HNRS 227 Lecture #20 Chapter 16 Earth’s Weather presented by Prof. Geller 4 November 2003

Key Points of Chapter 16 zAtmosphere ywinds zHydrosphere yevaporation, condensation, humidity zWeather producers yair masses, weather fronts, waves, cyclones zWeather forecasting zClimate

Atmosphere zComposition yNitrogen (78%), Oxygen (21%), Argon, Water Vapor, CO 2, Methane, other zAtmospheric Pressure ypressure exerted by atmosphere zWarming ysolar constant ygreenhouse effect xwarming due to the transparency of a substance to radiation at visible wavelengths and opacity to infrared radiation

Structure of the Atmosphere

Winds zLocal winds ywind chill factor zGlobal wind patterns

Hydrosphere zEvaporation zHumidity zCondensation Process yClouds, fog yPrecipitation

Size of condensation nuclei and droplet Figure 16.17

Absolute humidity Figure 16.15

Weather Producers zAir Masses zFronts zWaves and cyclones zStorms ythunderstorms, tornadoes, hurricanes

An idealized cold front Figure 16.25

An idealized warm front Figure 16.26

A thunderstorm cell Figure 16.29

Weather Forecasting zPredictions based upon y“characteristics, location, and rate of movement of air masses and associated fronts and pressure systems” zComplex computer models zLed to science of “chaos” ychaotic dynamic systems

Climate z“general pattern of the weather that occurs for a region over a number of years” zMajor climate regions ytropical ytemperate ypolar

The principal climate zones Figure 16.38

General rainfall patterns Figure 16.42

Ocean currents influence temperatures Figure 16.43