Structure and Temperature

THE ATMOSPHERE

ATMOSPHERE CHARACTERISTICS• Most important measurable properties

• Air Temperature

• Humidity

• Type of Precipitation

• Amount of Precipitation

• Air Pressure

• Speed of Wind

• Direction of Wind

WEATHER VS CLIMATE• Weather• Conditions of the atmosphere at a given

time and place• The day to day changes

• Climate• Observations of weather that have been

collected over many years• Describes a place or region

COMPOSITION OF THE ATMOSPHERE

• Wasn’t always like it is now• 4.6 billion years ago was made of

gases from volcanic eruptions• Oxygen started gathering around 2.5

billion years ago• Continuously exchanges material with

oceans and plant life

MAJOR COMPONENTS OF ATMOSPHERE• Varies from time to time and place to place• 99% Nitrogen and Oxygen• .93% Argon• .039% CO2

VARIABLE COMPONENTS

• 1. Water Vapor•Source of all clouds and

precipitation•Absorbs heat given off by Earth•Absorbs solar energy

VARIABLE COMPONENTS• 2. Dust Particles

• Large particles don’t stay in the air for long

• Microscopic particles travel for miles

• Sea salts from breaking waves

• Fine soil blown into air

• Smoke and soot from fires

• Pollen and other microorganisms

• Ash and dust from volcanic eruptions

VARIABLE COMPONENTS

• 3. Ozone (O3)

• Concentrated in layer 10-50km above Earth’s surface

• Near earth we have O2, but when it rises it absorbs UV radiation and splits into O

• Ozone formed when single O atoms collide with O2 atoms

• Ozone layer important to us

• Blocks UV rays

HUMAN INFLUENCE• Primary Pollutants• Emitted directly from identifiable source

HUMAN INFLUENCE• Secondary Pollutants

• Not emitted directly in air

• Form when primary pollutants mix in atmosphere

• Sulfur dioxide enters atmosphere

• Reacts with oxygen gas

• Produces Sulfur Trioxide

• Combines with water to produce acid rain

HUMAN INFLUENCE• Secondary Pollutants

• Not emitted directly in air

• Photochemical reactions

• Nitrogen oxides absorb solar radiation

• Produces irritating, toxic volatile organic compounds

• Known as photochemical smog

PRESSURE CHANGES IN ATMOSPHERE• The higher you go the

less air there is to push

down on you

TEMPERATURE CHANGES IN ATMOSPHERE• What does this picture show us about

temperature changes?

LAYERS OF THE ATMOSPHERE• 1. Troposphere• Tropopause

• 2. Stratosphere• Stratopause

• 3. Mesosphere• Mesopause

• 4. Thermosphere

LAYERS OF THE ATMOSPHERE• 1. Troposphere• Temperature decreases with altitude• All weather occurs here• Made of 99% nitrogen, oxygen, argon

and carbon dioxide• Most dense at surface of Earth•Decreases with altitude

LAYERS OF THE ATMOSPHERE

• 2. Stratosphere• Temperature is constant up to 20km then

increases (ozone layer)• No wind so air is calm• 19% Atmospheric gases – the rest is

ozone• Density is very thin

LAYERS OF THE ATMOSPHERE• 3. Mesosphere• Temperature decreases with height• Nitrogen and Oxygen levels are the

same as troposphere• There is very little movement but still

dense enough to stop meteors

LAYERS OF THE ATMOSPHERE• 4. Thermosphere• Temperatures increase because solar radiation

is being absorbed• Very thin•Molecules can travel for miles before hitting

one another• We can’t really describe its chemical

composition because there are hardly any molecules here

LAYERS OF THE ATMOSPHERE

EARTH-SUN RELATIONSHIPS• All energy for Earth’s weather and climate

comes from sun

• Earth absorbs less than one two-billionth of energy given off by sun

• Still several hundred thousand times more than we need

• Sun doesn’t heat everywhere on Earth evenly

• Unequal heating causes wind and ocean currents

EARTH’S MOTIONS• Rotation• Spinning on axis• Happens every 24 hours

• Revolution• Orbit around sun• Happens every year• Earth travels 113,000km/hr

EARTH’S ORIENTATION• Why is it colder in the winter and warmer in the

summer?

• Seasonal changes happen

because of the tilt of the

Earth’s axis

• Earth is tilted at 23.50 from

perpendicular

• Axis always pointed

toward North Star

SUN’S APPARENT PATH

• Varies with latitude and season• Angle of noon sun can vary up to 47

degrees in our location• In June when we are pointed toward the

sun the rays hit us at a 73.5 degree angle• In December when we are pointed away it

hits at a 26.5 degree angle

THE SEASONS AND LENGTH OF DAY

SECTION ONE REVIEW• Compare and contrast weather and climate.

• Why do seasonal changes occur?

• How much of the Earth’s atmosphere is located below 5.6 kilometers?

• How do ozone molecules form?

• In which layers of the atmosphere does temperature increase with increasing height?

