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Cumulus Congestus Cloud
Cumulus congestus clouds, also known as towering cumulus, are a form of cumulus that can be based in the low or middle height ranges. They achieve considerable vertical development in areas of deep, moist convection. They are an intermediate stage between cumulus mediocris and cumulonimbus, sometimes producing showers of snow, rain, or ice pellets. Precipitation that evaporates before reaching the surface is virga. Description Cumulus congestus clouds are characteristic of unstable areas of the atmosphere which are undergoing convection. They are often characterized by sharp outlines and great vertical development. Because they are produced by (and primarily composed of) strong updrafts, they are typically taller than they are wide, and cloud tops can reach , or higher in the tropics. Cumulus congestus clouds are formed by the development of cumulus mediocris generally, though they can also be formed from altocumulus castellanus or stratocumulus castellanus, which are forms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cumulus Cloud
Cumulus clouds are clouds which have flat bases and are often described as "puffy", "cotton-like" or "fluffy" in appearance. Their name derives from the Latin ''cumulo-'', meaning ''heap'' or ''pile''. Cumulus clouds are low-level clouds, generally less than in altitude unless they are the more vertical cumulus congestus form. Cumulus clouds may appear by themselves, in lines, or in clusters. Cumulus clouds are often precursors of other types of clouds, such as cumulonimbus, when influenced by weather factors such as instability, moisture, and temperature gradient. Normally, cumulus clouds produce little or no precipitation, but they can grow into the precipitation-bearing congests or cumulonimbus clouds. Cumulus clouds can be formed from water vapour, supercooled water droplets, or ice crystals, depending upon the ambient temperature. They come in many distinct subforms and generally cool the earth by reflecting the incoming solar radiation. Cumulus clouds are part of the la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Civil Aviation Organization
The International Civil Aviation Organization (ICAO, ) is a specialized agency of the United Nations that coordinates the principles and techniques of international air navigation, and fosters the planning and development of international air transport to ensure safe and orderly growth. ICAO headquarters are located in the '' Quartier International'' of Montreal, Quebec, Canada. The ICAO Council adopts standards and recommended practices concerning air navigation, its infrastructure, flight inspection, prevention of unlawful interference, and facilitation of border-crossing procedures for international civil aviation. ICAO defines the protocols for air accident investigation that are followed by transport safety authorities in countries signatory to the Chicago Convention on International Civil Aviation. The Air Navigation Commission (ANC) is the technical body within ICAO. The commission is composed of 19 commissioners, nominated by the ICAO's contracting states and ap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Eruption
Several types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs and volcanic blocks), and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behavior has been observed. Some volcanoes may exhibit only one characteristic type of eruption during a period of activity, while others may display an entire sequence of types all in one eruptive series. There are three different types of eruptions: * Magmatic eruptions are the most well-observed type of eruption. They involve the decompression of gas within magma that propels it forward. * Phreatic eruptions are driven by the superheating of steam due to the close proximity of magma. This type exhibits no magmatic release, instead causing the granulation of existing rock. * Phreatomagmatic eruptions are driven by the direct interaction of magma and water, as opposed to phreatic eru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flammagenitus Cloud
A flammagenitus cloud, also known as a flammagenitus, pyrocumulus cloud, or fire cloud, is a dense cumuliform cloud associated with fire or volcanic eruptions. A flammagenitus is similar dynamically in some ways to a firestorm, and the two phenomena may occur in conjunction with each other. However, either may occur without the other. Formation A flammagenitus cloud is produced by the intense heating of the air from the surface. The intense heat induces convection, which causes the air mass to rise to a point of stability, usually in the presence of moisture. Phenomena such as volcanic eruptions and forest fires can induce formation of this cloud, by mechanisms similar to those that form homogenitus clouds. The presence of a low-level jet stream can enhance its formation. Condensation of ambient moisture (moisture already present in the atmosphere), as well as moisture evaporated from burnt vegetation or volcanic outgassing (water vapour being a dominant component of volcani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precipitation (meteorology)
In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor (reaching 100% relative humidity), so that the water condenses and "precipitates" or falls. Thus, fog and mist are not precipitation but colloids, because the water vapor does not condense sufficiently to precipitate. Two processes, possibly acting together, can lead to air becoming saturated: cooling the air or adding water vapor to the air. Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within a cloud. Short, intense periods of rain in scattered locations are called showers. Moisture that is lifted or otherwise forced to rise over a layer of sub-freezing air at the surface may be con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Instability
