Transcript Types of Rainfall

Types of Rainfall & Ocean
Currents
World Climate Patterns
World Geo 3200/3202
Unit 2, Chpt 4
November 2010
Outcomes
• In this lesson you will:
• 2.3.6 Define the terms windward, leeward, and
rain shadow. (k)
• 2.3.7 Examine how the type of rainfall (i.e.,
orographic, frontal, and convectional) is related
to the nature of location. (a)
• 2.3.8 Explain how wind systems and
precipitation are related. (k)
Types of Rain
•
Three types of rainfall:
1. Relief Rain
2. Convectional
3. Frontal / Cyclonic Rain
Relief Rainfall
• Stage 1.
Warm wet air is forced to rise
over high land.
• Stage 2.
As the air rises it cools &
condenses. Clouds form &
precipitation occurs.
• Stage 3.
The drier air descends &
warms.
• Stage 4.
Any moisture in the air (e.g.
cloud) evaporates
Convectional Rainfall
• Stage 1
The sun heats the ground &
warm air rises.
• Stage 2
As the air rises it cools &
water vapour condenses to
form clouds.
Convectional Rainfall
• Stage 3. When the
condensation point is
reached large cumulonimbus
clouds are formed.
• Stage 4.
Heavy rain storms occur
with thunder & lightening
due to the electrical charge
created by unstable
conditions.
Frontal / Cyclonic Rainfall
• Stage 1 An area of warm air
meets an area of cold air.
• Stage 2. The warm air is forced
over the cold air
• Stage 3. Where the air meets the
warm air is cooled & water
vapour condenses.
• Stage 4.
Clouds form & precipitation
occurs
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Part 2: Ocean Currents Outcomes
• In this lesson you will learn to...
• 2.4.1 Define the term ocean current. (k)
• 2.4.2 Analyze how ocean currents can create
different climatic conditions for two coastal
locations on the same latitude. (a)
Ocean Currents
• 1. Permanent or semi-permanent horizontal
movement of surface water (the top 100m)
• It is unusually cold or hot, when compared with
the surrounding water
• 2. Caused by and shaped by,
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prevailing winds,
variations in temperature
density of water
Coriolis force
Warm and Cold Currents
• Cold ocean currents: move water towards
the equator.
▫ For example the Humbolt or Peru Current carries cold
water from Antarctica toward the equator (along the
South American coast). Can you find it on page 60?
▫ Another example is the Labrador Current which
carries cold water from the Arctic Ocean down along
the Labrador coast towards the Grand Banks. Can you
find it on page 60?
Cold Ocean Currents…Practical Examples
• Mary’s Harbour on the
coast of Labrador is
affected by the Labrador
Current which gives
Mary's Harbour cool
summer temperatures &
surprising little
precipitation for a location
right on the oceans edge.
• Drying & cooling effect to
maritime climate
Newfoundland Coast
• LC brings both cool water & air south from the
Arctic
• When this meets the warm Gulf Stream, flowing
north from the equator, fog forms along our
coast
• There is a frontal effect created off our coast
contributing both to our precipitation & wet /
foggy weather conditions
Practical Examples
• Newfoundland's south
coast has ice-free ports
year-long while its north
coast has heavy ice for
several months.
• The difference in latitude
is not enough to explain
this difference in ice.
• Can you explain it with
ocean currents?
Warm and Cold Currents
• Warm ocean currents: Move water away from
warm equatorial regions.
▫ For example the Gulf Stream moves warm water from the
Gulf of Mexico northeast toward England. Can you find it
on page 60?
▫ Another good example is the Japanese current which moves
warm water from Japan northeast towards Vancouver. Can
you find it on page 60?
Ocean Currents & the Affect on
Climate
• Affect of cold ocean currents
▫ Cools the summer temperature;
▫ Reduces precipitation; cooler air holds less
moisture.
▫ Maritime Climate
Ocean Currents & the Affect on
Climate
• Affect of warm ocean currents
▫ Warms the winter temperature;
▫ Increases precipitation; warmer air holds more
moisture.
▫ El Nino
• http://www.cdli.ca/courses/geog3202/unit02_
org03_ilo02/b_activity.html