17 1 Atmosphere Characteristics Weather vs Climate Weather

17. 1 Atmosphere Characteristics Weather vs. Climate 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?

17. 1 Atmosphere Characteristics 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 (O 3). © ozone filters UV radiation in the stratosphere allowing life to exist as we know it, © In troposphere ozone causes smog

Primary Pollutants What is a primary pollutant? What is responsible for the majority of the primary pollutants?

17. 1 Atmosphere Characteristics Height and Structure of the Atmosphere Pressure Changes affect temprature © Atmospheric pressure is simply the weight of the air above. © An increase in altitude = decrease in pressure © Decreases in pressure =decrease in temperature

Atmospheric Pressure vs. Altitude Why does the atmosphere thin (become less dense) with altitude? What affect does this have on temperature?

17. 1 Atmosphere Characteristics Height and Structure of the Atmosphere Temperature Changes Why is the • The atmosphere is divided vertically into four layers Atmosphere based on temperature change. Divided into • troposphere bottom layer of the atmosphere Layers? where temperature decreases with an increase in altitude. Decreased pressure = decreased temp • stratosphere layer on top of troposphere temperature gradual increase because of O 3

Snowy Mountaintops Contrast with Warmer Snow-Free Lowlands

17. 1 Atmosphere Characteristics Height and Structure of the Atmosphere Temperature Changes • mesosphere the layer above the stratosphere and is characterized by decreasing temperatures with height, contains no O 3 • 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

17. 1 Atmosphere Characteristics 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. 5 O

Tilt of Earth’s Axis

17. 1 Atmosphere Characteristics Earth-Sun Relationships 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?

17. 1 Atmosphere Characteristics Earth-Sun Relationships 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.

17. 1 Atmosphere Characteristics 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/01_Earth. Sun_E 2. html

Solstices and Equinoxes

17. 2 Heating the Atmosphere Energy Transfer as 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

17. 2 Heating the Atmosphere What are three mechanisms of energy transfer as heat? 1. Conduction transfer of heat through solids What are insulators? What are conductors? 2. Convection transfer of heat through fluids

17. 2 Heating the Atmosphere 3. Radiation transfer of energy (heat) through space by electromagnetic waves, can travel through the vacuum of space others can not How does wavelength Relate to radiant temperature? 6000 Co=11000 Fo

Energy Transfer as Heat

17. 2 Heating the Atmosphere 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?

17. 2 Heating the Atmosphere 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.

17. 2 Heating the Atmosphere 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 are the main greenhouse gases in troposphere causing global warming? What is the Green House Effect? What are the main gases that cause the effect?

17. 3 Temperature Controls What are the 6 things causing Temperatures to vary? 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 close to the ocean? What is the effect? Which is furthest from the ocean? What is the effect?

17. 3 Temperature Controls 3. geographic setting How does geographic position influence these two cities?

17. 3 Temperature Controls 4. altitude How does altitude influence temperature?

17. 3 Temperature Controls 5. Cloud cover high albedo therefore reflect back to space a significant portion of suns energy • Albedo is the fraction of total radiation that is reflected by any surface. How does cloud albedo affect these two pictures?

17. 3 Temperature Controls 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?