Earth's Surface Does Not Heat Evenly

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Imagine walking across two surfaces on a hot summer day.  One surface is an asphalt parking lot.  The other surface is a grassy park.  Which would you prefer?

This everyday experience demonstrates an important concept when considering how heat is moved through Earth's atmosphere:  that different surfaces heat up at different rates.  

THE SPEED, AND DEGREE TO WHICH A SURFACE WILL HEAT UP IS DETERMINED BY HOW MUCH INSOLATION IT ABSORBS.  

The amount of insolation a surface absorbs is determined by three important characteristics:

Color

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DARK SURFACES ABSORB MORE INSOLATION THAN LIGHT SURFACES.

As a result dark surfaces heat up faster.  This should be another familiar sensation to anyone who has made the bad decision to wear a black tee shirt on a hot summer day.

LIGHT COLORED SURFACES REFLECT MORE INSOLATION THAN DARKER SURFACES.  As a result they heat up much more slowly.  

Texture

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The texture of an object effects it's surface area.  Rough surfaces with lots of bumps and folds have much more surface area than smooth objects.  

ROUGH SURFACES HAVE MORE SURFACE AREA TO ABSORB INSOLATION ON, CAUSING THEM TO HEAT UP FASTER.

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Vegetation

Plants help to cool down surfaces because they do photosynthesis.  The process of photosynthesis requires sunlight, which means plants use insolation before it can become heat.

SURFACES COVERED BY VEGETATION HEAT UP SLOWLY

BARREN SURFACES HEAT UP QUICKLY

 

SPECIFIC HEAT

Earth is covered by surfaces with a wide variety of characteristics.  One important difference that exists between materials is their specific heat.

SPECIFIC HEAT IS THE AMOUNT OF ENERGY NEEDED TO RAISE THE TEMPERATURE OF A SUBSTANCE.

THE COVER OF THE ESRT LISTS THE SPECIFIC HEAT OF VARIOUS MATERIALS.

NOTICE THAT WATER HAS A VERY HIGH SPECIFIC HEAT.  This means water changes temperature VERY SLOWLY

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In contrast, land heats up and cools down very quickly.

BECAUSE OF THIS DIFFERENCE, COASTAL AREAS HAVE MUCH MORE STABLE CLIMATES

  • WARMER WINTERS
  • COOLER SUMMERS