Air Temperature MeasurementAir Temperature Measurement

• Thermometer Types– Liquid-in-glass– Bimetallic– Electrical

• Proper Site Selection– Height above ground– Shaded– Ventilated

Temperature Change with Temperature Change with ElevationElevation

• Generally decreases with increasing elevation in the troposphere

• Vertical Temperature Profile- Atmosphere

• Importance of elevation of surroundings– Denver vs. State College– Denver vs. WV mountains

Seasonality

• Temperature difference between warm and cold season

• Generally greater over land than water• Generally increases with distance from water

– Heat capacity difference– Penetration of solar radiation in water– Mixing and currents in water– Evaporation of water

• Cloud cover amount

Prevailing Wind DirectionPrevailing Wind Direction

• Blowing from water or land?– Charleston, SC vs. San Diego, CA

Ocean CurrentsOcean Currents

• Water temperature– Cold currents on west coasts, in general– Warm currents on east coasts, in general

Air MassesAir Masses

• A large volume of air (thousands of miles across by several miles deep) with similar temperature and moisture characteristics throughout

• Source Regions = High Pressure Areas– Air acquires attributes of underlying surface– Continental vs. Maritime (moisture)– Polar vs. Tropical (temperature)

Key FiguresKey Figures

• 3.1, 3.2, 3.10, 3.17, 3.20, 3.38