AIRS Daily Earth Maps from Space
AIRS Daily Earth Maps From Space
what_is_a_millibar
What is a millibar?
A millibar is a unit used to describe an amount of air pressure.
Air pressure is the force exerted on you by the weight of tiny particles of air (air molecules). Although air molecules are invisible, they still have weight and take up space. Since there's a lot of "empty" space between air molecules, air can be compressed to fit in a smaller volume. Earth's gravity causes the downward force that we know as "weight." Since the pressure depends upon the amount of air above the point where you're measuring the pressure, the pressure decreases as you go higher.
When it's compressed, air is said to be "under high pressure". Air at sea level is what we're used to, in fact, we're so used to it that we forget we're actually feeling air pressure all the time.
Air pressure can tell us about what kind of weather to expect as well. If a high pressure system is on its way, often you can expect cooler temperatures and clear skies. If a low pressure system is coming, then look for warmer weather, storms and rain.
Since the unit called "millibar" is in the metric system, 1000 millibars is equal one bar. A bar is a force of 100,000 Newtons acting on a square meter, which is too large of a unit to be a convenient measure of Earth's air pressure.
High atmospheric pressure usually means cooler temperatures and clear skies
Low atmospheric pressure usually means warmer temperatures , storms and rain
