Composition of the Atmosphere

Meteorology- The study of the entire Meteorology- The study of the entire atmosphere, including its weather.atmosphere, including its weather.

Weather- The daily condition of the Weather- The daily condition of the Earth’s atmosphere. Earth’s atmosphere.

The atmospheric factors that interact The atmospheric factors that interact to cause weather are to cause weather are WindsWinds, , Heat Heat EnergyEnergy, , MoistureMoisture, and , and Air Pressure.Air Pressure.

WindWind

What is the name of the scale that What is the name of the scale that relates wind speed to its effect?relates wind speed to its effect?

Beaufort ScaleBeaufort Scale

Sometimes the temperature will Sometimes the temperature will actually feel colder than it actually is actually feel colder than it actually is due to?due to?

Windchill FactorWindchill Factor

Cont.Cont.

Ex. If the temperature was 25 F and the wind was blowing at 35 mph, the temperature would feel like 7 F and there would be great danger that exposed flesh would freeze

Heat EnergyHeat Energy

• Almost all of Earth’s energy comes from the Sun. This energy is called radiant energy. Even though the Earth only receives about 1/2,000,000,000 of the suns rays, it is enough to keep it warm.

Cont.

• Sun’s energy – Transferred by Radiation

• 30% - reflected back into space by atmosphere or by surface of Earth.

• 19% - absorbed by atmosphere.

• 51% - absorbed by Earth’s surface.

• Some heat is then conducted through the ground thereby heating the lower layer of air.

• Through the process of convection, that lower heated air can then rise as cooler, heavier air takes its place.

• When the sun’s energy reaches Earth, Much of it is converted into infrared or heat rays . Infrared rays cannot pass back out through the atmosphere. It is held in by CO2, Water Vapor, and other gases. This is called the Greenhouse effect because the gases act like the glass that traps in heat in a greenhouse. The burning of fossil fuel is constantly adding CO2 to the air. This causes more infrared rays to be absorbed.

• What could this do to temperatures on Earth? Go up

• What other problems might it cause?-Glaciers could melt, raising sea level and causing flooding; change in rainfall pattern.

Temperature Variations• If the Earth’s atmosphere is warmed by heat rising

from the surface how can air temperature vary so much from place to place?

1. Angle of sun’s rays (seasons)-at equator, rays strike at 90. Since it gets most direct rays it is hotter.

2. Day and night-Obviously there is more direct sunlight during day compared to night.

3. Cloudy and Clear Days-More sun on clear days

4. Type of SurfaceWater heats up slower but cools slower than land.

• Normally, air gets colder with height in the troposphere. In fact, the air usually cools 1 F for every 160 meters up. This constant change is called lapse rate.

• Occasionally, cold air gets caught under a layer of warm air. This upside-down condition is called a temperature inversion

Temperature inversions can cause smoke and other pollutants to get

trapped beneath the warm air. Why do you think this pollution is especially harmful in cities in basins (like Los

Angeles) and beside mountain ranges (like Denver)?

•Because horizontal winds cannot easily carry the polluted air away.

Air Pollution

• Definition:– Any substance in the atmosphere that is

harmful to people, animals, plants, or property.

Main source of air pollution:– Burning of fossil fuels

Pollutants

• Smog- smoke and fog (air pollution + moist air)

• Carbon Monoxide- Colorless, odorless, poisonous gas (from cars)

• Manmade ozone- Nitrogen, oxygen, suns rays.

• Nitrous Oxide- gas produced to put people asleep.

• Hydrocarbons- Produced by burning fossil fuels

Measuring Air Temperature

• Air temperature is measured with:

– Thermometer

– Bimetal Thermometer

– Thermograph – self recording thermometer.