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