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Topic 8 Water & Climate
• Water covers 70% of Earth surface.
• Water has been recycled for 3 billion
years!
• Fueled by solar energy, which causes liquid or
solid water to change into a gas, and by gravity
pulling water down in the atmosphere,
hydrosphere, and lithosphere.
FACTORS AFFECTING INFILTRATION
(a.k.a. Seep)
• Infiltration is the process by which water
on the ground surface enters the soil
• Slope of the land
– The steeper the slope the less infiltration
• Degree of saturation
– The more saturated the ground the less
infiltration
• Zone of saturation: open spaces filled with
water only.
• Zone of aeration: open spaces filled with
air and water.
•The water table
is the interface
between the
zone of
saturation and
the zone of
aeration.
• Porosity: % of open space compared to its
total volume
– The higher the porosity the more the
infiltration.
• Factors that affect porosity: shape, packing, and
sorting
• Permeability: the ability of material to allow
fluids to pass through
– A material can be porous and yet be
impermeable (not permeable)
• It depends how well the pores (spaces) are
connected
• Capillarity: water moves up (against
gravity) due to the attractive force between
water molecules and surrounding
particles.
– The smaller the pore space the greater the
capillarity.
• Vegetation intercepts precipitation slowing
it down which increases infiltration.
• Land use: pavement, farming, cutting
down trees (deforestation) decreases
infiltration.
FACTORS AFFECTING RUNOFF &
STREAM DISCHARGE
• Stream discharge: is the volume of water
that passes a given point in a stream.
• Runoff occurs when:
– It’s precipitation more than the water can
infiltrate.
• The pore space is already saturated.
• The slope of the land is too steep to allow
infiltration.
• There is water on the surface of the
ground. (ex. Puddles)
• Runoff often carries water rivers, which
carry water to the ocean (completing the
cycle).
• The greater the runoff the greater the
stream discharge. This is a direct
relationship.
FLOODING
• When a stream overflows.
• Precipitation exceeds infiltration.
• Hurricane’s storm surge.
• http://www.weather.com/video/hurricanesstorm-surge-29941
• http://abcnews.go.com/US/hurricanes/vide
o/hurricane-irene-storm-surge-movesbeach-building-14397948
• http://www.youtube.com/watch?v=cMFKB
g3BAPQ
• Rising of sea level.
• Sinking of the land.
• Tides.
Flood Safety
• http://www.youtube.com/watch?v=7YiB2yHyuo
Climate Notes
• Climate is the overall view of a region’s
weather conditions over a long time (100’s
of years).
• 2 major aspects of climate:
– Temperature
• (1) The average temperature over a year.
• (2) Range of average monthly temperatures.
– Moisture
• (1) Arid Climate: The annual average precipitation (P) is
less than the annual evapotranspiration (Ep).
• (2) Humid Climate: The annual average precipitation (P)
is more than the annual average evapotranspiration
(Ep).
1. Latitude and Temperature
• a. Low latitudes like
the Tropics have
high angles of
insolation and equal
duration of
insolation (~12
hours each day)
therefore there are
higher temps and
little temperature
variation throughout
the year.
• b. High
latitudes like
the Poles have
low angles of
insolation and a
variable
duration of
insolation (0-24
hrs each day)
therefore there
are lower
temps and a
wide range
temperature
variation
throughout the
year.
2. Latitude and Moisture
• a. Moisture varies with latitude because of
the location of planetary wind and pressure
belts.
• i. Low pressure (0°, 60°N & S) = lots of
precipitation due to air rising, expanding,
cooling and condensing. Ex/ tropical
rainforest
• i. High pressure (30°N & S, 90°N & S) =
little precipitation due to air sinking,
compressing, warming and evaporating.
Ex/ desert
Great Victoria Desert
29°S 129°E
Antarctic Desert
South Pole = 90°S
3. Large bodies of water
• a. The climate is moderated by the water’s
high specific heat. (Slow heating and
cooling.)
– i. Results in a marine climate. Winters are
warmer because the water is still warm from
summer and summers are cooler because the
water is still cold from winter.
Central Canada
England
23-32°F
41-50°F
• b. Inland areas (areas far from oceans or
large lakes) have a continental climate.
– i. Warm summers and cold winters. Without a
large body of water present – the air temperature
isn’t moderated.
Central Canada
England
23-32°F
41-50°F
4. Prevailing winds:
a. In the
US, the
winds are
from the
Southwest.
• b. The winds are caused by pressure
differences, unequal heating of Earth’s
surface, and the Coriolis effect.
5. Surface ocean currents
• a. Currents flowing away from the equator
carry warm water to high latitudes, while
currents from high latitudes carry cool
water to the equator.
• b. A cool ocean current will cause cooler
temps, and less precipitation. (Cold air is
more dense so it will not rise.)
• c. A warm ocean current will cause
warmer temps, and more precipitation.
(The warm water will warm up the air –
warm air rises creating low pressure =
rain.)
6. Elevation
• a. High altitudes at ANY latitude have cool
climates.
– i. The air rises, expands and cools.
– ii. Lower amount of greenhouse gases at high
altitudes (less air).
Huascaran – Peru’s
tallest mountain.
9°S 77.6°W
7. Mountains
8. Vegetation
• a. Arid climate have desert vegetation.
• b. Hot, humid climates have tropical
rainforest vegetation.
• c. Deforestation changes climate – it
becomes hotter and less humid due to
more run-off and less infiltration.
• d. Urbanization: building cities.
9. Cloud cover
• a. More clouds = cooler temps. (The
clouds block the sunlight so that it can’t be
absorbed by Earth’s surface and changed
into heat.)
• b. The equator has lots of thunderstorm
clouds (low pressure) so it’s not as hot as
at 30°N & S (high pressure) where there
isn’t any clouds to block the sunlight.
Climate Change
• Natural cooling and warming cycles.
• Ice Age – during a cooling cycle glaciers
advance (grow) from polar regions down
towards mid-latitudes.
• Global warming – unnatural warming cycle.
• Greenhouse effect
El Nino
• http://esminfo.prenhall.com/science/geoani
mations/animations/26_NinoNina.html