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