Weather vs. Climate 17.1 Atmosphere Characteristics Weather is constantly changing, and it refers...

Weather vs. Climate

17.1 Atmosphere Characteristics

Weather is constantly changing, and it refers to the state of the atmosphere at any given time and place.

Climate, however, is based on observations of weather that have been collected over many years. Climate helps describe a place or region.

Volume of Clean, Dry Air

What is the most abundant gas in our atmosphere?

What is the second most common gas?

Composition of the Atmosphere


Variable Components Water vapor is the source of all clouds and

precipitation carbon dioxide, water vapor absorbs heat given

off by Earth. It also absorbs some solar energy. Ozone is a form of oxygen that combines three

oxygen atoms into each molecule (O3). ozone filters UV radiation in the stratosphere

allowing life to exist as we know it, In troposphere ozone causes smog

Primary Pollutants

What is responsible for the majority of the primary pollutants?

What is a primary pollutant?

Height and Structure of the Atmosphere


Atmospheric pressure is simply the weight of the air above.

An increase in altitude = decrease in pressure Decreases in pressure =decrease in temperature

Pressure Changes affect temprature

Atmospheric Pressure vs. Altitude

Why does theatmosphere thin (become less dense) with altitude?

What affect does this have on temperature?



Temperature Changes• The atmosphere is divided vertically into four

layers based on temperature change.

• troposphere bottom layer of the atmosphere where temperature decreases with an increase in altitude. Decreased pressure = decreased temp

• stratosphere layer on top of troposphere temperature gradual increase because of O3

Why is the Atmosphere Divided into Layers?

Snowy Mountaintops Contrast with Warmer Snow-Free Lowlands



Temperature Changes• mesosphere the layer above the stratosphere

and is characterized by decreasing temperatures with height, contains no O3

• thermosphere the layer above the mesosphere and is characterized by increasing temperatures due to the absorption of very short-wave solar energy, atoms absorb max energy

Thermal Structure of the Atmosphere

Earth-Sun Relationships


Earth’s Motions• rotation = day and night; revolution = seasons

Why do we have seasons?• Seasonal changes occur because of earths

revolution around the sun and Earth’s axis is tilted to 23.5O

Tilt of Earth’s Axis



Solstices and Equinoxes• summer solstice occurs on June 21 or 22 in the

Northern Hemisphere and is the “official” first day of summer.

• winter solstice occurs on December 21 or 22 in the Northern Hemisphere and is the “official” first day of winter.

During our winter solstice what season is it in Australia?



Solstices and Equinoxes• autumnal equinox (Fall) occurs on September

22 or 23 in the Northern Hemisphere.

• spring equinox (vernal) occurs on March 21 or 22 in the Northern Hemisphere.

How is the length of daylight compared to the length of darkness determined?


is determined by Earth’s position in orbit. Think of the Arctic and Antarctic circle.

• http://esminfo.prenhall.com/science/geoanimations/animations/01_EarthSun_E2.html

Solstices and Equinoxes

Energy Transfer as Heat

17.2 Heating the Atmosphere

Heat energy transferred from one object to another because of a difference in the objects’ temperature.

Temperature a measure of the average kinetic energy a substance, hot more kinetic energy, cold less kinetic energy


What are the three mechanisms of energy transfer as heat?

1. Conduction transfer of heat through solids

2. Convection transfer of heat through fluids

What are insulators? What are conductors?


3. Radiation transfer of energy (heat) through space by electromagnetic waves, can travel through the vacuum of space others can not

6000Co=11000Fo

How does wavelengthRelate to radiant temperature?

Energy Transfer as Heat


Electromagnetic Waves everything that has heat emits these waves. Energy emitted by the sun are part of the electromagnetic spectrum

Are good absorbers also good emitters of radiant energy?

Visible Light Consists of an Array of Colors

Why can you see the spectrum of electromagnetic waves?

Solar Radiation

What Happens to Solar Radiation?

What Happens to Solar Radiation?


• Reflection when light bounces off an object, with same intensity as incident radiation.

• Scattering when light bounces off an object producing a larger number of weaker rays that travel in different directions.


Absorption• 50 percent of the solar energy that strikes the top

of the atmosphere reaches Earth’s surface and is absorbed.

• greenhouse effect heating of Earth’s surface and atmosphere from solar radiation being absorbed and emitted by the atmosphere, two main gasses involved water vapor and carbon dioxide.

Global warming (climate change): the Green House Effect sped up by human activity

What is the Green House Effect? What are the main gases that cause the effect?

What are the main greenhouse gases in troposphere causing global

warming?

What are the 6 things causing Temperatures to vary?

17.3 Temperature Controls

1. Land (low specific heat capacity) heats more rapidly and to higher temperatures, also cools more rapidly and to lower temperatures. Deserts cold at night hot during day

2. Water (high specific heat capacity) heats up slowly and cools down slowly

Mean Monthly Temperatures for Vancouver and Winnipeg

Which is closeto the ocean? What is the effect?

Which is furthest from the ocean?

What is the effect?


3. geographic setting

How does geographic position influence these two cities?


4. altitude

How does altitude influence temperature?


• Albedo is the fraction of total radiation that is reflected by any surface.

5. Cloud cover high albedo therefore reflect back to space a significant portion of suns energy

How does cloud albedo affect these two pictures?

World Distribution of Temperature


Isotherms lines on a weather map that connect points of the same temperature

What do you notice about the isotherms in the north compared to the south?

Weather vs. Climate 17.1 Atmosphere Characteristics Weather is constantly changing, and it refers...

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