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Cyclone Helen (2007)
Tropical Cyclone Helen was the first tropical cyclone to bring gale-force winds to Darwin, Northern Territory, Darwin, Australia since 1985. The fourth tropical cyclone naming, named storm of the 2007–08 Australian region cyclone season, Helen developed out of a weak low-pressure area, area of low pressure in late December over the Top End region of Australia. Generally tracking westward, the system eventually intensified into a tropical cyclone and was given the name Helen on 2 January. By this time, it was situated over the Joseph Bonaparte Gulf and was beginning to Retrograde motion#Within the atmosphere, retrograde eastward. Late on 4 January, the storm made landfall near Channel Point Coastal Reserve, Channel Point with winds of 95 km/h (60 mph) though rapidly weakened to a tropical low within 12 hours. Gradually accelerating, the remnants of Helen moved over the Gulf of Carpentaria before striking land again on 6 January. The system was last ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joseph Bonaparte Gulf
Joseph Bonaparte Gulf is a large body of water off the coast of the Northern Territory and Western Australia and part of the Timor Sea. It was named after Joseph Bonaparte, brother of Napoleon and King of Naples (1806–1808) and then Spain (1808–1813) by French explorer and naturalist Nicolas Baudin in 1803. It is also often referred to in Australia as the "Bonaparte Gulf". Description The Keep River and Victoria River drain into the gulf in the Northern Territory, the former close to the Western Australia – Northern Territory border. The Ord River, Pentecost River, Durack River, King River and the Forrest River drain into the Cambridge Gulf, another gulf within the southern part of the Joseph Bonaparte Gulf. The Legune (Joseph Bonaparte Bay) Important Bird Area lies at the south-eastern end of the gulf. The Bonaparte Basin is a large sedimentary basin underlying the gulf and a large part of the Timor Sea The Timor Sea (, , or ) is a relatively shallow sea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australian Dollar
The Australian dollar (currency sign, sign: $; ISO 4217, code: AUD; also abbreviated A$ or sometimes AU$ to distinguish it from other dollar, dollar-denominated currencies; and also referred to as the dollar or Aussie dollar) is the official currency and Legal tender#Australia, legal tender of Australia, including States and territories of Australia, all of its external territories, and three independent sovereign Pacific Islands, Pacific Island states: Kiribati, Nauru, and Tuvalu. * ThMoney Trackersite allows users to track Australian banknotes as they circulate around Australia. Images of historic and modern Australian bank notes* [https://www.rba.gov.au/statistics/historical-data.html?v=2022-09-25-02-11-35#exchange-rates Reserve Bank of Australia – historical data of AUD since 1969 (various .xls files)] The banknotes of Australia {{Authority control 1966 establishments in Australia Articles containing video clips Circulating currencies Currencies int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Convection
Atmospheric convection is the vertical transport of heat and moisture in the atmosphere. It occurs when warmer, less dense air rises, while cooler, denser air sinks. This process is driven by parcel-environment instability, meaning that a "parcel" of air is warmer and less dense than the surrounding environment at the same altitude. This difference in temperature and density (and sometimes humidity) causes the parcel to rise, a process known as buoyancy. This rising air, along with the compensating sinking air, leads to mixing, which in turn expands the height of the planetary boundary layer (PBL), the lowest part of the atmosphere directly influenced by the Earth's surface. This expansion contributes to increased winds, cumulus cloud development, and decreased surface dew points (the temperature below which condensation occurs). Convection plays a crucial role in weather patterns, influencing cloud formation, wind, and the development of thunderstorms, which can be associa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wind Shear
Wind shear (; also written windshear), sometimes referred to as wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizontal wind shear. Vertical wind shear is a change in wind speed or direction with a change in altitude. Horizontal wind shear is a change in wind speed with a change in lateral position for a given altitude. Wind shear is a microscale meteorological phenomenon occurring over a very small distance, but it can be associated with mesoscale or synoptic scale weather features such as squall lines and cold fronts. It is commonly observed near microbursts and downbursts caused by thunderstorms, fronts, areas of locally higher low-level winds referred to as low-level jets, near mountains, radiation inversions that occur due to clear skies and calm winds, buildings, wind turbines, and sailboats. Wind shear has significant effects on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inches Of Mercury
Inch of mercury (inHg, ″Hg, or in) is a non- SI unit of measurement for pressure. It is used for barometric pressure in weather reports, refrigeration and aviation in the United States. It is the pressure exerted by a column of mercury in height at the standard acceleration of gravity. Conversion to metric units depends on the density of mercury, and hence its temperature; typical conversion factors are: In older literature, an "inch of mercury" is based on the height of a column of mercury at .Barry N. Taylor, ''Guide for the Use of the International System of Units (SI),'' 1995, NIST Special Publication 811, Appendix /ref> :1 inHg60 °F = In Imperial units: 1 inHg60 °F = 0.489 771 Pounds per square inch, psi, or 2.041 771 inHg60 °F = 1 psi. Applications Aircraft and automobiles Aircraft altimeters measure the relative pressure difference between the lower ambient pressure at altitude and a calibrated reading on the ground ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pascal (unit)
