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BWER On Radar Data
The bounded weak echo region, also known as a BWER or a vault, is a radar signature within a thunderstorm characterized by a local minimum in radar reflectivity at low levels which extends upward into, and is surrounded by, higher reflectivities aloft. This feature is associated with a strong updraft and is almost always found in the inflow region of a thunderstorm. It cannot be seen visually. The BWER has been noted on radar imagery of severe thunderstorms since 1973 and has a lightning detection system equivalent known as a ''lightning hole''.Martin J. Murphy and Nicholas W. S. DemetriadesAn Analysis of Lightning Holes in a DFW Supercell Storm Using Total Lightning and Radar Information.Retrieved on 2008-01-08. Description and attributes The BWER is a nearly vertical channel of weak radar echo, surrounded on the sides and top by significantly stronger echoes. The BWER, sometimes called a vault, is related to the strong updraft in a severe convective storm that carries newly fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BWER On Radar Data
The bounded weak echo region, also known as a BWER or a vault, is a radar signature within a thunderstorm characterized by a local minimum in radar reflectivity at low levels which extends upward into, and is surrounded by, higher reflectivities aloft. This feature is associated with a strong updraft and is almost always found in the inflow region of a thunderstorm. It cannot be seen visually. The BWER has been noted on radar imagery of severe thunderstorms since 1973 and has a lightning detection system equivalent known as a ''lightning hole''.Martin J. Murphy and Nicholas W. S. DemetriadesAn Analysis of Lightning Holes in a DFW Supercell Storm Using Total Lightning and Radar Information.Retrieved on 2008-01-08. Description and attributes The BWER is a nearly vertical channel of weak radar echo, surrounded on the sides and top by significantly stronger echoes. The BWER, sometimes called a vault, is related to the strong updraft in a severe convective storm that carries newly fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weather Radar
Weather radar, also called weather surveillance radar (WSR) and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, and estimate its type (rain, snow, hail etc.). Modern weather radars are mostly pulse-Doppler radars, capable of detecting the motion of rain droplets in addition to the intensity of the precipitation. Both types of data can be analyzed to determine the structure of storms and their potential to cause severe weather. During World War II, radar operators discovered that weather was causing echoes on their screen, masking potential enemy targets. Techniques were developed to filter them, but scientists began to study the phenomenon. Soon after the war, surplus radars were used to detect precipitation. Since then, weather radar has evolved on its own and is now used by national weather services, research departments in universities, and in television stations' weather departments. Raw images are routinely used and speciali ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convective Storm Detection
Convective storm detection is the meteorological observation, and short-term prediction, of deep moist convection (DMC). DMC describes atmospheric conditions producing single or clusters of large vertical extension clouds ranging from cumulus congestus to cumulonimbus, the latter producing thunderstorms associated with lightning and thunder. Those two types of clouds can produce severe weather at the surface and aloft. The ability to discern the presence of deep moist convection in a storm significantly improves meteorologists' capacity to predict and monitor associated phenomena such as tornadoes, large hail, strong winds, and heavy rain leading to flash flooding. It relies on direct eyewitness observations, for example from storm spotters; and on remote sensing, especially weather radar. Some in situ measurements are used for direct detection as well, notably, wind speed reports from surface observation stations. It is part of the ''integrated warning system'', consisting of p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Three Body Scatter Spike
A hail spike or three body scatter spike (TBSS) is an artifact on a weather radar display indicative of large hail. They are identified by a spike of weak reflectivity echoes that extend out from a thunderstorm, and away from the radar site. Cause Generally known as hail spikes, these are the result of energy from the radar hitting hail, or very heavy rain, and being reflected to the ground, where they reflect back to the hail and then to the radar as in the image on the left. This results in the radar picking up the energy from the multiple path at a later time than the energy that came back directly from the hail to the radar. Both are however on the same radial angle from the radar as the antenna did not have the time to turn significantly. The multipath echoes are then analyzed on the radar display as echoes extending in a radial direction behind the actual location of the hail/heavy rain core. The loss of energy by due to multiple reflections means weaker return echoes. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hook Echo
A hook echo is a pendant or hook-shaped weather radar signature as part of some supercell thunderstorms. It is found in the lower portions of a storm as air and precipitation flow into a mesocyclone, resulting in a curved feature of reflectivity. The echo is produced by rain, hail, or even debris being wrapped around the supercell. It is one of the classic hallmarks of tornado-producing supercells. The National Weather Service may consider the presence of a hook echo coinciding with a tornado vortex signature as sufficient to justify issuing a tornado warning. History Because of the unpredictable and potentially catastrophic nature of tornadoes, the possibility of detecting tornadoes via radar was discussed in the meteorological community in the earliest days of meteorological radar.Huff, F.A., H.W. Hiser, and S.G. Bigler, 1954Study of an Illinois tornado using radar, synoptic weather and field survey data Report of Investigation 22, Champaign, IL, pp. 73 The first association bet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tornadogenesis
