1. Wind speed and direction respond to pressure gradient forces that exist between high and low pressure areas. In the Northern Hemisphere and because of the rotation of the earth, winds circulate in a clockwise fashion around areas of high pressure and in a counter-clockwise manner around regions of lower pressure. Air pressure decreases relatively slowly with height in regions dominated by warm air and relatively rapidly with height in areas where cold air prevails. As a result, wind patterns in the upper atmosphere tend to flow in an oscillating manner around major pockets of warm and cold air.
<span>Horizontal pressure gradient force- results from the high and low pressure systems (highs, lows, troughs and ridges) in the atmosphere. Air tends to move air from regions of high pressure to regions of low pressure.
</span>Friction- the drag on the air by the earth's surface (e.g., plants, trees, buildings, mountains, etc.).
Friction always acts opposite to air motion
<span>Coriolis Force<span>Coriolis force- the force that results from Earth's rotation.The Coriolis force solely results from living on a rotating object -- Earth. It acts only on objects moving with respect to the earth's surfaceCentrifugal force- the tendency for a body to resist a change in direction.
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</span></span></span>2. The amount of sunlight striking an air mass influences its temperature. As the air heats up, it rises in the air column and begins sucking cool air in behind it. This causes the winds that drive much of the planet’s weather systems.
The weather is also affected by the local geography. For example, mountains often block winds and rainfall. This causes one side of the mountain to have very high amounts of rainfall and lush vegetation, while the far side of the mountains remain very dry and desolate.
The air pressure in an area can impede or encourage the flow of weather systems. In general, air masses flow from areas of high pressure towards areas of low pressure. Usually, storms occur in areas of extremely low pressure.
The amount of water in the atmosphere affects the local humidity and rainfall. Air masses that move across bodies of water often draw water up into the air before depositing it somewhere else as rain, snow or sleet
