Imagine an experiment with dozens of dependent variables and no
controlled variables. That’s a good way to think about a weather
forecast. The sun, the source of all energy on Earth, would be the
independent variable, well, sort of. Even though the sun rises and
sets on a steady schedule, and sends out fairly steady amounts of
energy, the Earth keeps turning below it! And because
our Earth is round, energy from the Sun heats the planet unevenly.
This means temperature and pressure change
with space and time. Clouds drift in and out of the scene, and
different concentrations of gases affect
the
weather “experiment”.
Forecasting weather is one of the hardest and most complicated things scientists
do on a daily basis. These scientists, called meteorologists, use many tools
to tackle the job of weather forecasting. They start by looking
at images provided by weather satellites. Here's a satellite image
of the
United
States.
Can you
tell where it's cloudy?
Along with showing us where the clouds are (the white
and grey areas) this satellite image suggests that precipitation
is occurring in the Pacific Northwest
and much of the Midwest. You could forecast rain for central
California from this satellite image alone.
And you'd probably be right. A single satellite image
holds
tons of
information.
A meteorologist looking at this image could tell where the mild
air is, where the cold fronts and warm fronts
are, and even identify stormy weather. Click on this image
to see the cold fronts, warm fronts, and areas of High and
Low pressure. You can click back and forth
between the images to see the pattern, try it!
Continue...