Chapter 8

Michael Slemp

*Marine Biology

Octopus• Is cephalopod mollusc• Octopuses have two eyes • 8 arms with suction cups• Hard beak in the mouth• Octopuses have no internal or external skeleton • One of the most intelligent

of all invertebrates• To defend themselves, they release ink (melanin = same as your

hair and eye color), use camouflage and arm autonomy (detaching of arm)

• All octopuses are venomous• Short life expectancy (6months-5 years). Die shortly after

reproduction • They have 3 hearts ( 2 pumps blood thru gills and 1 thru body)• They eat crabs, other molluscs (clams), fish, other cephalopods

What is AIR (atmosphere)? Gase

sNitrogen 78 %Oxygen 21 %Argon 1%Carbon Dioxide 0.03%All other gasses 0.01%

See pie chart in your book page 8-4

Water vapor

Aerosol

Water vapors are invisible. The

reason clouds are white is because the water have condensed

Aerosol is liquid and

solid particles suspended in air (like dust, pollen, ash)

Water vapor and aerosol makes about

4% of air)

Atmospheric layers

Troposphere: from sea level up to 15,000 meters (49,200 feet)Contains most of the air. Air compresses under its own weight = higher air

pressure

Stratosphere: up to 50,000 meters (164,000 feet)Has the most ozone!

Mesosphere: up to 100,000 meters (360,800 feet)

Thermosphere: beyond 110,000 meters (360,800 feet) into space

What is ozone?• Gas composed of 3 oxygen atoms (O3)

• Normally oxygen molecule has 2 oxygen atoms (O2)

• Extra oxygen in ozone causes instability and increased reactivity

• Ozone is mostly in stratosphere and absorbs the UV light (radiation from sun)

• Ozone protect us. If there would be no ozone, the UV light would kill the life on our planet

• In 1974, scientist came out with theory that ozone interacts with CFCs (chemical found in aerosols and air conditions)

• Reaction of ozone with CFCs can cause ozone hole and effect life on planet Earth!

Scientists are monitoring the size of the ozone hole existing over Antarctica

How much water vapor is in the air?

That depends on temperature, density and pressure

As temperature increases, pressure increases and density decreases

• Adding water vapor decreases air density even more

• Air is denser than water vapors

• Warm, moist air is less dense than cold air.

• Two air masses of the same temperature can have different densities

• It depends on the amount of water vapor

• Air with more water vapor is less dense

EvaporationAdds water

vapors into the air

CondensationRemoves water vapors from the

air

Saturated airAir in which the rate of

evaporation and the rate of condensation are the

same.The amount of water vapors is unchanged.

What happens when saturated air warms

up?• It becomes

undersaturated.• Evaporation adds

more water vapors into undersaturated air.

What happens when saturated air cools down?

• There is increased condensation • Water vapors are removed from air in

form of rain or snow (if temperature is low enough)

• Initially water droplets or ice crystals are very small and remain suspended in air

• As they collide, they form bigger drops or clusters or ice crystals. This lead to rain or snow

• Rain and snow happens when warm moist air mass collide with cooler air mass

Why is this important?• Air movements redistribute heat around the Earth• Precipitation is our main source of fresh water• All underground water, rivers, lakes get their water from

rain and snow. They return water and nutrients back to the ocean

Earth’s heat balanceSun is the

major energy source for

Earth’s surface

Atmosphere either absorbs or reflects 45%

of sunlight

20% absorbed by clouds and atmosphere

25% reflected by clouds and atmosphere

55% of sun’s energy reaches Earth’s surface

50% is absorbed by

Earth’s surface5% is reflected

by Earth’s surface

20%

25%

50%

5%

Earth’s heat balance

At any time, only half of the Earth’s surface receives sunlight (makes day and night)The energy coming to earth is ultimately lost as heat radiating back into space

What is solar energy?

Visible light

UV light (ultraviolet

light)

Infrared light

Makes it through the

atmosphere to Earth with

little absorption

Is absorbed mostly in

stratosphere by the ozone

layer

Some is absorbed by carbon

dioxide and water in stratosphere

and troposphere

Earth’s heat balanceSolar Energy is reflected

from various surfaces like • clouds• atmospheric particles• snow • reflective objects on

Earth’s surface

ALBEDO• The measure of amount

of energy something reflects

• Snow has high albedo• Black sand has low

albedo

Yellow = reflection, red = absorptionLeft arrow – snow, right arrow -water

To maintain balance between incoming energy from sun, eventually all energy Earth absorbs reradiates through

various paths back to space as infrared radiation

Unbalanced energy = Earth gets hotter,

less likely we survive!

