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					    Climate
Ch. 26 (Climate) &
 Ch.15 (Ice Ages)
               Climate
• Climate: average
  –ppt- Avg month & year
  –Temp- Avg high and low
     • Temp range
  –Factors that influence climate:
     • Latitude (Winds, Ocean Currents)
     • Heat absorption and release
     • Topography
          Koppen Climates
    NO, you don’t have to memorize
                these!
•   A: tropical
•   B: deserts
•   C: temperate
•   D: severe
•   E: polar
•   H: highlands
•   Upper case designates LATITUDE
•   Temperature (lower case): a=hot, b=cool,
    c=cold summer
• Precipitation (lower case) s=summer
  drought, w=winter drought, f=wet year
  round, m=monsoon
• Examples: Tropical Rainforest (Af)
  – Tropical Monsoon (Am)
  – Tropical Savanna (Aw)
  – Dry Desert Climates (BW)
  – Humid Continental- mild summer (Dfb)


• BUT..You do have to be able to read a
  map and know the climate zones!!!
                   Latitude
• Determines solar energy rec’d
  – Angle

  – Tropics
     • Sun is high all the time
        – small Temp range
     • No seasons of summer and winter (just wet
       and dry)
  – Mid-latitudes
     • Angle changes
     • Time of exposure changes (day and night)
        – Large temp range (30+)
     • Seasons
• Polar
  – All light or all dark
  – Daily temp range small, yearly range large.

• Latitude determines the wind belt, brings
  weather.
  – Winds affect humidity, ppt, temp, cloud cover
  – Ocean currents
  – Mountain ranges
     • High and low pressures control rain too.
     • Belts shift seasonally
  Heat absorption and Release
• The way solar energy strikes earth and is
  absorbed or released influences temp.
  – Land vs. Water:
     • Land warms faster (unmoving)
     • Water warms slower (waves, currents keep mixing)
     • Water takes more energy to warm 1 degree
       (specific heat)
     • Water releases heat more slowly
  – Evaporation
     • More water evaporates over water than over land
     • Evaporation is a cooling process
          Factors affecting surface temperature
                          Latitude
                           Altitude
                       Ocean Currents
          Differential heating of land and water
                       Cloud cover
                       Local effects




January                       July
            No wind when land
            and ocean
            temperatures        Land and sea breezes:
            comparable
                                *Land surface heat
                                more in daytime, cools
                                more at night
       Surface                  ►
       heating                          Results in
       initiates                        diurnal reversal
       upward                           in wind
       expansio                         directions
       n over                   ►
       land                                 Pattern
                                            reverses at
                                            night after
                                            land
Cellular circulation                        becomes
develops and                                cooler than
strengthens during                          ocean
afternoon
              Ocean Currents
• Currents influence air that contacts it.
• Winds towards shore… away from shore...
  – N.Europe: big influence, U.S. not much.
www.ldeo.columbia.edu/.../
ocean_index.html
           Seasonal Winds
  – Heat difference btwn land and water
• Summer: land heats faster and pulls
  ocean air in
• Winter: land cools faster so ocean is
  warmer and air over ocean rises, pulling in
  land air
• “Monsoon” seasonal wind
  – Air moves from H to L pressure and brings
    torrential rains, etc…
Monsoon Definition:
-A monsoon is a seasonal shift in the prevailing wind direction, that usually brings with it a different kind of
weather.
-The persistent wind flow is driven by a warm air mass with low pressure at the surface that forms over the
continent as it is warmed by the sun. Air from the relatively higher pressure air mass over the ocean flows
toward the low pressure over land. -Widespread torrential rains, and even severe thunderstorms, accompany
the "onset" of the monsoon.
 -The Indian Ocean version of the hurricane, called a "cyclone", can also occur and move ashore in
association with the onset of the monsoon. These cyclones have at times killed thousands of people who live
in the low-lying areas along the eastern coast of India and Bangladesh.
- A weaker version of this monsoon occurs over the normally dry southwestern United States in the later


summer when more humid air, accompanied by thunderstorms, invades the region. www.weatherquestions.com
            TOPOGRAPHY
• Topography: shape of land
  – Elevation
  – Mountains change temp and moisture.
    • Rising, cooling (adiabatic), raining
    • Sinking, adiabatic warming, dry
       – Chinook: Rockies
  – Cold mountain winds: way cold, way high
    • Often blow N to S.
www.geog.ucsb.edu
       http://exploringa
       frica.matrix.msu
       .edu/curriculum/
       lm6/activitythre
       e1.htm

1) How would you
describe the
physical landscape
of Africa?

You will note that
most of the eastern
third of Africa (from
south to north) is
high altitude.

2) List the ways
that altitude may
impact the way land
is used by people.
                 Glaciers
• Glaciers: masses of moving ice that can
  cause erosion.
• Snowline: the elevation above which ice
  and snow remain thought the year.
• Snowfield: (or Ice field) motionless mass
  of permanent snow and ice.
  – Found near the poles, lower latitudes, tops of
    some mountains.
Jakobshavn glacier, Greenland




       stratus.ssec.wisc.edu/.../ Image1.html
http://www.usu.edu/planetearth/snowline.jpg
                   Snowfield




http://myweb.students.wwu.edu/~belangt/Snowfield.jpg
• Accumulation of water: avg temp in polar
  and high elevation is always near or below
  freezing…so the snow accumulates.
• Firn: snow crystals change into sm. grains
  of ice (due to melting & refreezing).
  – Steel-blue “snow”: firn is compressed (due to
    great pressures/layers)
• Snow and ice accumulate to a great
  thickness
• Ice starts to move downslope due to
  gravity.
  – Balance betwn Lg. snowfalls and ice melting,
    & cold temps.
www.uwsp.edu/.../ glaciation_causes.html
          Types of Glaciers
• Determined by SIZE & LOCATION.
• Valley
  – Formed in mountainous regions
  – Long, narrow wedge-shaped
    • Ex’s: Alaska, the Himalayas, the Andes, Alps
• Continental Ice Sheets
  – Covers large land areas (millions of sq.
    kilometers)
  – Found only in Greenland an Antarctica
                                            http://www.micktravels.com/antarctica/parad
                                            ise/35-zodiac-and-glacier.jpg
http://whirledview.typepad.com/whirledvie
w/images/glacier.jpg
     Movements of Glaciers
• Move about 100m/year to a few cm/yr to a
  km/year.
• BASAL SLIP: weight of ice eventually
  exerts enough pressure to melt the ice in
  contact w/ the ground.  lubricant.
  – Movement by melting and refreezing
• INTERNAL PLASTIC FLOW: Solid ice
  crystals slip over each other slow
  forward motion.
          Glacial Features
• Crevasses: large cracks
• Ice Sheets moving outward in continental
  ice sheets.
  – Ex: Ice Ross Shelf (size of Texas)
• Icebergs: broken of pieces of ice sheets
  that drift in the ocean.
  – 90% of an iceberg is below water!!!
Alps: Taken 4/06 on the way to Italy.
www.alaska.net/~house/
kaktovikbanerjeephotos.html

				
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