Atmospheric instability is a condition where the Earth's atmosphere is generally considered to be unstable and as a result the weather is subjected to a high degree of variability through distance and time. Atmospheric stability is a measure of the atmosphere's tendency to discourage or deter vertical motion, and vertical motion is directly correlated to different types of weather systems and their severity. In unstable conditions, a lifted thing, such as a parcel of air will be warmer than the surrounding air at altitude. Because it is warmer, it is less dense and is prone to further ascent. In meteorology, instability can be described by various indices such as the Bulk Richardson Number, lifted index, K-index, convective available potential energy (CAPE), the Showalter, and the Vertical totals. These indices, as well as atmospheric instability itself, involve temperature changes through the troposphere with height, or lapse rate. Effects of atmospheric instability in mois ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thunderstorm
A thunderstorm, also known as an electrical storm or a lightning storm, is a storm characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere, known as thunder. Relatively weak thunderstorms are sometimes called thundershowers. Thunderstorms occur in a type of cloud known as a cumulonimbus. They are usually accompanied by strong winds and often produce heavy rain and sometimes snow, sleet, or hail, but some thunderstorms produce little precipitation or no precipitation at all. Thunderstorms may line up in a series or become a rainband, known as a squall line. Strong or severe thunderstorms include some of the most dangerous weather phenomena, including large hail, strong winds, and tornadoes. Some of the most persistent severe thunderstorms, known as supercells, rotate as do cyclones. While most thunderstorms move with the mean wind flow through the layer of the troposphere that they occupy, vertical wind shear sometimes caus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nimbostratus Cloud
A nimbostratus cloud is a multi-level, amorphous, nearly uniform and often dark grey cloud that usually produces continuous rain, snow or sleet but no lightning or thunder. in the Oxford Dictionaries Online Although it is usually a low-based cloud, it actually forms most commonly in the middle level of the troposphere and then spreads vertically into the low and high levels. Nimbostratus usually produces precipitation over a wide area. ''Nimbo-'' is from the Latin word ''nimbus'', which denotes cloud or halo. Downward-growing nimbostratus can have the same vertical extent as most large upward-growing cumulus, but its horizontal extent tends to be even greater. Appearance Nimbostratus has a diffuse[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rainband
A rainband is a cloud and precipitation structure associated with an area of rainfall which is significantly elongated. Rainbands can be stratiform or convective, and are generated by differences in temperature. When noted on weather radar imagery, this precipitation elongation is referred to as banded structure. Rainbands within tropical cyclones are curved in orientation. Rainbands of tropical cyclones contain showers and thunderstorms that, together with the eyewall and the eye, constitute a hurricane or tropical storm. The extent of rainbands around a tropical cyclone can help determine the cyclone's intensity. Rainbands spawned near and ahead of cold fronts can be squall lines which are able to produce tornadoes. Rainbands associated with cold fronts can be warped by mountain barriers perpendicular to the front's orientation due to the formation of a low-level barrier jet. Bands of thunderstorms can form with sea breeze and land breeze boundaries, if enough mois ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Altocumulus Cloud
Altocumulus (From Latin ''Altus'', "high", ''cumulus'', "heaped") is a middle-altitude cloud genus that belongs mainly to the ''stratocumuliform'' physical category characterized by globular masses or rolls in layers or patches, the individual elements being larger and darker than those of cirrocumulus and smaller than those of stratocumulus. However, if the layers become tufted in appearance due to increased airmass instability, then the altocumulus clouds become more purely ''cumuliform'' in structure. Like other cumuliform and stratocumuliform clouds, altocumulus signifies convection. A sheet of partially conjoined altocumulus perlucidus is sometimes found preceding a weakening warm front, where the altostratus is starting to fragment, resulting in patches of altocumulus perlucidus between the areas of altostratus. Altocumulus is also commonly found between the warm and cold fronts in a depression, although this is often hidden by lower clouds. Towering altocumulus, known as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Altostratus Cloud
Altostratus is a middle-altitude cloud genus made up of water droplets, ice crystals, or a mixture of the two. Altostratus clouds are formed when large masses of warm, moist air rise, causing water vapor to condense. Altostratus clouds are usually gray or blueish featureless sheets, although some variants have wavy or banded bases. The sun can be seen through thinner altostratus clouds, but thicker layers can be quite opaque. Altostratus clouds usually predict the arrival of warm fronts. Once altostratus clouds associated with a warm front arrive, continuous rain or snow will usually follow in the next 12 to 24 hours. Although altostratus clouds predict the arrival of warmer, wetter weather, they themselves do not produce significant precipitation. Thunderstorms can be embedded in altostratus clouds; however, bringing showers. Because altostratus clouds can contain ice crystals, they can produce some optical phenomena like iridescence and coronas. Description Altostratus c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
