Search results
Results From The WOW.Com Content Network
Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloudy. [1] On Earth, most weather phenomena occur in the lowest layer of the planet's atmosphere, the troposphere, [2] [3] just below the stratosphere.
The Earth's weather is a consequence of its illumination by the Sun and the laws of thermodynamics. The atmospheric circulation can be viewed as a heat engine driven by the Sun's energy and whose energy sink , ultimately, is the blackness of space.
Low-pressure systems form under areas of wind divergence that occur in the upper levels of the atmosphere (aloft). The formation process of a low-pressure area is known as cyclogenesis . In meteorology , atmospheric divergence aloft occurs in two kinds of places:
A surface weather analysis for the United States on 21 October 2006. High pressure areas are labeled "H". High-pressure areas form due to downward motion through the troposphere, the atmospheric layer where weather occurs. Preferred areas within a synoptic flow pattern in higher levels of the troposphere are beneath the western side of troughs.
As the clouds disperse, sunny weather replaces cloudiness in a cycle that can occur more than once a day. In winter, an inversion can lead to the development of ice pellets and freezing rain. Both these phenomena occur when snow melts in a warm layer aloft and falls into a colder layer near the surface.
Near the Earth's surface, friction causes the wind to be slower than it would be otherwise. Surface friction also causes winds to blow more inward into low-pressure areas. [2] [3] Winds defined by an equilibrium of physical forces are used in the decomposition and analysis of wind profiles.
The five components of the climate system all interact. They are the atmosphere, the hydrosphere, the cryosphere, the lithosphere and the biosphere. [1]: 1451 Earth's climate system is a complex system with five interacting components: the atmosphere (air), the hydrosphere (water), the cryosphere (ice and permafrost), the lithosphere (earth's upper rocky layer) and the biosphere (living things).
Temperature differences can cause air currents because warmer air is less dense than cooler air, causing the warmer air to appear "lighter." Thus, if the warm air is under the cool air, air currents will form as they exchange places. Air currents are caused because of the uneven heating of Earth's surface. [5] [6]