Why does it get so HOT? I have brought in the experts for the answers: Google Index and Wikipedia! There are many contributing factors to the Hot Weather. You will personally be affected (or not) by your Location to the moving Heat. At my location today, it was 110 degrees, which is too hot to handle. Your photostudy tonight is the huge ball of fire setting for the night! Your infostudy is on High Pressure and Earth Facts about the Earth's Heat and the movement of Hot Air on the Surface. Enjoy!!
http://en.wikipedia.org/wiki/High-pressure_area
High-pressure area
From Wikipedia, the free encyclopedia
A high-pressure area, high or anticyclone is a region where the atmospheric pressure at the surface of the planet is greater than its surrounding environment.
Winds within high-pressure areas flow outward from the higher pressure areas near their centers towards the lower pressure areas further from their centers. Gravity adds to the forces causing this general movement, because the higher pressure compresses the column of air near the center of the area into greater density – and so greater weight compared to lower pressure, lower density, and lower weight of the air outside the center.
However, because the planet is rotating underneath the atmosphere, and frictional forces arise as the planetary surface drags some atmosphere with it, the air flow from center to periphery is not direct, but is twisted due to the Coriolis effect, or the merely apparent force that arise when the observer is in a rotating frame of reference. Viewed from above this twist in wind direction is in the same direction as the rotation of the planet.
The strongest high-pressure areas are associated with cold air masses which push away out of polar regions during the winter when there is less sun to warm neighboring regions. These Highs change character and weaken once they move further over relatively warmer water bodies.
Somewhat weaker but more common are high pressure areas caused by atmospheric subsidence, that is, areas where large masses of cooler drier air descends from an elevation of 8 to 15 km after the lower temperatures has precipitated out the lighter water vapor. (H2O is about half of the molecular weight of the other two main constituents of the atmosphere—Oxygen, O2, and Nitrogen, N2.)
Many of the features of Highs may be understood in context of middle- or meso-scale and relatively enduring dynamics of a planet's atmospheric circulation. For example, massive atmospheric subsidences occur as part of the descending branches of Ferrel cells and Hadley cells. Hadley cells help form the subtropical ridge, steer tropical waves and tropical cyclones across the ocean and is strongest during the summer. The subtropical ridge also helps form most of the world's deserts.
On English-language weather maps, high-pressure centers are identified by the letter H. Weather maps in other languages may use different letters or symbols.
Wind Circulation in the northern and southern hemispheres[edit]
The direction of wind flow around a High (and, contrarily for a Low) depends on the hemisphere. With two wind directions (following the right- or left-hand rule), two pressure conditions (High or Low), and two hemispheres (northern or southern), it's easy to be confused. Adding to the confusion can be the many different words in use to describe the underlying physical realities.
The scientific terms in English used to describe the weather systems generated by Highs (and Lows) were introduced in the mid-1800s, mostly by Brits. The scientific theories which explain the general phenomena originated two centuries earlier.
Anticyclone—the term for the kind of winter storm around a polar High in the northern hemisphere—was coined in 1877 by Francis Galton[2] to indicate a storm whose winds revolved in the opposite direction of a cyclone. The term Cyclone was coined by an official of the British East India Company to describe an especially destructive storm in Coringa, India during the Indian Ocean cyclone season at the end of 1789.[3]
That "first"-dubbed cyclone of 1789 formed around a northern hemispheric Low (often a Tropical cyclone) and so must have turned clockwise. In British English of the time, the opposite direction of clockwise was often called anticlockwise, making the label for the anticlockwise rotations of northern anticyclones a logical extension.
In describing the spin, twist, or orientation of many diverse (and even higher-dimensional) physical phenomena, scientists often take the three-dimensional human body as the standard model, rather than, say, 2D clock movements. The right-hand rule refers to the immediately available observation that the right-hand fist with the thumb extended upward leaves the fingers curled in a counter-clockwise direction. This is the right-orientation, also the direction of rotation of the earth, moving east to west, when seen from above the north pole. And, again, it is the direction of winds around High-pressure areas.
A simple rule of thumb is that for Highs, where generally air flows from the center outward, the twist given by the earth's rotation to the air circulation is in the same direction as earth's apparent rotation if viewed from above the hemisphere's pole. So, both the earth and winds around a High rotate right (right-hand rule) in the norther hemisphere, and left in the southern. The opposite to these two cases occurs in the two cases of a Low. Both results derive from the Coriolis effect; that article explains in detail the physics, and provides an animation of a model to aid understanding.