• Explain what would happen to air temperatures in the troposphere if carbon dioxide were removed from air.

HEATING THE ATMOSPHERE• Heat and temperature are two different things

• Heat is the energy transferred from one object to another because of a difference in their temperatures

• Temperature is a measure of the average kinetic energy of the atoms or molecules of a substance

• If energy is added to molecules they move faster and the temperature increases

WAYS TO TRANSFER ENERGY• 1. Conduction• Transfer of heat through matter by

molecular activity• Molecules are close to one another

and when one gets excited it hits the one next to it which also gets excited• Like a metal spoon in a hot pot• Air is really poor conductor

WAYS TO TRANSFER ENERGY• 2. Convection• Transfer of heat by mass movement or

circulation within a substance• Like a lava lamp or hot air balloon• Sun warms objects, air around those

objects gets heated by conduction then warm air rises

WAYS TO TRANSFER ENERGY• 3. Radiation

• Travels through vacuum of space

• All objects, no matter what their temperature, emit radiant energy

• Hotter objects radiate more total energy than colder objects

• The hottest radiating bodies produce the shortest wavelengths

• Objects that are good absorbers of radiation are good emitters too

• Atmosphere doesn’t absorb all wavelengths-some get through

WAYS TO TRANSFER ENERGY

ELECTROMAGNETIC WAVES• These waves move at 300,000km/second through

space

• Our atmosphere doesn’t slow them down too much

• Waves move out from source like a pebble hitting water

ELECTROMAGNETIC WAVES

RAINBOW IS ALWAYS IN SAME ORDER AS ELECTROMAGNETIC SPECTRUMDOUBLE RAINBOW IS REVERSED

WHAT HAPPENS TO RADIATION?

• 1. Absorbed• Energy added and temperature

increases• 2. Transmitted• Energy passes through

• 3. Reflected• Energy bounces off object

WHAT HAPPENS TO RADIATION?

REFLECTION AND SCATTERING• Reflection

• Wave bounces off

object with same intensity

that it hit object

• Scattering

• Wave split into large

number of weaker waves

SO WHY IS THE SKY BLUE?• The air is full of small dust and gas particles

• Light gets scattered in all directions

• This is how light reaches underneath a shade tree

• Blue has a very short wavelength compared to other colors

• It gets scattered the most

• Sunrise and Sunset are red/orange because of the angle we see them

• They have to pass through a lot of particles

• Red and orange are long wavelengths and everything else gets scattered away

ABSORPTION• Water vapor and carbon dioxide are good absorbers

• When they absorb energy their temperature rises

• Known as Greenhouse Effect

• This is actually a good thing

• We’d be really cold without it

• Different from Global Warming

• This increase is caused or influenced by human activities

PHOTOSYNTHESIS• Small amount of energy not absorbed and then

reradiated

• Chlorophyll in plants absorb this energy and use it to make their own type of energy

• So the sun is the main source for all energy on Earth

SECTION 2 REVIEW• How are heat and temperature related?

• What are the three ways heat is transferred?

• What three things happen when solar radiation strikes an object?

• How are scattering and reflection different?

• Dark objects tend to absorb more radiation than light-colored objects. Explain whether dark objects or light objects on Earth’s surface would be better radiators of heat.

TEMPERATURE CONTROLS• Any factor that causes temperature to vary from

place to place and time to time

• Latitude

• Differential heating of land and water

• Altitude

• Geographic position

• Cloud cover

• Ocean currents

LAND AND WATER• Lands heats more

rapidly but also cools

off more rapidly

• Cities near water

have less

temperature

variations

LAND AND WATER• Northern hemisphere

• 61% land

• 39% water

• Southern hemisphere

• 19% land

• 81% water

GEOGRAPHIC POSITION• Windward coast

• Wind blows from

ocean onto shore

• Leeward coast

• Wind blows from

land out to ocean

GEOGRAPHIC POSITION

• Mountains can

get in the way

• Reduces effect

of windward location

ALTITUDE• Guayaquil

• 12m above

sea level

• Quito

• 2800 m above

sea level

CLOUD COVER AND ALBEDO• Albedo

• Fraction of total radiation reflected by any surface

• Clouds have high albedo

• So does snow

• During the day you want clouds to reflect sun away and keep you cool

• At night you want clouds to reflect Earth’s heat back upon itself to keep you warm

CLOUD COVER AND ALBEDO

WORLD DISTRIBUTION OF TEMPERATURE• Isotherms

• Connect points of equal temperature

• Look at World Isotherm Map on page 493

• What effect does latitude have on temperature?

• What effect does the distribution of land and water have on temperature?

• Estimate the latitude range for temperatures between 20 and 25 degrees Celsius in the Northern Hemisphere.

• Do you expect the color of the temperature band to change near the equator for the month of January? Explain your prediction.

SECTION 3 REVIEW• What is a temperature control?

• How do the heating of land and water differ?

• Why is it cooler on a cloudy day? What happens to the radiation from the sun on these days?

• Why do some coastal cities experience a moderation of temperature from water, while others do not?