9781422272510

two. The water that develops in the atmosphere then returns to the earth as rain, sleet, or snow. Precipitation is a part of the earth’s water cycle. Atmospheric pressure: Did you know that air has weight? This weight presses into everything air touches, creating pressure. This pressure is known as atmospheric pressure (also called air pressure ). Atmospheric pressure is the force exerted on the earth’s atmosphere by air. It is measured via the use of a barometer, which is a glass tube containing mercury that rises or falls based on atmospheric weight changes. If you’ve ever watched a weather forecast on television, you’ve probably heard the terms high-pressure and low pressure systems. A high-pressure system contains more pressure at the center of its system. These weather patterns rotate clockwise in the Northern Hemisphere, causing wind to blow away from the pressure (usually to the east or southeast). High-pressure systems are generally the result of cooler air and tend to produce clearer weather. A low-pressure system happens when there is lower pressure at the center of the system, causing the wind to blow counterclockwise, away from the pressure. This kind of system sucks in air from the higher pressure areas around it, leading to wind and unstable weather, like storms. Wind: While the obvious definition of wind is the way that air moves, there’s a lot more to it than that. Wind is caused because Earth’s surface is heated unevenly by the sun. This generates differences between temperature and atmospheric pressure, causing wind to develop in high-pressure systems and blow into low pressure systems. In simple terms, warm air rises and is replaced by cool air. This air movement is the primary force behind the winds that blow. Cloud cover: Clouds are formed as water evaporates and condenses within the atmosphere. There are different types of clouds, and each has its own shape and purpose. The three basic cloud shapes are cumulus, cirrus, and stratus.

11

Is Climate DifferentThan Weather?

Made with FlippingBook - Online magazine maker