Formation[edit]
Main article: Anticyclogenesis
High-pressure systems form due to downward motion through the troposphere, the atmospheric layer where weatheroccurs. 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, and about half the atmospheric pressure at the surface.[4][5]
High-pressure systems are alternatively referred to as anticyclones. On English-language weather maps, high-pressure centers are identified by the letter H in English,[6] within the isobar with the highest pressure value. On constant pressure upper level charts, it is located within the highest height line contour.[7]
Typical conditions[edit]
Highs are frequently associated with light winds at the surface and subsidence through the lower portion of thetroposphere. In general, subsidence will dry out an air mass by adiabatic, or compressional, heating.[8] Thus, high pressure typically brings clear skies.[9] During the day, since no clouds are present to reflect sunlight, there is more incoming shortwave solar radiation and temperatures rise. At night, the absence of clouds means that outgoinglongwave radiation (i.e. heat energy from the surface) is not absorbed, giving cooler diurnal low temperatures in all seasons. When surface winds become light, the subsidence produced directly under a high-pressure system can lead to a build up of particulates in urban areas under the ridge, leading to widespread haze.[10] If the low level relative humidity rises towards 100 percent overnight, fog can form.[11]
Strong, vertically shallow high-pressure systems moving from higher latitudes to lower latitudes in the northern hemisphere are associated with continental arctic air masses.[12] Once arctic air moves over an unfrozen ocean, the air mass modifies greatly over the warmer water and takes on the character of a maritime air mass, which reduces the strength of the high-pressure system.[13] When extremely cold air moves over relatively warm oceans, polar lows can develop.[14] However, warm and moist (or maritime tropical) air masses that move poleward from tropical sources are slower to modify than arctic air masses
The following is an excerpt only from the large Wikipedia Page on Earth. Please visit link for complete item:
http://en.wikipedia.org/wiki/Earth
Earth
From Wikipedia, the free encyclopedia
 "The Blue Marble" photograph of Earth, taken from Apollo 17 | |
Heat
Earth's internal heat comes from a combination of residual heat from planetary accretion (about 20%) and heat produced through radioactive decay (80%).[83] The major heat-producing isotopes in the Earth are potassium-40, uranium-238, uranium-235, and thorium-232.[84] At the center of the planet, the temperature may be up to6,000 °C (10,830 °F),[85] and the pressure could reach 360 GPa.[86] Because much of the heat is provided by radioactive decay, scientists believe that early in Earth history, before isotopes with short half-lives had been depleted, Earth's heat production would have been much higher. This extra heat production, twice present-day at approximately 3 byr,[83] would have increased temperature gradients within the Earth, increasing the rates of mantle convection and plate tectonics, and allowing the production of igneous rocks such as komatiites that are not formed today.[87]
| Isotope | Heat release Wkg isotope | Half-life years | Mean mantle concentration kg isotopekg mantle | Heat release Wkg mantle |
|---|---|---|---|---|
| 238U | 9.46 × 10−5 | 4.47 × 109 | 30.8 × 10−9 | 2.91 × 10−12 |
| 235U | 5.69 × 10−4 | 7.04 × 108 | 0.22 × 10−9 | 1.25 × 10−13 |
| 232Th | 2.64 × 10−5 | 1.40 × 1010 | 124 × 10−9 | 3.27 × 10−12 |
| 40K | 2.92 × 10−5 | 1.25 × 109 | 36.9 × 10−9 | 1.08 × 10−12 |
The mean heat loss from the Earth is 87 mW m−2, for a global heat loss of 4.42 × 1013 W.[89] A portion of the core's thermal energy is transported toward the crust bymantle plumes; a form of convection consisting of upwellings of higher-temperature rock. These plumes can produce hotspots and flood basalts.[90] More of the heat in the Earth is lost through plate tectonics, by mantle upwelling associated with mid-ocean ridges. The final major mode of heat loss is through conduction through the lithosphere, the majority of which occurs in the oceans because the crust there is much thinner than that of the continents.[91]
Surface
Main articles: Landform and Extreme points of Earth
The Earth's terrain varies greatly from place to place. About 70.8%[13] of the surface is covered by water, with much of the continental shelf below sea level. This equates to 361.132 million km2 (139.43 million sq mi).[100] The submerged surface has mountainous features, including a globe-spanning mid-ocean ridge system, as well as undersea volcanoes,[69] oceanic trenches, submarine canyons, oceanic plateaus and abyssal plains. The remaining 29.2% (148.94 million km2, or 57.51 million sq mi) not covered by water consists of mountains, deserts, plains, plateaus, and other geomorphologies.