Greenhouse effect • Important for life on Earth

• Atmosphere, after it absorbed infrared radiation, reradiates a lot of the heat back to Earth’s surface

• Most of the heat is collected in troposphere and stratosphere layers

• Without Greenhouse effect Earth would be on average 35°C (95°F)

The concern is that increased carbon dioxide and other heat-retaining gasses will cause global warming and increase the overall

temperature on Earth!

Uneven Heating• If there would be even heating on earth, there would be little

changes in temperature and no seasons

• But we know that there are seasons and temperature changes

• There are 3 primary factors that cause the Earth to heat unevenly:

1. Earth is spherical2. Earth’s axis of rotation is tilted3. Distance between Earth and sun varies with the time of

the year

Uneven Heating1. Earth is spherical

• Small part of sphere receives perpendicular light rays (mainly in areas around equator)

• Most of the sphere receives slanted light rays

• These slanted rays have same energy but got to cover larger area (means less energy per area unit)

• The farther North and South you go, the more slanted the sunlight reaching the surface

Perpendicular rays

Slanted rays

In order to be perpendicular rays, they would have to come from this direction, which does not happen in

this area!

Uneven Heating2. Earth’s axis of rotation is

tilted• Earth does not spin with its axis perpendicular

to the plane of its orbit• Earth’s orbit inclines 23.5 degrees off• Equator does not always receives perpendicular rays from

the sun• Depending on the time of the year, perpendicular sun rays

fall anywhere between the Tropic of Cancer (23.5° north latitude) and Tropic of Capricorn (23.5° south latitude)

• Longest day of the year for each hemisphere is when the sun is directly overhead at the Tropic line

Uneven Heating2. Earth’s axis of rotation is

tilted• The Amount of sunlight falling

on different parts of Earth changes and creates seasons

• When the Earth is tilted with North Pole toward the sun = there is summer in North hemisphere (and winter in South hemisphere)

• When the Earth is tilted with North Pole away from the sun = there is winter in North hemisphere (and summer in South hemisphere)

Uneven Heating3. Earth’s orbit is not circular

• Earth’s orbit is slightly elliptical• Earth gets more heat when its orbit brings it closer to the sun• Earth is closer to the sun during winter in North hemisphere and

farther away from the sun during summer in North hemisphere• This explains why North hemisphere has warmer winters and

cooler summers than South hemisphere

Uneven Heating Biological Importance

• Based on seasons we can predict migratory patterns

• Gray whales annually migrate to Arctic waters to feed off blooming krill and plankton in summer

• In winter gray whales swim south to breed in warmer waters around the Mexican Baja Peninsula

Uneven Heating Convection

• Convection is vertical movement of currents caused by temperature differences in a fluid (like air)

• On Earth, equator is the “kitchen stove” warming up all the Earth’s air and the poles are the cold parts.

• Equator: air heats up and rises, travels towards the poles

• Poles: Air cools down and sinks, and moves back towards equator where it replaces warm air

• Solar energy absorbed by Earth surface causes a general global pattern of winds moving air between equator and poles

• Sun warms up Earth• Earth warms up air in contact

with it• Warm air is less dense and

raises• High above, warm air cools

down and becomes denser (moves down towards the Earth surface)

• Cold air replaces warm air (and cycle continues creating circular pattern)

Coriolis effect Is the tendency for the path of a moving

object to deflect• To the right on the Northern hemisphere• To the left on the Southern hemisphere

Coriolis effect • Explains why we have winds in all directions, not just from north or

south• Effects also the ocean currents• Is major factor affecting the distribution of the Earth’s heat, nutrients

and many types of life• Is caused by Earth’s rotation• Is greater at higher latitudes• Is zero at equator because the rotational velocity does not change

The wind Recall• Convection causes general circulation pattern that moves air

between the equator and the poles• The Coriolis effect deflect air to the right as it travels (to the left in

the southern hemisphere)• This gives the air circular flow pattern rather than a straight north-

south pattern• It is not as simple as above!

