|
Held–Hou Model
The Held–Hou Model is a model for the Hadley circulation of the atmosphere that would exist in the absence of atmospheric turbulence. The model was developed by Isaac Held and Arthur Hou in 1980. The essence of the model is that air rising from the surface at the equator conserves its angular momentum as it moves poleward. This distribution of wind, in turn, determines the distribution of temperature, which determines the latitudinal extent of the circulation by requiring energy conservation. This stands in contrast to George Hadley's original conception of the circulation, which he argued reached the poles. The Hadley circulation has a cooling effect at and near the equator and a warming effect at higher latitudes within the Hadley cell. This energy transport can be converted into a mass transport, to determine the strength of the circulation, by normalizing by the appropriate vertical stability. The effects of moisture and seasons A season is a division of the year based on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hadley Circulation
The Hadley cell, also known as the Hadley circulation, is a global-scale tropical atmospheric circulation that features air rising near the equator, flowing poleward near the tropopause at a height of above the Earth's surface, cooling and descending in the subtropics at around 25 degrees latitude, and then returning equatorward near the surface. It is a thermally direct circulation within the troposphere that emerges due to differences in insolation and heating between the tropics and the subtropics. On a yearly average, the circulation is characterized by a circulation cell on each side of the equator. The Southern Hemisphere Hadley cell is slightly stronger on average than its northern counterpart, extending slightly beyond the equator into the Northern Hemisphere. During the summer and winter months, the Hadley circulation is dominated by a single, cross-equatorial cell with air rising in the summer hemisphere and sinking in the winter hemisphere. Analogous circulations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isaac Held
Isaac Meyer Held (born October 23, 1948) is an American meteorologist. He is a retired senior research scientist at the Geophysical Fluid Dynamics Laboratory. Held was elected to the United States National Academy of Sciences in 2003. Biography Born to refugee parents in Ulm, Germany in 1948, Held came to Minnesota with his family at the age of 4. His father died when he was only eight and he and his brother, Herman, were raised by his mother Bertha, a Holocaust survivor who worked as a seamstress. Held did his undergraduate work in physics at the University of Minnesota, Minneapolis in 1969 and started a graduate program in theoretical physics at the State University of New York at Stony Brook. Isaac and his wife, Joann, have one son, Joshua. While there, he discovered climate science which led to his transferring to the Atmospheric and Oceanic Sciences Program at Princeton University, where he completed his Ph.D. in 1976 under the supervision of Syukuro Manabe. After a brief s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angular Momentum
Angular momentum (sometimes called moment of momentum or rotational momentum) is the rotational analog of Momentum, linear momentum. It is an important physical quantity because it is a Conservation law, conserved quantity – the total angular momentum of a closed system remains constant. Angular momentum has both a direction (geometry), direction and a magnitude, and both are conserved. Bicycle and motorcycle dynamics, Bicycles and motorcycles, flying discs, Rifling, rifled bullets, and gyroscopes owe their useful properties to conservation of angular momentum. Conservation of angular momentum is also why hurricanes form spirals and neutron stars have high rotational rates. In general, conservation limits the possible motion of a system, but it does not uniquely determine it. The three-dimensional angular momentum for a point particle is classically represented as a pseudovector , the cross product of the particle's position vector (relative to some origin) and its mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Energy Conservation
Energy conservation is the effort to reduce wasteful energy consumption by using fewer energy services. This can be done by using energy more effectively (using less and better sources of energy for continuous service) or changing one's behavior to use less and better source of service (for example, by driving vehicles which consume renewable energy or energy with more efficiency). Energy conservation can be achieved through efficient energy use, which has some advantages, including a reduction in greenhouse gas emissions and a smaller carbon footprint, as well as cost, water, and energy savings. Green engineering practices improve the life cycle of the components of machines which convert energy from one form into another. Energy can be conserved by reducing waste and losses, improving efficiency through technological upgrades, improving operations and maintenance, changing users' behaviors through user profiling or user activities, monitoring appliances, shifting load to o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
George Hadley
