Chapter 27Section I-II

Moisture in the Atmosphere

Topics for Today• Review

– Water Cycle– Composition and Layers of the Atmosphere– Weather

• New Material– 27-I Humidity

• Humidity– Specific– Relative

• Measuring Humidity– Psychrometer– Hygrometers

– 27-II Condensation Processes• Condensation and Dew Point

– Cooling– Saturation Point– Nuclei

• Fogs – Advective vs. Radiative

Water Cycle

The AtmosphereTemperature, Pressure and Moisture

Weather

• Weather– Weather is the state of atmosphere at a given time and place

– Weather is a combination of… • current temperature • humidity • precipitation• cloudiness • visibility • wind• pressure

Humidity

Specific

RelativeFigure 27.3 pg. 500

Humidity and Quality of Life

Measuring Humidity

• Psychrometer

• Other Hygrometers– Google images– Horse Hair

Condensation

• Cooling to dew point Figure 27.5 pg 503• Condensation on…– surfaces– Nuclei

Condensation at Ground Level: Fog

• Advective

• Radiative

Summary

• Specific Humidity

• Relative Humidity

• Condensation Processes