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Anticyclogenesis
Anticyclogenesis is the development or strengthening of an anticyclonic circulation in the atmosphere. It is the opposite of anticyclolysis (the dissolution or weakening of an anticyclone) and has a cyclonic equivalent known as cyclogenesis. Anticyclones are alternatively referred to as high pressure systems. Process High-pressure systems 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. On weather maps, these areas show converging winds (isotachs), also known as confluence, or converging height lines near or above the level of non-divergence, which is near the 500 hPa pressure surface about midway up through the troposphere.Glossary of Meteorology (2009)Level of nondivergence.American Meteorological Society. Retrieved on 2009-02-17.Konstantin Matchev (2009)Middle-Latitude Cyclones - II. University of Florida. R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meteorological Phenomena
This glossary of meteorology is a list of terms and concepts relevant to meteorology and atmospheric science, their sub-disciplines, and related fields. A B C D E F G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclogenesis
Cyclogenesis is the development or strengthening of Cyclonic rotation, cyclonic circulation in the atmosphere (a low-pressure area). Cyclogenesis is an umbrella term for at least three different processes, all of which result in the development of some sort of cyclone, and at any size from the microscale meteorology, microscale to the synoptic scale meteorology, synoptic scale. * Tropical cyclones form due to latent heat driven by significant thunderstorm activity, developing a warm core. * Extratropical cyclones form as waves along weather fronts before occluding later in their life cycle as cold core cyclones. * Mesocyclones form as warm core cyclones over land, and can lead to tornado formation. Waterspouts can also form from mesocyclones, but more often develop from environments of high instability and low vertical wind shear. The process in which an extratropical cyclone undergoes a rapid drop in atmospheric pressure (24 millibars or more) in a 24-hour period is referred to a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anticyclonic Rotation
Anticyclonic rotation, or anticyclonic circulation, is atmospheric motion in the direction opposite to a cyclonic rotation. For cyclonic rotation, this motion is in a counter-clockwise direction in the Northern Hemisphere and clockwise in the Southern Hemisphere. Thus, just anticyclonic rotation would mean clockwise in the Northern Hemisphere and counter-clockwise in the Southern. For large-scale weather systems, greater than approximately , anticyclonic rotation only occurs for high-pressure systems. This is due to how the Coriolis effect acts on high-pressure systems. Large, low-pressure systems, such as tropical cyclones, have cyclonic rotation. Small scale rotating atmospheric features, such as tornadoes, water spouts, and dust devil A dust devil (also known regionally as a dirt devil) is a strong, well-formed, and relatively short-lived whirlwind. Its size ranges from small (18 in/half a metre wide and a few yards/metres tall) to large (more than 30 ft/10 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anticyclone
A high-pressure area, high, or anticyclone, is an area near the surface of a planet where the atmospheric pressure is greater than the pressure in the surrounding regions. Highs are middle-scale meteorological features that result from interplays between the relatively larger-scale dynamics of an entire planet's atmospheric circulation. The strongest high-pressure areas result from masses of cold air which spread out from polar regions into cool neighboring regions. These highs weaken once they extend out over warmer bodies of water. Weaker—but more frequently occurring—are high-pressure areas caused by atmospheric subsidence: Air becomes cool enough to precipitate out its water vapor, and large masses of cooler, drier air descend from above. Within high-pressure areas, winds flow from where the pressure is highest, at the center of the area, towards the periphery where the pressure is lower. However, the direction is not straight from the center outwards, but curved du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclonic Rotation
Cyclonic rotation or cyclonic circulation is the atmospheric motion in the same direction as a planet's rotation, as opposed to '' anticyclonic rotation''. In the case of Earth's rotation, the Coriolis effect causes cyclonic rotation to be in a counterclockwise direction in the Northern Hemisphere and clockwise in the Southern Hemisphere. A closed area of winds rotating cyclonically is known as a ''cyclone In meteorology, a cyclone () is a large air mass that rotates around a strong center of low atmospheric pressure, counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere as viewed from above (opposite to an ant ...''. References External linksCyclonic Rotation- AMS Glossary of Meteorology Climate patterns Rotation {{climate-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-pressure Area
