Date post: | 31-Dec-2015 |
Category: |
Documents |
Upload: | alice-thornton |
View: | 215 times |
Download: | 1 times |
The Atmosphere: Structure and Temperature
How Does Weather differ from Climate?
Weather : constantly changing and it refers to the state of the atmosphere at any given time and place
Climate – is based on observations of weather that have been collected over many years
1. Air temperature2. Humidity3. Type/Amount of Precipitation4. Air Pressure5. Speed/Direction of Wind
Measurable Properties of Weather and Climate
Composition of the Atmosphere Major
Components: Air – a mixture of
different gases and particles
Nitrogen and Oxygen makeup 99%
1 % is argon Carbon dioxide is
present in small amounts but is an active absorber of energy so plays a role in heating.
Variable Components: Water Vapor
Water vapor - source of all clouds and precipitation.
Absorbs heat and some solar energy
Movements of the atmosphere allow solid and liquid particles to be suspended within it
Large Particles are too heavy to stay in the air for too long
Microscopic remain suspended for longer
Examples: smoke, pollen
Dust Particles
Ozone Not distributed evenly Absorbs Potential
harmful UV radiation by the sun
Without it our habitat would be uninhabitable
Human Influences and Primary Pollutants
Primary Pollution: emitted directly from identifiable sources
Transportation counts for half
Secondary Pollutions: not emitted directly into air (agriculture)
Can be caused by reactions
Primary Pollutants and
Sources Primary Pollutants Carbon
monoxides Nitrogen oxides Volatile Organics Sulfur oxides Particulate
matter
Sources Transportation Stationary
Source Fuel Combustion
Industrial Processes
Solid Waste
Pressure and Temperature
Changes Key Point: The atmosphere
rapidly thins as you travel away from Earth until there are too few gas molecules to detect.
Pressure Changes Atmospheric pressure is the
weight of the air above. As you go up in altitude (or travel
away from Earth) pressure decreases
Layers of the Atmosphere The Troposphere - the
bottom layer Temperature decreases with an
increase in altitude. Where weather occurs Tropopause: boundary of the
troposphere The Stratosphere
Above the troposphere Temperature remains constant,
then gradually starts to increase Contains the ozone layer Stratopause: boundary of the
stratosphere
The Mesosphere Temperature decreases with
height Mesopause: boundary of the
mesosphere The Thermosphere:
Upper layer Temperature increase with
height Auroras occur here Fades into space
Energy that drives the weather and climate come from the sun
Solar energy is NOT distributed evenly
Varies with latitude, time of day, and season of the year
Unequal heating of the Earth creates wind’s and drives the ocean’s currents
Results in weather
Earth-Sun Relationships
Earth’s Motion Rotation: spinning of
the Earth about its axis (24 hours)
Revolution : movement of Earth in its orbit around the sun (365.25 days)
Key Point: Seasonal changes occur because Earth’s position relative to the sun continually changes as it travels along its orbit.
Tilted 23.5 from perpendicular
Rotation and Revolution
What causes Seasons?
NOT IN NOTES
Seasons are caused by the tilting of the earth on its axis When the Earth is
tilted towards the Sun – warmer seasons
When the Earth is tilted away from the Sun – cooler seasons
Summer Solstice: June 21 or 22 First day of summer “leaning” 23.5˚ towards the
sun or Tropic of Cancer
Winter Solstice: December 21 or 22 “leans” 23.5 away or Tropic
of Capricorn
Equinox
Autumnal Equinox September 22 or 23 First day of fall
Spring Equinox March 21 or 22 First day of spring
Sun rays directly over the equator
Daylight and nighttime length are the same
Heating the Atmosphere Heat: the energy
transferred from one object to another because of a direct difference in their temperature
Temperature: measure of the amount of heat
Ways Heat Can be Transferred
Key Point: Heat is the energy transferred from one object to another because of a difference in their temperatures.
Conduction The transfer of heat through
matter by molecular activity Transfer by touching Collisions
Convection The transfer of heat
by a mass movement or circulation
Fluids Radiation
Travels out in all directions
Doesn’t need matter
Three Results:1. Some energy is absorbed, causing
temp to increase.2. Water and air are transparent to
certain wavelengths (goes through)3. Some bounces off
What happens to solar radiation?
What Happens to Solar Radiation?
Reflection bounces off 30 % is reflected back
to space Scattering
Disperses light so travels in many directions.
Absorption:
50 % of the solar energy the Earth’s surface
20% is absorbed in the clouds
Greenhouse effect: heating of Earth from radiation being absorbed
Why Do Temperatures Vary?
A temperature control is any factor that causes temperature to vary from place to place and time to time.
Factors: Heating of land Heating of water Altitude Geographic
position Cloud cover Ocean currents
Land and Water Temperatures
Land heats and cools more rapidly and to higher temperatures than water. Land also cools more rapidly and to a lower temperature than water.
Windward verses Leeward
Windward: Winds blow from
ocean to shore, so wetter
Leeward: Winds blow from land
toward ocean, so dry
Mountains act as barriers
Altitude Higher altitudes
have cooler temperatures.
Albedo the fraction of total
radiation that is reflected by any surface.
Key Point: many clouds have high albedo and reflect the sunlight back to space.
World Distribution and Temperatures
Isotherms - lines on a weather map that connect points that have the same temperatures
Hot colors near equator , cool colors toward the poles
Pg. 4821. When do the sun’s rays strike 23.5?2. When does summer solstice occur in the northern
hemisphere?3. When is the autumnal equinox occur in the southern
hemisphere?
Pg. 4901. Is Eureka or NYC the leeward city?2. Which city has temperatures that are influences by
ocean winds AND has cool summers and mild winters?
Pg. 4921. What does cloud cover do to the day time
temperatures?2. What does cloud cover do to the nighttime
temperatures?
Picture and Graph Questions