Chapter 1 Introduction to the Atmosphere The Atmosphere 9e Lutgens & Tarbuck Power Point by Michael C. LoPresto

1. Chapter 1Introduction to the AtmosphereThe Atmosphere 9eLutgens & TarbuckPower Point by Michael C. LoPresto

2. Weather and Climate • Weather is the state of the atmosphere at any given time. • Climate – a description of aggregate weather conditions; the sum of all statistical weather information that helps describe a place or region.

3. Weather is constantly changing (hour by hour, day by day) • Climate based on observations over many decades

4. Basic Elementsof Weather & Climate • The most important elements are • (1) air temperature, • (2) humidity, • (3) type and amount of cloudiness, • (4) type and amount of precipitation, • (5) air pressure, and • (6) the speed and direction of the wind

5. Earth's four spheres include: • the atmosphere (gaseous envelope), • the lithosphere (solid Earth), • the hydrosphere (water portion), • and the biosphere (life). • Each sphere is composed of many interrelated parts and is intertwined with all other spheres.

6. Lithosphere • Core • Mantle • Crust • Atmosphere • 99% of atmosphere within 30 km of Earth’s surface. • Provide air we breathe and protects from UV

7. Hydrosphere • Water is what makes planet Earth unique • Global Ocean • 71% of Earth’s surface • 97% of Earth’s water • Biosphere • Involves all life on Earth

9. The Atmosphere:A Part of the Earth System

10. Systems • Closed • Energy moves in/out, but matter cannot • Open • Both energy/matter move in/out • Negative Feedback • Keep status quo • Positive Feedback • Drive for change

11. The Atmosphere • The life-giving, gaseous envelope that surrounds the Earth. • energy exchanges between the atmosphere and Earth’s surface along with space produces weather.

12. Air is a mixture of many gases, and its composition varies • Two gases, nitrogen (78%) and oxygen (21%), make up 99 percent of the volume of the remaining clean, dry air.

13. Composition of the Atmosphere

15. Carbon Dioxide - present in small amounts, it is very important to meteorology. • Absorbs energy and leads to a rise in global temperature (Greenhouse Effect)

16. Carbon Dioxide

17. Variable Components • Water vapor - absorbs heat given off by Earth as well as some solar energy. • When water vapor changes from one state to another, it absorbs or releases heat. • In the atmosphere, water vapor transports this latent ("hidden") heat from one region to another, and it is the energy source that helps drive many storms.

18. Aerosols act as surfaces on which water can condense • absorbers and reflectors of incoming solar radiation. • Ozone (O3) • Concentrated in the stratosphere • Absorbs potentially harmful UV rays from the sun.

19. Ozone Depletion

20. Ozone

22. Formation of Ozone

23. Sustaining Ozone

24. Depletion of Ozone

25. Thermal Structure of the Atmosphere • The atmosphere is divided vertically into four layers on the basis of temperature • Troposphere • Stratosphere • Mesosphere • Thermosphere

26. Troposphere • Layer in which we live, where nearly all weather occurs • Temperature decreases with an increase in altitude • Environmental lapse rate – name given to the temp. decrease • (normal lapse rate- 6.5o per kilometer)

27. The ELR is not constant it can change day to day • In some shallow layers the temp will increase, temperature inversion. • Near the equator, thermal mixing creates thicker layers for the troposphere • Closer to the poles, the troposphere is thinner

28. Stratosphere • The boundary between the stratosphere and troposphere is called the tropopause • Temperatures rise through the atmosphere • This is due to ozone absorbing UV rays • Although the ozone is thinner at top of strat., it absorbs enough energy to keep the warmer temp

29. Mesosphere • Stratopause marks the end of the stratosphere • Temp begins to decrease with height at mesopause • The coldest temps in the atmosphere occur in the mesosphere

30. Thermosphere • The mesopause marks the end of the mesosphere and the beginning of the thermosphere • No well-defined upper limit • Although the temp is hot, it would not feel hot because there are very few air molecules

31. Ionosphere • Lower portion of the thermosphere • Here molecules of nitrogen and oxygen are ionized • Electrons are then free to travel as electric current • The aurora borealis and aurora australis are found here

32. Structure of the Atmosphere Thermal Structure

33. Pressure Decreases with Altitude

35. Chapter 1 END