NEWTON: Land Isotherm Direction in Winter
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Name: Meenakshi
Status: student
Grade: 9-12
Location: IN
Country: USA
Date: Winter 2013-14

Why do isotherms on land bend towards equator in the month of January in the Northern hemisphere?

Isotherms are lines of equal temperature. As things cool off in the Northern Hemisphere winter, any given line, say 60 degrees Fahrenheit will, like many of the birds, head south to where the temperature is 60 degrees. It will not stay where it was because it gets colder than 60 degrees.

Having said that, remember that land cools off faster and more than the oceans. Isotherms over the oceans may move south in winter, but they move nowhere near the distance they do on land. It is this difference in movement that gives the isotherms their distinctive bend over the continents.

In summer he situation is reversed.

Hopes this helps. Bob Avakian


Isotherms on weather maps are lines through geographic areas that report the same temperature.

Looking at the map at this URL:

So, if as you suppose, that Isotherms predominantly bend to the equator, it may be because temperatures are warmer at the equator. But in general, isotherms are complete circles.

Sincere regards, Mike Stewart

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