|
You experience weather at the Earth's surface, but there is weather high
in the atmosphere, too. Have you ever taken a ride in a hot-air balloon
or climbed a high mountain? You would know that the air temperature usually
decreases with altitude. The basic reason has to do with where the atmosphere
receives its heat and where it loses its heat. The Earth's surface is
heated by the sun at some times and places. It loses heat to outer space
at other times and places. On balance, however, the Earth's surface gains
more heat than it loses. The atmosphere near the ground is then heated
by the ground. High up in the atmosphere, however, the air loses more
heat to space than it absorbs from sunlight. Air pressure decreases with
increasing altitude.
Many kinds of devices have been invented for measuring things like temperature,
pressure, and humidity in the upper atmosphere. These devices, called
sondes, are packages of several instruments. Balloons are used to carry
them up through the atmosphere. As they rise, they send back measurements
by radio. Eventually the balloon pops, and the instruments crash back
to Earth. Their fall is not dangerous to humans, because the instruments
are very small and light.
Back To Top
|
