Climate and Vegetation

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Chapter 3

• Climate and Vegetation

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• I. Seasons and Weather
• 3 factors cause seasons and control the amount of
  solar energy that falls on different parts of the
  earth
• 1. Rotation
• One complete spin on Earths axis (24 hours)
• Allows for warming and cooling of surface

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• 2. Revolution
• A. 365 ¼ days for Earth to revolve around Sun

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• 3. Tilt
• Axis is tilted 23 ½ degrees

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Combination of revolution and tilt causes
changing seasons

1. Solstice Earths axis points at greatest angle
   towards or away from the sun. It marks the
   beginning of winter/summer.
2. Equinox Latin for equal night occurs when
   axis is not pointed towards or away from the sun.
   It marks the beginning of autumn/spring.

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• B. Weather condition of the atmosphere at a
  particular location time
• Daily weather is complex result of several
  conditions
• Water vapor most is from evaporation of oceans
• W/o water vapor, could be no clouds, rain or
  storms
• Humidity amount of water vapor in air

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• 3. Condensation water vapor changes from gas to
  liquid
• a. seen as fog, clouds or dew
• b. if condensation gets big enough, it falls as
  precipitation

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• b. Elevation
• 1. As elevation (height above sea level)
  increases, the temperature decreases
• 2. Every 1,000 ft. increase in elevation yields
  a 3 ½ degree drop in temp.
• 3. With increased elevation, air becomes thinner
  and loses ability to hold moisture

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• Landforms bodies of water
• Winds move solar energy moisture, resulting
  in rapid weather changes

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• 2. Types of precipitation
• a. Convectional warm, humid air is heated by
  the sun and rises (convection)
• As it rises, the water vapor cools, condenses,
  and falls as precipitation

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• b. orographic
• Moist air from the ocean meets a mountain barrier
  the air is forced to rise
• the windward side of the mountain gets a great
  deal of precipitation
• leeward side of mountain gets a little moisture
  from the warming, descending, dry air

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• c. Frontal
• 1. Front is a boundary between 2 air masses of
  different temperatures and densities

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• 2. Rain/snow occurs when lighter, warm air is
  pushed up over colder, dense, air

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• C. Weather Extremes called storms, occur when
  energy stored in the atmosphere is released
• 1. Hurricanes (aka Typhoons) form over warm
  ocean waters carry violent winds, torrential
  rains, and storm surge (wall of water pushed on
  shore by the wind)
• a. Winds up to 200 mph and storm surges to 20 ft.

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• 2. Tornadoes twisting spiral column of air that
  forms quickly w/o warning
• a. Born from strong thunderstorms
• b. winds may reach 300 mph
• c. US has most tornadoes in the world (avg.
  700/yr and ¾ of all tornadoes occur in the US)

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• 3. Blizzard heavy snow storm w/ winds more than
  35 mph and greatly reduces visibility
• 4. Droughts long period time w/o rain or
  minimal rainfall

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• 5. Floods when water spreads over land not
  normally covered by water

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• II. Climate term for weather conditions at a
  particular location over a long period of time
• 4 major factors influence climate (wind/ocean
  currents, latitude, elevation, topography)
• 1. Air pressure wind the force exerted by air
  is called air pressure

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1. Air pressure creates the winds and ocean currents
   that exchange the globes energy
2. when air is warmed, it expands, becomes lighter,
   and rises (known as convection) thus forming a
   low pressure area. Low pressure tends to bring
   unstable weather

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• C. Cold air is dense, heavy, and tends to sink,
  causing High pressure. High pressure causes
  clear, calm weather

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• 2. Wind is the horizontal motion of air between
  areas of different pressure
• 3. Major Air Pressure zones
• A. Equatorial Low intense heating at the
  equator
• B. Subtropical High around 30 N and S
• C. Sub polar lowabout 60 N and S
• D. Polar High

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• B. Global Warming
• 1. The measurement of heat in Earths atmosphere
  is called temperature.
• 2. The process of heat energy being trapped by
  the atmosphere, keeping Earth warm is called the
  Greenhouse effect.
• 3. CO2 and other heat trapping gases are
  increasing in the atmosphere due to the burning
  of fossil fuels (coal and oil)

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• III. World Climate Regions
• A. Defining a Climate Region
• 1. Most significant factors in defining a climate
  are temperature and precipitation
• 2. Other factors are location on the continent
  (continental or maritime), topography, and
  elevation

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• B. Types of Climates
• 1. Tropical Wet
• avg. temperature 80 F yr. Round more than 80
  in. of rain per year
• 2. Tropical Wet and Dry
• A. rainy season in summer and dry season in
  winter
• B. found next to tropical wet and dry climates

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• 3. Semi Arid
• A. about 16 inches rain/yr
• B. summers are hot and winters are mild
• C. Found in interior of continent or next to
  deserts
• 4. Desert
• A. receive less than 10 in. of rain per year
• B. can be hot or cold most occur around 30
  North or South

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• 5. Mediterranean
• A. summers are hot and dry winters are cool and
  rainy
• B. example land around Mediterranean Sea,
  southern California

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• 6. Marine West Coast
• A. located close to the ocean, foggy, cloudy,
  and damp
• B. Northwest US and Western Europe

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• 7. Humid Sub Tropical
• A. Long hot summer and humidity, mild to cool
  winters
• B. Southeast US and east coast of continents

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• 8. Humid Continental
• A. great variety of temperatures and
  precipitation
• B. 4 distinct seasons located in mid-latitude
  interior of Northern Hemisphere continents

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• 9. Sub Arctic
• A. evergreen forests called tiaga cover sub
  arctic areas
• B. greatest temperature differences from winter
  to summer of all climates
• C. short, cool summers, winter, very cold
  below freezing for 5 8 months of yr

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• 10. Tundra
• A. flat, treeless land around Arctic circle
• B. less than 15 inches of rain/yr summer lasts
  only a couple of weeks temps. Only reach 40F.
• C. has permafrost, subsoil is constantly frozen
  year round

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• 11. Ice Cap
• A. snow, ice, permanently freezing temperatures

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• 12.Highland
• A. Climate varies with latitude, elevation, etc.
  In Mountainous areas depends on if a slope faces
  north or south, cold winters, warm summers. Ex.
  Rocky Mts.

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• IV. Soils and Vegetation
• A. Vegetation Regions
• 1. Ecosystem-interdependent community of plants
  and animals

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• 2. Biome the ecosystem of a region
• A. forest
• 1. Deciduous, coniferous, or mixed
• 2. Almost exclusively in N. Hemisphere

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• B. Grassland mostly flat land dotted with few
  trees
• 1. In tropical areas, often called a savanna
• 2. In N. Hemisphere, called steppe or prairie
  S. America called a pampas

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• c. Desert
• 1. Plants that can conserve water and withstand
  heat

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• d. Tundra
• 1. Only plants such as lichens and moss can
  survive the cold, dry climate