hnrs 227 chapters 17 and 18 - george mason...
TRANSCRIPT
HNRS 227Chapters 17 and 18
Earth’s Air and Oceanspresented by Prof. Geller
1 November 2007
Key Points of Chapter 17
• Atmosphere– winds
• Hydrosphere– evaporation, condensation, humidity
• Weather producers– air masses, weather fronts, waves, cyclones
• Weather forecasting• Climate
Key Points of Chapter 18
• Water on Earth– freshwater, surface water, groundwater,
seawater• Oceans
– waves– currents
Atmosphere
• Composition– Nitrogen (78%), Oxygen (21%), Argon, Water Vapor,
CO2, Methane, other• Atmospheric Pressure
– pressure exerted by atmosphere• Warming
– solar constant– greenhouse effect
• warming due to the transparency of a substance to radiation at visible wavelengths and opacity to infrared radiation
Structure of the Atmosphere
iClicker QuestionThe layers of the atmosphere that are found on
Earth today, in the proper order, from closest to the surface to farthest from the surface are
A mesosphere, thermosphere, troposphere, stratosphere
B stratosphere, mesosphere, thermosphere, troposphere
C troposphere, stratosphere, mesosphere, thermosphere
D troposphere, mesosphere, thermosphere, stratosphere
E thermosphere, mesosphere, troposphere, statosphere
Winds
• Local winds– wind chill
factor• Global wind
patterns
Hydrosphere
• Evaporation• Humidity• Condensation Process
– Clouds, fog– Precipitation
Size of condensationnuclei and droplet
Figure 16.17
Absolute humidity
Figure 16.15
iClicker Question
Without adding or removing any water vapor, a sample of air experiencing an increase in temperature will have
• A a higher relative humidity• B a lower relative humidity• C the same relative humidity• D a changed absolute humidity• E All of the above are possible
Weather Producers
• Air Masses• Fronts• Waves and cyclones• Storms
– thunderstorms, tornadoes, hurricanes
An idealized cold front
Figure 16.25
An idealized warm front
Figure 16.26
A thunderstorm cell
Figure 16.29
Weather Forecasting
• Predictions based upon– “characteristics, location, and rate of
movement of air masses and associated fronts and pressure systems”
• Complex computer models• Led to science of “chaos”
– chaotic dynamic systems
Climate
• “general pattern of the weather that occurs for a region over a number of years”
• Major climate regions– tropical– temperate– polar
The principal climate zones
Figure 16.38
General rainfall patterns
Figure 16.42
Ocean currentsinfluence temperatures
Figure 16.43
Distribution of the Water
The hydrologic cycle
Watersheds of three rivers
The path of groundwater
Oceanography
• Waves and tides– changes coastal structure
• transport of material– long term and short term changes
• Climate control– ocean conveyor belt
• major control of climate
A wave passing in the open ocean
A wave becoming a breaker
Ocean Conveyor Belt -Major Climate Control
iClicker Question
• The average temperature of a location is made more even (temperatures are moderated) by the influence of
• A a large body of water• B elevation• C nearby mountains• D dry air• E None of the above have this effect