The pascal (symbol: Pa) is the unit of pressure in the International System of Units (SI). It is also used to quantify internal pressure, stress, Young's modulus, and ultimate tensile strength. The unit, named after Blaise Pascal, is an SI coherent derived unit defined as one newton per square metre (N/m2). It is also equivalent to 10 barye (10 Ba) in the CGS system. Common multiple units of the pascal are the hectopascal (1 hPa = 100 Pa), which is equal to one millibar, and the kilopascal (1 kPa = 1000 Pa), which is equal to one centibar. The unit of measurement called '' standard atmosphere (atm)'' is defined as . Meteorological observations typically report atmospheric pressure in hectopascals per the recommendation of the World Meteorological Organization, thus a standard atmosphere (atm) or typical sea-level air pressure is about 1013 hPa. Reports in the United States typically use inches of mercury or millibars (hectopascals). In Cana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bar (unit)
The bar is a metric unit of pressure defined as 100,000 Pa (100 kPa), though not part of the International System of Units (SI). A pressure of 1 bar is slightly less than the current average atmospheric pressure on Earth at sea level (approximately 1.013 bar). By the barometric formula, 1 bar is roughly the atmospheric pressure on Earth at an altitude of 111 metres at 15 °C. The bar and the millibar were introduced by the Norwegian meteorologist Vilhelm Bjerknes, who was a founder of the modern practice of weather forecasting, with the bar defined as one megadyne per square centimetre. The SI brochure, despite previously mentioning the bar, now omits any mention of it.. The bar has been legally recognised in countries of the European Union since 2004. British Standard BS 350:2004 ''Conversion Factors for Units''. The US National Institute of Standards and Technology (NIST) deprecates its use except for "limited use in meteorology" and lists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barometric Pressure
Atmospheric pressure, also known as air pressure or barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1,013.25 millibars, 760 mm Hg, 29.9212 inchesHg, or 14.696 psi.International Civil Aviation Organization. ''Manual of the ICAO Standard Atmosphere'', Doc 7488-CD, Third Edition, 1993. . The atm unit is roughly equivalent to the mean sea-level atmospheric pressure on Earth; that is, the Earth's atmospheric pressure at sea level is approximately 1 atm. In most circumstances, atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point. As elevation increases, there is less overlying atmospheric mass, so atmospheric pressure decreases with increasing elevation. Because the atmosphere is thin relative to the Earth's radius—especially the dense atmospheric layer at low altitudes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trough (meteorology)
A trough is an elongated region of relatively low atmospheric pressure without a closed Isobar (meteorology), isobaric contour that would define it as a Low-pressure area, low pressure area. Since low pressure implies a low Geopotential height, height on a pressure surface, Valley, troughs and Ridge (meteorology), ridges refer to features in an identical sense as those on a topographic map. Troughs may be at the surface, or aloft, at altitude. Near-surface troughs sometimes mark a weather front associated with clouds, showers, and a wind direction shift. Upper-level troughs in the jet stream (as shown in diagram) reflect Cyclonic rotation, cyclonic filaments of vorticity. Their motion induces upper-level wind divergence, lifting and cooling the air ahead (downstream) of the trough and helping to produce cloudy and rain conditions there. Unlike fronts, there is not a universal symbol for a trough on a surface weather analysis chart. The weather charts in some countries or regions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tropical Cyclone Melanie (2007)
The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's axial tilt; the width of the tropics (in latitude) is twice the tilt. The tropics are also referred to as the tropical zone and the torrid zone (see geographical zone). Due to the overhead sun, the tropics receive the most solar energy over the course of the year, and consequently have the highest temperatures on the planet. Even when not directly overhead, the sun is still close to overhead throughout the year, therefore the tropics also have the lowest seasonal variation on the planet; "winter" and "summer" lose their temperature contrast. Instead, seasons are more commonly divided by precipitation variations than by temperature variations. The tropics maintain wide diversity of local climates, such as rain forests, monsoons, savannahs, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Madden–Julian Oscillation
The Madden–Julian oscillation (MJO) is the largest element of the intraseasonal (30- to 90-day) variability in the tropical atmosphere. It was discovered in 1971 by Roland Madden and Paul Julian of the American National Center for Atmospheric Research (NCAR). It is a large-scale coupling between atmospheric circulation and tropical deep atmospheric convection. Unlike a standing pattern like the El Niño–Southern Oscillation (ENSO), the Madden–Julian oscillation is a traveling pattern that propagates eastward, at approximately , through the atmosphere above the warm parts of the Indian and Pacific oceans. This overall circulation pattern manifests itself most clearly as anomalous rainfall. The Madden–Julian oscillation is characterized by an eastward progression of large regions of both enhanced and suppressed tropical rainfall, observed mainly over the Indian and Pacific Ocean. The anomalous rainfall is usually first evident over the western Indian Ocean, and remains e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Surface Temperature
Sea surface temperature (or ocean surface temperature) is the ocean temperature, temperature of ocean water close to the surface. The exact meaning of ''surface'' varies in the literature and in practice. It is usually between and below the sea surface. Sea surface temperatures greatly modify air masses in the Atmosphere of Earth, Earth's atmosphere within a short distance of the shore. The thermohaline circulation has a major impact on average sea surface temperature throughout most of the world's oceans. Warm sea surface temperatures can develop and Tropical cyclogenesis, strengthen cyclones over the ocean. Tropical cyclones can also cause a cool wake. This is due to turbulent mixing of the upper of the ocean. Sea surface temperature changes during the day. This is like the air above it, but to a lesser degree. There is less variation in sea surface temperature on breezy days than on calm days. Coastal sea surface temperatures can cause offshore winds to generate upwelling ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
