southern Hemisphere
* rotates counter clockwise

Ekman Transport

When ocean surface waters are influenced by the friction force acting on them via wind.

Geostrophic current

An oceanic flow in which the pressure gradient force is balanced by the Coriolis effect.

Western boundary currents (WBC)

Flows along the western boundaries of ocean in both hemispheres that are warm, narrow, deep and fast due to latitudinal changes in the magnitude of the Coriolis force.

* The Gulf Stream

Antarctic Circumpolar Current (ACC)

Steady unimpeded westerly wind blowing north of the Antarctic continent drives ACC which carries the largest transports of any currents and are cold, broad, shallow and slow and do not have well defined boundaries.

Water Mass

A volume of water with distinct temperature, salinity, and other water property characteristics that reflect the conditions of it formation region.

* Surface water
* Central water
* Intermediate water
* Deep water
* Bottom water

How is water mass formed?

Water mass is always formed at eh sea surface hen the deep zones comes into contact with the atmosphere in the polar region where heavy cold water filling the deep zone is formed.

Antarctic Bottom Water (ABW)

Tremendous cooling taking place near Antarctica continent produces the heaviest water mass.

North Atlantic Deep Water

Strong winter time cooling the Norwegian sea and Labrador sea produces it.

Which Sea is the saltiest and which sea is the freshest?

Saltiest: North Atlantic

* Due to excess evaporation
* Salty outflow from the Mediterranean

Freshest: North Pacific

* Due to excess precipitation

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Great Ocean Conveyor Belt

A circulation that carries surface after to the depths and back again. This process takes 1000 years to create newly formed North Atlantic Deep Water to reach the North pacific.

Upwelling

Divergence at the seas surface leads to colder water being pushed up.

Downwelling

Convergence at the sea surface leads to warm surface water being pushed down.

Low Pressure system

Storms bring colder rich subsurface water toward the surface, decreasing sea surface temp and bringing about higher biological productivity.

High Pressure System

Wind circulating around a high pressure system in both hemispheres causes convergence and downwelling in the ocean

Coastal Downwelling

When the Ekman transports moves water toward the coast.

Coastal Upwelling

Ekman transport moves water away from the coast.

Equatorial Upwelling

The rising of water along the equator from about 200m to the surface.

* typically in the eastern pacific