Structure and Temperature THE ATMOSPHERE. ATMOSPHERE CHARACTERISTICS Most important measurable...
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Transcript of Structure and Temperature THE ATMOSPHERE. ATMOSPHERE CHARACTERISTICS Most important measurable...
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• 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
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
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
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
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
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
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
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.