Tornadogenesis is the process by which a tornado forms. There are many types of tornadoes and these vary in methods of formation. Despite ongoing scientific study and high-profile research projects such as VORTEX, tornadogenesis is a volatile process and the intricacies of many of the mechanisms of tornado formation are still poorly understood. A tornado is a violently rotating column of air in contact with the surface and a cumuliform cloud base. Tornado formation is caused by the stretching and aggregating/merging of environmental and/or storm-induced vorticity that tightens it into an intense vortex. There are various ways this may come about and thus various forms and sub-forms of tornadoes. Although each tornado is unique, most kinds of tornadoes go through a life cycle of formation, maturation, and dissipation. The process by which a tornado dissipates or decays, occasionally conjured as tornadolysis, is of particular interest for study as is tornadogenesis, longevity, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tornado
A tornado is a violently rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, although the word cyclone is used in meteorology to name a weather system with a low-pressure area in the center around which, from an observer looking down toward the surface of the Earth, winds blow counterclockwise in the Northern Hemisphere and clockwise in the Southern. Tornadoes come in many shapes and sizes, and they are often visible in the form of a condensation funnel originating from the base of a cumulonimbus cloud, with a cloud of rotating debris and dust beneath it. Most tornadoes have wind speeds less than , are about across, and travel several kilometers (a few miles) before dissipating. The most extreme tornadoes can attain wind speeds of more than , are more than in diameter, and stay on the ground for more than 100 k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Storm Prediction Center
The Storm Prediction Center (SPC) is a US government agency A government or state agency, sometimes an appointed commission, is a permanent or semi-permanent organization in the machinery of government that is responsible for the oversight and administration of specific functions, such as an administrati ... that is part of the National Centers for Environmental Prediction (NCEP), operating under the control of the National Weather Service (NWS), which in turn is part of the National Oceanic and Atmospheric Administration (NOAA) of the United States Department of Commerce (DoC). Headquartered at the National Weather Center in Norman, Oklahoma, Norman, Oklahoma, the Storm Prediction Center is tasked with forecasting the risk of severe thunderstorms and tornadoes in the contiguous United States. It issues #Convective outlooks, convective outlooks, #Mesoscale discussions, mesoscale discussions, and #Weather watches, watches as a part of this process. Convective outlooks are issu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plan Position Indicator
A plan position indicator (PPI) is a type of radar display that represents the radar antenna in the center of the display, with the distance from it and height above ground drawn as concentric circles. As the radar antenna rotates, a radial trace on the PPI sweeps in unison with it about the center point. It is the most common type of radar display. Description The radar antenna sends pulses while rotating 360 degrees around the radar site at a fixed elevation angle. It can then change angle or repeat at the same angle according to the need. Return echoes from targets are received by the antenna and processed by the receiver and the most direct display of those data is the PPI. The height of the echoes increases with the distance to the radar, as represented in the adjacent image. This change is not a straight line but a curve as the surface of the Earth is curved and ''sinks'' below the radar horizon. For fixed-site installations, north is usually represented at the top of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wayback Machine
The Wayback Machine is a digital archive of the World Wide Web founded by the Internet Archive, a nonprofit based in San Francisco, California. Created in 1996 and launched to the public in 2001, it allows the user to go "back in time" and see how websites looked in the past. Its founders, Brewster Kahle and Bruce Gilliat, developed the Wayback Machine to provide "universal access to all knowledge" by preserving archived copies of defunct web pages. Launched on May 10, 1996, the Wayback Machine had more than 38.2 million records at the end of 2009. , the Wayback Machine had saved more than 760 billion web pages. More than 350 million web pages are added daily. History The Wayback Machine began archiving cached web pages in 1996. One of the earliest known pages was saved on May 10, 1996, at 2:08p.m. Internet Archive founders Brewster Kahle and Bruce Gilliat launched the Wayback Machine in San Francisco, California, in October 2001, primarily to address the problem of web co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by total area. Its southern and western border with the United States, stretching , is the world's longest binational land border. Canada's capital is Ottawa, and its three largest metropolitan areas are Toronto, Montreal, and Vancouver. Indigenous peoples have continuously inhabited what is now Canada for thousands of years. Beginning in the 16th century, British and French expeditions explored and later settled along the Atlantic coast. As a consequence of various armed conflicts, France ceded nearly all of its colonies in North America in 1763. In 1867, with the union of three British North American colonies through Confederation, Canada was formed as a federal dominion of four provinces. This began an accretion of provinces an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
McGill University
McGill University (french: link=no, Université McGill) is an English-language public research university located in Montreal, Quebec, Canada. Founded in 1821 by royal charter granted by King George IV,Frost, Stanley Brice. ''McGill University, Vol. I. For the Advancement of Learning, 1801–1895.'' McGill-Queen's University Press, 1980. the university bears the name of James McGill, a Scottish merchant whose bequest in 1813 formed the university's precursor, University of McGill College (or simply, McGill College); the name was officially changed to McGill University in 1885. McGill's main campus is on the slope of Mount Royal in downtown Montreal in the borough of Ville-Marie, with a second campus situated in Sainte-Anne-de-Bellevue, west of the main campus on Montreal Island. The university is one of two members of the Association of American Universities located outside the United States, alongside the University of Toronto, and is the only Canadian member of the Glob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
