Transcript Jet Stream
Atmosphere in Motion Lesson 1 Review How many levels of the Atmosphere? High Pressure is generally associated with what type of weather? Stable or Unstable? What is Relative Humidity? Dew point temperature is the point at which precipitation starts, True or False? Radiation The heat energy of the Sun reaches the Earth as radiation or solar energy. Radiation transfers heat by means of heat waves. Radiation that reaches the Earth is absorbed by land and water surfaces. Surface features influence the amount of radiation absorbed by the Earth. Conduction The passage of energy, particularly heat and electricity through an object. Heated molecules move more rapidly than cold molecules. Heat is transferred from fast moving molecules to slow moving molecules until all are moving at the same speed. A good example of conduction is a stove heating a pan. Convection The most efficient method of heating the atmosphere. Air is first heated by radiation and conduction. The air absorbs the heat energy. Warm air is forced upward as cold air flows in displacing the warm air. Convection currents cause constant cold air for warm air until heat is evenly distributed Convection Convection currents cause a constant exchange of cold air for warm air until heat is distributed evenly. Advection The horizontal transfer of a heat, caused by air movement. When the wind blows, it is simply movement by or within the local air mass. Advection is an important factor in the global circulation of air. Insolation The rate at which the Earth’s surface is heated by solar radiation. The amount received at any point on the Earth’s surface is dependent on the angle that the Sun’s rays make with the horizon Greater in the equatorial zone than anywhere else on the Earth’s surface due to the angle of incidence. Heat Balance If there was no balance of heat among the Earth, its atmosphere, and space, the Earth would become increasingly warmer. Of all the solar radiation arriving at the top of the atmosphere, 31 percent is reflected into space by clouds and atmospheric dust; 19 percent is absorbed directly into the atmosphere; and 46 percent reaches the Earth directly. Wind When air is heated, it rises. This occurs because the heat applied to it has decreased its density to the point where it is lighter in weight than the surrounding air. The surrounding cooler air pushes the lighter, heated air upward. Coriolis Effect The Earth rotates on its axis in such a way that an observer in space over the North Pole would see the Earth turning in a counterclockwise direction. The Pressure Gradient The high-pressure areas of the atmosphere are the mountains, and the low-pressure areas are the valleys. The wind flows from these high-pressure mountains into the low-pressure valleys. H H L Local and Surface Air Movement The general circulation of air is complicated by the irregular distribution of land and water areas. Different types of surfaces differ in the rate at which they absorb heat from the Sun and transfer heat to the atmosphere. Some surfaces give off or reflect a great amount of heat. Sand • Rocks • Plowed areas • Barren land • Other surfaces tend to retain heat. Meadows • Planted fields • Water • Local and Surface Air Movement Moving air flowing around obstructions tends to break into eddies. The Jet Stream The jet stream is a narrow current of air, which moves around the Earth in wavelike patterns. It is like a “river” of wind moving at a high rate of speed. The jet stream varies from about 100 to 400 miles wide and 1 to 3 miles thick. Winds usually have a speed of 150 to 300 mph, but speeds of 450 mph have been recorded. Its general motion is from west to east. Quick Answer Conduction is the passage of energy, particularly heat and ____________ electricity, through an object. An example is a frying pan Convection is the process whereby air absorbs heat energy. ____________ Warm air is forced upward as cold air flows displace the warm air. The horizontal transfer of a heat, caused by air movement is Advection called ________________. A good example is fog. Insolation ________________ is the rate at which the Earth’s surface is heated by solar radiation. A B A B Quick Answer Coriolis Effect This effect is called the _________________ The movement of the ball…is it real or apparent? Apparent Different land surfaces retain or reflect solar energy (heat) Sand differently. ___________ is a good example of terrain that reflects solar energy (heat). Water absorbs or reflects solar energy (heat). Absorbs Jet This is called a _________ Stream ___________. Summary Atmosphere in Motion • • • • • Conduction and Convection Advection Insolation Coriolis Effect Jet Stream