Section 4.2 Earth has a variety of climates

Vocabulary  Climate zone: one of the major divisions in a system for classifying the climates of different regions based on characteristics they have in common.  Microclimate: climates of smaller areas within a subclimate.  Urban heat island: a warmer body of air over a city.  Rain shadow: an area on the downwind side of a mountain that gets less precipitation than the side that faces the wind.

Climate Zones  The most widely used climate classification system groups climates by temperature and precipitation.  Six major climate zones include:  Humid tropical  Dry  Moist mid-latitude with mild winters  Moist mid-latitude with severe winters  Polar  highland

Humid Tropical  Tropical Wet: high temperatures throughout the year, humid air causes heavy cloud cover and abundant rainfall and no dry season (annual rainfall is more than 2.5 m). EXAMPLE: Amazon Rain Forest  Tropical Wet & Dry: Hot and rainy but have a dry season in the winter. EXAMPLE: Miami, Florida

Dry  Desert: Precipitation infrequent and scanty (usually less than 20 cm of rain per year), include some of the hottest places on Earth but can be cool (especially at night). EXAMPLE: Phoenix, Arizona  Semiarid: Found next to deserts and have wider temperature ranges than deserts and are not as dry. EXAMPLE: Denver, Colorado

Moist Mid-Latitude with Mild Winters  Humid subtropical: Summers are hot and muggy, winters are usually mild, and precipitation is fairly even throughout the year. EXAMPLE: Charlotte, NC  Marine west coast: Mild temperatures year-round and steady precipitation with low clouds and fog. EXAMPLE: Seattle, Washington  Mediterranean: Dry summers and mild wet winters, some coastal areas have cool summers and frequent fog. EXAMPLE: San Francisco, CA

Moist Mid-Latitude with Severe Winters  Humid continental: Hot summers and cold winters, precipitation fairly even throughout the year, snow covers the ground 1-4 months in winter. EXAMPLE: Des Moines, IOWA  Subarctic: Temperatures usually stay below freezing for 6-8 months, summers brief and cool, low precipitation but snow stays on the ground for long periods of time. EXAMPLE: Fairbanks, Alaska

Polar  Tundra: Average temperature of the warmest month is below 10*c, a deep layer of soil is frozen year-round (permafrost) and turns muddy in the summer as it thaws. EXAMPLE: Barrow, Alaska  Icecap: Surface is permanently covered with ice and snow, temperature rarely rises above freezing. EXAMPLE: Antartica

Highland  Because temperature drops as altitude increases, mountain regions can contain many climates, tall mountains may have year-round covering of ice and snow at their peaks.

Microclimates  Microclimates can be as large as a river valley or smaller than a garden.  Forests, beaches, lakes, valleys, hills, and mountains are some of the features that influence local climates.

Urban Heat Islands  Urban Hot Pocket  Artificial surfaces (concrete, buildings, etc.) have a tendency to absorb more solar energy (radiation) than grass, trees, and soil. Also, these surfaces absorb less water and there is less cooling from evaporation. Lastly, cities use a lot of energy for cooling, transportation, and other activities. This releases heat into the atmosphere.  s

Rain Shadow  Air is forced to rise as it flows over a mountain  As the air rises and cools, it condenses into clouds  Areas that face the wind may receive a lot of precipitation  After passing the mountain, air is much drier because it has lost moisture through condensation and precipitation  MM