Transcript Insolation And Local Factors - Geog

Insolation And Local
Factors
IB SL
5 Main Factors: Insolation
• Height of the sun.
• Height above sea level.
• Distance from land and sea.
• Prevailing Winds.
• Ocean Currents.
Height Of The Sun
• Lower latitudes (equatorial regions) have higher
temperatures than higher latitudes (Poles) this is
as a result of the amount of heating that each
area receives.
• Places near the equator receive direct heat on a
small surface area, and experience little energy
loss via absorption, scattering and reflection, as
there is a relatively small amount of atmosphere
to pass through.
• Towards the Poles, the surface area to be heated
increases, as does the amount of atmosphere to
pass through, increasing losses via, absorption,
scattering, and reflection.
Height Above Sea Level
• The atmosphere is heated from ground level
upwards via long-wave radiation.
• The higher up a mountain you go, the smaller
the surface area available to heat the
atmosphere above.
• This, in combination with a decrease in the
ability of the air to retain heat results in lower
temperatures.
Distance From Land And Sea
• Land and sea have vastly different specific heat
capacities (the amount of energy needed to raise
1kg of a substance by 1 degree).
• They have different abilities to absorb, transfer
and radiate heat energy.
• Generally, land surfaces respond to heating on a
daily basis (diurnal) meaning that differences
between day and night temperatures can be into
double figures, but sea surfaces respond over a
period of months and retain heat for longer.
• The sea heats up and cools down more slowly
than the land, acting to moderate temperatures
for coastal locations.
Prevailing Winds
• The temperature of a wind and the subsequent
effect it has on an area is dependent on:
1. Where it originated.
2. The surfaces it has blown over.
• Winds coming from the land in winter can be
exceptionally cold, whilst winds coming from the
sea in winter will be mild in comparison.
Ocean Currents
• Ocean currents can be either warm or cold
and they act to either raise or lower
temperatures of the coastal areas they flow
towards.
• The North Atlantic drift is the major current
acting on the UK and subsequently raises
temperatures above what they should be for
places along the same latitude.
Local Factors: 1
Amount of cloud cover:
• Little cloud in the day reduces the amount of
absorption, reflection and scattering that
occurs, allowing for more insolation to reach
the Earth.
• At night, the same situation allows more heat
to escape into the atmosphere - lowering
temperatures.
• At night, cloud acts to trap heat in the lower
atmosphere - moderating temperatures.
Local Factors: 2
Aspect:
• The way a slope (land) faces can have a large
impact on the amount of insolation received.
• This becomes important when planting crops
in valleys, as one slope will be cooler than the
other, leading to a shorter growing season.
Activity
• Using Section 6; P179 plus P183-186 from Essential
AS Geography, answer the following...
1. What are the defining differences between Weather
and Climate?
2. How do the following factors alter temperatures in
different areas: Albedo, Ocean Currents, Air Masses,
and Cloud Cover?
3. How can development in an area change
temperature? Why?