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Weather and Climate
• Weather – atmospheric conditions over a short period of time (day), studied by meteorologists.
• Climate – atmospheric conditions over a long period of time (months and years), studied by climatologists.
• Of main interest is precipitation and temperature.
Identify the factors that affect climate
and explain how each
affects climate.
Low Latitudes: Between the tropic of Cancer and Tropic of Capricorn, warm hot climates
North or South of the Equator makes a difference on the temperature and the wind patterns
High Latitudes: Warm when the poles are tilted towards the sun and Cool when the poles are tilted away from the sun
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THE EARTH’S AXIS - Seasons
The earth’s axis is tilted from the vertical by 23 ½ degrees.
The earth's orbit and tilt
A common misconception is that the seasons are caused by how far the earth is from the sun.
In Canada, we are actually closer to the sun in the winter time by about 900 000 kilometers.
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As we move from December to June the number of daylight hours increases due to the tilt of the axis (earth surface receives more direct sunlight). June to December daylight hours get shorter earth cools.
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Summer – Energy more intense
Winter – Energy less intense
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How does latitude affect climate?
As latitude ________, the averageannual temperature _________.
0° Latitude 90°
Tem
per
atu
redecreases
increases
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How does closeness to a large body of water affect climate?
Water __________ the temperature._______ summers. _______ winters.
City B is closer to a large body of water.
Its temperature line is flatter (moderated).
moderates
Cities A & B are located at the same latitude.
Cooler Warmer
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Washington DC - Man made body of water. Why?
The windward sides of the Adirondacks & Catskills receive a great deal more
precipitation
The leeward sides of the
Adirondacks & Catskills
receive much less
precipitation
How does the Orographic Effect
affect climate?
Windward Side: ___________Leeward Side: _____________
cool, moistwarm, dry
Temperature drop of 1ºC for each 100 m of elevation.
We live in the troposphere. Temperature decreases
with elevation.
During summer, temperature is strongly controlled by elevation -- cold at the higher reaches of the Alaska and Brooks Ranges, and warmer in the lowlands.
How does elevation affect climate?
As elevation _________, the averageannual temperature __________.
Elevation
Tem
per
atu
reincreases
decreases
• Water covers 70% of the earth’s surface.
• Water has a high heat capacity.• Water serves as a reservoir of
heat.• Ocean currents distribute the
absorbed heat around the world.
• The primary forces for surface ocean currents are:
• 1. Solar Heating
• 2. Winds
• 3. Gravity
• 4. Coriolis Effect
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• Ocean currents enable the flow of energy from the tropics to polar regions and back.
• Large ocean currents are constrained by the continental masses found bordering the three oceanic basins. Continental borders cause these currents to develop an almost closed
circular pattern called a gyre.
How do ocean currentsaffect climate?
Warm Currents: warmer climateCold Currents: cooler climate
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Wind CurrentsWINDS
Winds are due to the relationship between air temperature and air density.
Changes in air pressure cause movement of air.
Movement of air is called WIND.
Global Winds
The jet stream are high speed winds which travel all around the earth. They form at the boundary between cold air and warm air masses.
Cool air masses move towards the equator.
Warm air masses move towards the poles
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Upward movement - air lifts off the surface as the air is heated. This creates an area of low pressure.
Downward movement -there is a piling up effect. This creates an area of high pressure.
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A cold front occurs when a more dense air mass pushes
under a less dense air mass.
cumulusnimbus(rain)
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cumulonimbus cumulus
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A warm front occurs when a less dense air mass rides up
over a more dense air mass.
Stratus (layer)
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Cirrus Stratus
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