A high-pressure area, high, or anticyclone, is an area near the surface of a planet where the atmospheric pressure is greater than the pressure in the surrounding regions. Highs are middle-scale meteorological features that result from interplays between the relatively larger-scale dynamics of an entire planet's atmospheric circulation. The strongest high-pressure areas result from masses of cold air which spread out from polar regions into cool neighboring regions. These highs weaken once they extend out over warmer bodies of water. Weaker—but more frequently occurring—are high-pressure areas caused by atmospheric subsidence: Air becomes cool enough to precipitate out its water vapor, and large masses of cooler, drier air descend from above. Within high-pressure areas, winds flow from where the pressure is highest, at the center of the area, towards the periphery where the pressure is lower. However, the direction is not straight from the center outwards, but curved du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Troposphere
The troposphere is the lowest layer of the atmosphere of Earth. It contains 80% of the total mass of the Atmosphere, planetary atmosphere and 99% of the total mass of water vapor and aerosols, and is where most weather phenomena occur. From the planetary surface of the Earth, the average height of the troposphere is in the tropics; in the middle latitudes; and in the high latitudes of the polar regions in winter; thus the average height of the troposphere is . The term ''troposphere'' derives from the Greek words ''tropos'' (rotating) and ''sphere, sphaira'' (sphere) indicating that rotational turbulence mixes the layers of air and so determines the structure and the phenomena of the troposphere. The rotational friction of the troposphere against the planetary surface affects the flow of the air, and so forms the planetary boundary layer (PBL) that varies in height from hundreds of meters up to . The measures of the PBL vary according to the latitude, the landform, and the t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmosphere
An atmosphere () is a layer of gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosphere is the outer region of a star, which includes the layers above the opaque photosphere; stars of low temperature might have outer atmospheres containing compound molecules. The atmosphere of Earth is composed of nitrogen (78%), oxygen (21%), argon (0.9%), carbon dioxide (0.04%) and trace gases. Most organisms use oxygen for respiration; lightning and bacteria perform nitrogen fixation which produces ammonia that is used to make nucleotides and amino acids; plants, algae, and cyanobacteria use carbon dioxide for photosynthesis. The layered composition of the atmosphere minimises the harmful effects of sunlight, ultraviolet radiation, solar wind, and cosmic rays and thus protects the organisms from genetic damage. The curr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weather
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 cloud cover, cloudy. On Earth, most weather phenomena occur in the lowest layer of the planet's atmosphere of Earth, atmosphere, the troposphere, just below the stratosphere. Weather refers to day-to-day temperature, precipitation, and other atmospheric conditions, whereas climate is the term for the averaging of atmospheric conditions over longer periods of time. When used without qualification, "weather" is generally understood to mean the weather of Earth. Weather is driven by atmospheric pressure, air pressure, temperature, and moisture differences between one place and another. These differences can occur due to the effect of Sun angle on climate, Sun's angle at any particular spot, which varies with latitude. The strong temperature contrast between polar and tropical air gives rise to the largest scale atmospheric circulations: the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synoptic Scale Meteorology
In meteorology, the synoptic scale (also called the large scale or cyclonic scale) is a horizontal length scale of the order of or more. This corresponds to a horizontal scale typical of mid-latitude depressions (e.g. extratropical cyclones). Most high- and low-pressure areas seen on weather maps (such as surface weather analyses) are synoptic-scale systems, driven by the location of Rossby waves in their respective hemisphere. Low-pressure areas and their related frontal zones occur on the leading edge of a trough within the Rossby wave pattern, while high-pressure areas form on the back edge of the trough. Most precipitation areas occur near frontal zones. The word '' synoptic'' is derived from the Ancient Greek word (), meaning "seen together". The Navier–Stokes equations applied to atmospheric motion can be simplified by scale analysis in the synoptic scale. It can be shown that the main terms in horizontal equations are Coriolis force and pressure gradient terms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Confluence
In geography, a confluence (also ''conflux'') occurs where two or more watercourses join to form a single channel (geography), channel. A confluence can occur in several configurations: at the point where a tributary joins a larger river (main stem); or where two streams meet to become the river source, source of a river of a new name (such as the confluence of the Monongahela River, Monongahela and Allegheny River, Allegheny rivers, forming the Ohio River); or where two separated channels of a river (forming a river island) rejoin downstream from their point of separation. Scientific study Confluences are studied in a variety of sciences. Hydrology studies the characteristic flow patterns of confluences and how they give rise to patterns of erosion, bars, and scour pools. The water flows and their consequences are often studied with mathematical models. Confluences are relevant to the distribution of living organisms (i.e., ecology) as well; "the general pattern [downstream o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
