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Lecture 4. More about Temperature. Incoming vs. Outgoing Radiation. Controls of Temperature. Latitude Land and Water Ocean Currents Elevation. Average Temperature in January. Average Temperature in July. Contouring. EXAMPLE. Contouring. Contouring. Daytime Warming.

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Lecture 4 l.jpg

Lecture 4

More about Temperature



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Controls of Temperature

  • Latitude

  • Land and Water

  • Ocean Currents

  • Elevation




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Contouring

EXAMPLE




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Daytime Warming

On a clear, windless day, joggers may experience a temperature of 122oF near their feet, and a temperature of 90oF near their waist.





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Radiation Inversion Ingredients

  • Windless night

    • Wind mixes the air with turbulent eddies

  • A long night

  • Cloudless night

    • Clouds radiate infrared energy back to surface

  • A dry night

    • If dew forms, then latent heat of condensation is released.



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Daily Low Temperature

  • The lowest temperature may be reached after sunrise. Why?

    • After sunrise outgoing energy still exceeds incoming.

    • The solar angle is low at sunrise

    • If there is moisture, then evaporation cools the air.











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Measuring Temperature

  • Liquid in Glass Thermometers (mercury or alcohol)

  • Electric Thermometers (used in Automated Weather Stations)

    • Thermocouples

    • Platinum Resistance Thermometers

  • Radiometers (on satellites, weather balloons)

  • Bimetallic Thermometer (thermographs)


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Wind Chill

Why doe the wind make it feel colder?

  • On cold days our body warms a thin layer of air around us.

  • When the wind blows, this warm layer is replaced by cold air.

  • The faster the wind blows the colder we feel.


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The wind chill equivalent temperature tells us how cold it would have to be with no wind, in order for us to lose the same amount of heat.

  • This is new as of 2001!

    • - Replaces Paul Siple’s original work in Antarctica

    • - A bit “warmer” than the old formula

    • -Will be updated in the near future for sunshine


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Controls of Temperature would have to be with no wind, in order for us to lose the same amount of heat.

  • Latitude

  • Land and Water

  • Ocean Currents

  • Elevation


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Urban Heat Island would have to be with no wind, in order for us to lose the same amount of heat.

Stanley Park

Downtown Vancouver


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Urban Heat island would have to be with no wind, in order for us to lose the same amount of heat.

  • Decrease in:

    • Wind speed

    • Humidity (drainage systems take away water!)

  • Increase in:

    • Temperatures

    • Cloudiness

    • Precipitation

    • Fog

    • Pollution


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Causes of Urban Heat Island would have to be with no wind, in order for us to lose the same amount of heat.

  • Surfaces

    • Low albedos of asphalt and concrete

  • Heat trapping

    • Tall structures reflect and absorb outgoing radiation

  • Lack of water (rapid water run-off)

    • Less water  less evaporative cooling

  • Surface friction

    • Low wind speed  less mixing


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Causes of Urban Heat Island would have to be with no wind, in order for us to lose the same amount of heat.

  • Human produced heat

    • In buildings, automobiles

  • Particulates and Smog

    • Greenhouse enhancer, traps heat

  • Snow Removal

    • Decreases the albedo


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Heat Island Example would have to be with no wind, in order for us to lose the same amount of heat.

Areas that are “warm” appear in white/light gray.

Areas that are “cool” appear dark.

Atlanta


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Heat Island Example would have to be with no wind, in order for us to lose the same amount of heat.

Trees and vegetation appear in red.

Buildings, streets and urban land cover is white/blue-green/black.

Note the shape of the downtown region.

Atlanta


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Heat Island Example would have to be with no wind, in order for us to lose the same amount of heat.

Remember the shape of the downtown!


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Heat Trapping would have to be with no wind, in order for us to lose the same amount of heat.


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