• Wind patterns exists in small regions called atmospheric circulation cells

• Atmospheric circulation cells are six distinct air masses (3 in each hemisphere) with individual airflow patterns

The wind – 1. Hadley cells • Most important atmospheric circulation

cell• They lie between the equator and 30

degree north or south latitude• Warm air rises at the equator and moves

northward due to convection• Air does not make it all the way to the

north pole• By the time it reaches 30°N it becomes

dense enough from cooling and moisture loss to sink

• Most of the air descends and flows back to the equator, deflecting to the right (westward) as it flows

• This causes trade winds (flow westward between equator and 30° latitude

• Trade winds are what brought ships to Europe and America centuries ago

The wind – 2. Ferrel cells • Between approximately 30-60

degree latitude• These cells exist because some of

the wind that descends from Hadley cells does not turn toward the equator

• They continue towards the poles shifting to the right or left (depends on the hemisphere)

• The airflow forms the westerlies (because they are from the west) and blows towards the east

• The vertical circulation in Ferrel cells is opposite of what you would expect from convention because it is “sandwiched” between the Hadley cells and the Polar cells

The wind – 3.Polar cells • These lie between approximately 60

degrees and the pole• Airflow in the polar cell is similar to

the Hadley cell• Warm air at 60 degree rises and

flows towards the pole, where it cools, descends, and flows back to the equator

• Coriolis effect deflects it, so that the prevailing polar winds go to the west

• The south –flowing cold air from the polar cells affects the air flowing north and eastward in the Ferrell cells.

• Two air masses do not easily mix due to the different densities and temperatures.

• Polar cell air rises and heads northward again from convection, and causes the Ferrell cell air to deflect upward

INTERTROPICAL CONVERGENCE ZONES• This is where the trade winds meet from both hemispheres

• 30 degrees north and south latitude• Trade winds rise in this region• Vertical movement of air in ITCZ transports large amounts of heat

and moisture• Water vapor condenses in the rising and cooling air, and

rainstorms form.• Some of the world’s wettest climates are in the ITCZ• Surface winds are weak• Sailors call this area doldrums because they could be stranded

there without winds• ITCZ influences climates and weather, and the seasons and

landmasses affect the ITCZ

INTERTROPICAL CONVERGENCE ZONES• This is the reason why there is a difference between the

geographical equator and the meteorological equator (ITCZ)• Geographical equator is 0 degrees latitude• ITCZ is an imaginary line marking the temperature equilibriums

between the hemispheres that shift North and south with seasonal changes.

• It shifts because land has lower heat capacity than water, and there is more land mass in the northern hemisphere.

• Not a straight line due to the landmass affects its location• The ITCZ equator is important because atmospheric circulation is

approximate symmetrical on either side of it• 30 degree latitude leads to high evaporation and little rain fall• Most of the earth’s desert are at this latitude• There is a higher salinity around 30 degree latitude• More water is evaporated that returns to the

ocean making a higher salinity concentration

Monsoons• Seasonal wind pattern changes

caused by heating or cooling on the continents

• Causes summers with significant rainfall and winters with very little

• Results when air warmed by a hot landmass rises

• Warm, moist air from the ocean flows in to replace it; this in turns also rise

• Cools, which causes rain• When winter comes the cycle is

reversed• Wind reverses and land has very

little rain• Common in India and southeast

Asia

Cyclones• Large rotation storm systems of low pressure air

with converging wind at the center• Also called typhoon or hurricanes• Two types: extra tropical and tropical

 

Cyclones - Tropical• From within a single atmospheric cell• Form in low latitudes• Experience explosive growth because

of extremely rapid transport of heat and moisture into the atmosphere from the surface of the warm, tropical ocean

• They quickly dissipate once they hit land due to the loss of heat

• Cyclones move tremendous amounts of heat from the tropics to higher latitudes very quickly

• One cyclone can release about as much energy as the USA uses in an entire year

• This redistribution of heat is important to life on earth

Cyclones - ExtratropicalForm in higher latitudeForms as an area of low air pressure intensifies Occurs between the westbound polar winds and eastbound westerliesThese do not become hurricanes or typhoons They do cause hurricane strength winds, huge ocean waves rain and snow outside the tropics