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Introduction to
Geography
Arthur Getis, Judith Getis, &
Jerome D. Fellmann
Physical Geography:
Weather & Climate
Chapter 4
Overview
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Air Temperature
Air Pressure & Winds
Ocean Currents
Moisture in the Atmosphere
Climate
Climate Regions
Climate Change
Air Temperature
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Solar energy
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Insolation
Sun angle
Number of daylight hours
Amount of water vapor
Cloud cover
Land vs. water
Elevation above sea level
Degree & direction of air movement
Earth inclination
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Axis of the earth tilts at ≈ 23.5°
Rotation once every 24 hours
21 June / summer solstice
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21 December / winter solstice
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Vertical rays of the sun at 23.5 ° N
 Tropic of Cancer
Northern hemisphere tilted towards the sun
Vertical rays of the sun at 23.5 ° S
 Tropic of Cancer
Equinoxes on March 21 & September 21
Reflection & Reradiation
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Clouds & light surfaces reflect energy
Reradiation also contributes to lost energy
Water stores more energy than land
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Land heats & cools more rapidly
Water heats & cools more slowly
The Lapse Rate
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6.4°C per 1000 meters
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3.5°F per 1000 feet
Temperature inversions
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Cooler air trapped below warmer air
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Can contribute to smog problems
Air Pressure & Winds
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Air pressure is higher near the earth’s surface
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Pressure measured by a barometer
Pressure gradient forces air to blow from high
to low pressure areas
Convection
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Warm air rises
Cool air sinks
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Land & sea breezes
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Mountain & valley breezes
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Warmer air over land replaced by cooler air
over water
Cooler air in mountains sinks into valley
(often at night)
Warmer air in valleys rises into mountains
(often during the day)
Coriolis effect
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Wind veers towards the right in the Northern
Hemisphere and to the left in the Southern
Hemisphere
Global Air-Circulation Pattern
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Equatorial low pressure
Northeast trades
Westerlies
Subpolar low
Polar easterlies
Polar high
Ocean Currents
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Roughly corresponds to global wind direction
patterns
Differences in water density also cause
movement
Coriolis effect
Landmasses are a barrier to currents
Moisture in the Atmosphere
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Precipitation
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Rain, sleet, snow, or hail
Supersaturation leads to droplets if condensation
nuclei are present
Relative humidity
Types of Precipitation
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Convectional precipitation
Orographic precipitation
Cyclonic, or frontal precipitation
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Air masses
Storms
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Midlatitude cyclones
Hurricanes
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Typhoons
Blizzards
Tornadoes
Climate
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A generalization based on daily & seasonal
weather conditions
Soil Formation
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Geology
Climate
Topography
Biology
Time
Soil Horizons
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O-horizon
A-horizon
E-horizon
B-horizon
C-horizon
R-horizon
Soil Properties
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Composition
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Texture
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Proportion of sand, silt, & clay
Structure
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Organic & inorganic
Size, shape, and alignments of clumps
Nutrients
Acidity or alkalinity
Natural Vegetation
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Succession
Natural Vegetation Regions
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Tropical rain forest
Mediterranean or chaparral
Semidesert
Desert
Prairie / steppe
Deciduous woodlands
Coniferous woodlands
Tundra
Climate Classification
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Köppen Climate Types
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A
B
C
D
E
H
Tropical Climates (A)
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Tropical Rain Forest (Af)
Savanna (Aw,Am)
Dryland Climates
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Hot Deserts (BWh)
Midlatitude Deserts & Semideserts (BWk,
BS)
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Steppe
Humid Midlatitude Climates
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Mediterranean (Cs)
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Cold, wet winters & dry, hot summers
Humid Subtropical (Cfa)
Marine West Coast (Cfb)
Humid Continental (Dfa,Dfb)
Subarctic & Arctic Climates
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E
Tundra
Climate Change
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Long cycles
Quicker changes
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Small changes in upper-air wind movements
Volcanic eruptions
Human activity