|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||||
|
|
|
|
|
|
|
|
|
||
Water Transport of Heat
Water is about 1,000 times as dense as air, and, since the amount
of thermal energy transported by a moving fluid is proportional to its
density, a volume of water can transport about a thousand times as much
heat as an equivalent volume of air. The rate at which heat is
transported, called the heat flux, is measured in Joules of energy per unit
area per unit time, so the rate at which heat is transported is also
proportional to the speed of movement (wind speed in air or current speed
in the ocean). Since wind speed is typically on the order of 10 meters
per
second and ocean drift currents on the order of centimeters per second, the
air speed is about a thousand times larger than ocean speed. Therefore,
air moves a thousand times faster than water but carries only about 1/1000
as much heat per unit volume, which suggests that water is approximately of
equal importance to air in moving heat over the planet.
PREVIOUS: Conduction, Convection, and Radiation