George Hadley (12 February 1685 – 28 June 1768) was an English lawyer and amateur meteorologist who proposed the atmospheric mechanism by which the trade winds are sustained, which is now named in his honour as Hadley circulation. As a key factor in ensuring that European sailing vessels reached North American shores, understanding the trade winds was becoming a matter of great importance at the time. Hadley was intrigued by the fact that winds which should by all rights have blown straight north had a pronounced westerly flow, and it was this mystery he set out to solve. Life Hadley was born in London, England to George Hadley ( High Sheriff of Hertfordshire) and Katherine FitzJames. He had an unremarkable childhood, and was eclipsed in his early years by his older brother John Hadley (1682–1744), the inventor of the octant (a precursor to the sextant). With John and his other brother Henry, George had constructed effective Newtonian telescopes. George Hadley entered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equator
The equator is the circle of latitude that divides Earth into the Northern Hemisphere, Northern and Southern Hemisphere, Southern Hemispheres of Earth, hemispheres. It is an imaginary line located at 0 degrees latitude, about in circumference, halfway between the North Pole, North and South Pole, South poles. The term can also be used for any other celestial body that is roughly spherical. In three-dimensional space, spatial (3D) geometry, as applied in astronomy, the equator of a rotating spheroid (such as a planet) is the parallel (circle of latitude) at which latitude is defined to be 0°. It is an imaginary line on the spheroid, equidistant from its geographical pole, poles, dividing it into northern and southern hemispheres. In other words, it is the intersection of the spheroid with the plane (geometry), plane perpendicular to its axis of rotation and midway between its geographical poles. On and near the equator (on Earth), noontime sunlight appears almost directly o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latitude
In geography, latitude is a geographic coordinate system, geographic coordinate that specifies the north-south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from −90° at the south pole to 90° at the north pole, with 0° at the Equator. Parallel (latitude), Lines of constant latitude, or ''parallels'', run east-west as circles parallel to the equator. Latitude and longitude are used together as a coordinate pair to specify a location on the surface of the Earth. On its own, the term "latitude" normally refers to the ''geodetic latitude'' as defined below. Briefly, the geodetic latitude of a point is the angle formed between the vector perpendicular (or ''Normal (geometry), normal'') to the ellipsoidal surface from the point, and the equatorial plane, plane of the equator. Background Two levels of abstraction are employed in the definitions of latitude and longitude. In the first step the physical surface i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hadley Cell
The Hadley cell, also known as the Hadley circulation, is a global-scale tropical atmospheric circulation that features air rising near the equator, flowing poleward near the tropopause at a height of above the Earth's surface, cooling and descending in the subtropics at around 25 degrees latitude, and then returning equatorward near the surface. It is a thermally direct circulation within the troposphere that emerges due to differences in insolation and heating between the tropics and the subtropics. On a yearly average, the circulation is characterized by a circulation cell on each side of the equator. The Southern Hemisphere Hadley cell is slightly stronger on average than its northern counterpart, extending slightly beyond the equator into the Northern Hemisphere. During the summer and winter months, the Hadley circulation is dominated by a single, cross-equatorial cell with air rising in the summer hemisphere and sinking in the winter hemisphere. Analogous circulations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moisture
Moisture is the presence of a liquid, especially water, often in trace amounts. Moisture is defined as water in the adsorbed or absorbed phase. Small amounts of water may be found, for example, in the air (humidity), in foods, and in some commercial products. Moisture also refers to the amount of water vapor present in the air. The soil also includes moisture. Moisture control in products Control of moisture in products can be a vital part of the process of the product. There is a substantial amount of moisture in what seems to be dry matter. Ranging in products from cornflake cereals to laundry detergent, washing powders, moisture can play an important role in the final quality of the product. There are two main aspects of concern in moisture control in products: allowing too much moisture or too little of it. For example, adding some water to cornflake cereal, which is sold by weight, reduces costs and prevents it from tasting too dry, but adding too much water can affect th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seasons
A season is a division of the year based on changes in weather, ecology, and the number of daylight hours in a given region. On Earth, seasons are the result of the axial parallelism of Earth's axial tilt, tilted orbit around the Sun. In temperate and polar regions, the seasons are marked by changes in the intensity of sunlight that reaches the Earth's surface, variations of which may cause animals to undergo hibernation or to Migration (ecology), migrate, and plants to be dormant. Various cultures define the number and nature of seasons based on regional variations, and as such there are a number of both modern and historical definitions of the seasons. The Northern Hemisphere experiences most direct sunlight during May, June, and July (thus the traditional celebration of Midsummer in June), as the hemisphere faces the Sun. For the Southern Hemisphere it is instead in November, December, and January. It is Earth's axial tilt that causes the Sun to be higher in the sky during the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
