The motion of the air is not directly north and south but is affected by the momentum the air has as it moves away from the equator. The reason has to do with momentum and how fast a location on or above the Earth moves relative to the Earth's axis. Your speed relative to the Earth's axis depends on your location. In the graphic above right the person at the position on the equator arrives at the yellow line sooner than the other two.
Someone standing on a pole is not moving at all except that he or she would be slowly spinning. The speed of the rotation is great enough to cause you to weigh one pound less at the equator than you would at the north or south pole.
The momentum the air has as it travels around the earth is conserved, which means as the air that's over the equator starts moving toward one of the poles, it keeps its eastward motion constant.
The Earth below the air, however, moves slower as that air travels toward the poles. The result is that the air moves faster and faster in an easterly direction relative to the Earth's surface below the farther it moves from the equator. As the difference in temperature increases between the two locations the strength of the wind increases. Speeds this high usually happen in polar jet streams in the winter time. Airplanes can fly in the jet stream. Airplanes also fly in the mid to upper troposphere.
So, if an airplane flies in a powerful jet stream and they are traveling in the same direction, the airplane can get a boost. A visualization of the Northern Hemisphere's polar jet stream swirling weather patterns from west to east across North America.
The fast-moving air currents in a jet stream can transport weather systems across the United States, affecting temperature and precipitation. This will slow things up, making areas of low pressure move less predictably. The jet stream can also change the strength of an area of low pressure. It acts a bit like a vacuum cleaner, sucking air out of the top and causing it to become more intense, lowering the pressure system. The lower the pressure within a system, generally the stronger the wind, and more stormy the result.
On the other hand, a slower, more buckled jet stream can cause areas of higher pressure to take charge, which typically brings less stormy weather, light winds and dry skies. Earth is split into two hemispheres, and air is constantly moving around to spread heat and energy from the equator to the poles. Three large groups, or cells , in each hemisphere help to circulate this air within the lowest part of the atmosphere, the troposphere.
It impacts the way people dress each day and the types of structures built. Explore weather and its impacts with this curated collection of classroom resources. An atmosphere is the layers of gases surrounding a planet or other celestial body.
These gases are found in layers troposphere, stratosphere, mesosphere, thermosphere, and exosphere defined by unique features such as temperature and pressure. The atmosphere protects life on earth by shielding it from incoming ultraviolet UV radiation, keeping the planet warm through insulation, and preventing extremes between day and night temperatures. The sun heats layers of the atmosphere causing it to convect driving air movement and weather patterns around the world. Teach your students about the Earth's atmosphere with the resources in this collection.
We live at the bottom of an invisible ocean called the atmosphere, a layer of gases surrounding our planet. Nitrogen and oxygen account for 99 percent of the gases in dry air, with argon, carbon dioxide, helium, neon, and other gases making up minute portions.
Encyclopedic entry. Air is the invisible mixture of gases that surrounds the Earth. Air contains important substances, such as oxygen and nitrogen, that most species need to survive. A current is the steady, predictable movement of a fluid within a larger body of that fluid. Fluids are materials capable of flowing and easily changing shape. Join our community of educators and receive the latest information on National Geographic's resources for you and your students.
Skip to content. Twitter Facebook Pinterest Google Classroom. Encyclopedic Entry Vocabulary. A jet stream is a very cold, fast-moving wind found high in the atmosphere. Photograph by Barry Bishop, National Geographic. Media Credits The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit.
Last Updated Jan.
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