Introduction to Geography Arthur Getis, Judith Getis, & Jerome D. Fellmann

Physical Geography: Weather & Climate Chapter 4

Overview Air Temperature Air Pressure & Winds Ocean Currents Moisture in the Atmosphere Climate Climate Regions Climate Change

Air Temperature Solar energy 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 Axis of the earth tilts at ≈ 23.5° Rotation once every 24 hours 21 June / summer solstice Vertical rays of the sun at 23.5 ° N Tropic of Cancer Northern hemisphere tilted towards the sun 21 December / winter solstice Vertical rays of the sun at 23.5 ° S Tropic of Cancer Equinoxes on March 21 & September 21

Reflection & Reradiation Clouds & light surfaces reflect energy Reradiation also contributes to lost energy Water stores more energy than land Land heats & cools more rapidly Water heats & cools more slowly

The Lapse Rate 6.4°C per 1000 meters 3.5°F per 1000 feet Temperature inversions Cooler air trapped below warmer air Can contribute to smog problems

Air Pressure & Winds Air pressure is higher near the earth’s surface Pressure measured by a barometer Pressure gradient forces air to blow from high to low pressure areas Convection Warm air rises Cool air sinks

Land & sea breezes Warmer air over land replaced by cooler air over water Mountain & valley breezes Cooler air in mountains sinks into valley (often at night) Warmer air in valleys rises into mountains (often during the day) Coriolis effect Wind veers towards the right in the Northern Hemisphere and to the left in the Southern Hemisphere

Global Air-Circulation Pattern Equatorial low pressure Northeast trades Westerlies Subpolar low Polar easterlies Polar high

Ocean Currents 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 Precipitation Rain, sleet, snow, or hail Supersaturation leads to droplets if condensation nuclei are present Relative humidity

Types of Precipitation Convectional precipitation Orographic precipitation Cyclonic, or frontal precipitation Air masses

Storms Midlatitude cyclones Hurricanes Typhoons Blizzards Tornadoes

Climate A generalization based on daily & seasonal weather conditions

Soil Formation Geology Climate Topography Biology Time

Soil Horizons O-horizon A-horizon E-horizon B-horizon C-horizon R-horizon

Soil Properties Composition Organic & inorganic Texture Proportion of sand, silt, & clay Structure Size, shape, and alignments of clumps Nutrients Acidity or alkalinity

Natural Vegetation Succession Natural Vegetation Regions Tropical rain forest Mediterranean or chaparral Semidesert Desert Prairie / steppe Deciduous woodlands Coniferous woodlands Tundra

Climate Classification Köppen Climate Types A B C D E H

Tropical Climates (A) Tropical Rain Forest (Af) Savanna (Aw,Am)

Dryland Climates Hot Deserts (BWh) Midlatitude Deserts & Semideserts (BWk, BS) Steppe

Humid Midlatitude Climates Mediterranean (Cs) Cold, wet winters & dry, hot summers Humid Subtropical (Cfa) Marine West Coast (Cfb) Humid Continental (Dfa,Dfb)

Subarctic & Arctic Climates E Tundra

Climate Change Long cycles Quicker changes Small changes in upper-air wind movements Volcanic eruptions Human activity