The planetary surface undergoes reshaping over geological time periods due to tectonics and erosion. The surface features built up or deformed through plate tectonics are subject to steady weathering from precipitation, thermal cycles, and chemical effects. Glaciation, coastal erosion, the build-up of coral reefs, and large meteorite impacts[101] also act to reshape the landscape.
The continental crust consists of lower density material such as the igneous rocks granite and andesite. Less common is basalt, a denser volcanic rock that is the primary constituent of the ocean floors.[102] Sedimentary rock is formed from the accumulation of sediment that becomes compacted together. Nearly 75% of the continental surfaces are covered by sedimentary rocks, although they form only about 5% of the crust.[103] The third form of rock material found on Earth is metamorphic rock, which is created from the transformation of pre-existing rock types through high pressures, high temperatures, or both. The most abundant silicate minerals on the Earth's surface include quartz, the feldspars, amphibole, mica, pyroxene and olivine.[104] Common carbonate minerals include calcite (found in limestone) and dolomite.[105]
The pedosphere is the outermost layer of the Earth that is composed of soil and subject to soil formation processes. It exists at the interface of the lithosphere, atmosphere, hydrosphere and biosphere. Currently the total arable land is 13.31% of the land surface, with only 4.71% supporting permanent crops.[14] Close to 40% of the Earth's land surface is presently used for cropland and pasture, or an estimated 1.3×107 km2 of cropland and 3.4×107 km2 of pastureland.[106]
The elevation of the land surface of the Earth varies from the low point of −418 m at the Dead Sea, to a 2005-estimated maximum altitude of 8,848 m at the top of Mount Everest. The mean height of land above sea level is 840 m.[107]
Besides being divided logically into Northern and Southern Hemispheres centered on the earths poles, the earth has been divided arbitrarily into Eastern and Western Hemispheres.
Hydrosphere
Main article: Hydrosphere
The abundance of water on Earth's surface is a unique feature that distinguishes the "Blue Planet" from others in the Solar System. The Earth's hydrosphere consists chiefly of the oceans, but technically includes all water surfaces in the world, including inland seas, lakes, rivers, and underground waters down to a depth of 2,000 m. The deepest underwater location is Challenger Deep of the Mariana Trench in the Pacific Ocean with a depth of −10,911.4 m.[note 11][108]
The mass of the oceans is approximately 1.35×1018 metric tons, or about 1/4400 of the total mass of the Earth. The oceans cover an area of 3.618×108 km2 with a mean depth of 3,682 m, resulting in an estimated volume of 1.332×109 km3.[109] If all the land on Earth were spread evenly, water would rise to an altitude of more than 2.7 km.[note 12] About 97.5% of the water is saline, while the remaining 2.5% is fresh water. Most fresh water, about 68.7%, is currently ice.[110]
The average salinity of the Earth's oceans is about 35 grams of salt per kilogram of sea water (35 ‰ salt).[111]Most of this salt was released from volcanic activity or extracted from cool, igneous rocks.[112] The oceans are also a reservoir of dissolved atmospheric gases, which are essential for the survival of many aquatic life forms.[113] Sea water has an important influence on the world's climate, with the oceans acting as a large heat reservoir.[114] Shifts in the oceanic temperature distribution can cause significant weather shifts, such as the El Niño-Southern Oscillation.[115]
Atmosphere
Main article: Atmosphere of Earth
The atmospheric pressure on the surface of the Earth averages 101.325 kPa, with a scale height of about 8.5 km.[3] It is 78% nitrogen and 21% oxygen, with trace amounts of water vapor, carbon dioxide and other gaseous molecules. The height of thetroposphere varies with latitude, ranging between 8 km at the poles to 17 km at the equator, with some variation resulting from weather and seasonal factors.[117]
Earth's biosphere has significantly altered its atmosphere. Oxygenic photosynthesis evolved 2.7 bya, forming the primarily nitrogen–oxygen atmosphere of today. This change enabled the proliferation of aerobic organisms as well as the formation of the ozone layer which blocks ultraviolet solar radiation, permitting life on land. Other atmospheric functions important to life on Earth include transporting water vapor, providing useful gases, causing small meteors to burn up before they strike the surface, and moderating temperature.[118] This last phenomenon is known as the greenhouse effect: trace molecules within the atmosphere serve to capture thermal energy emitted from the ground, thereby raising the average temperature. Water vapor, carbon dioxide, methane and ozone are the primary greenhouse gases in the Earth's atmosphere. Without this heat-retention effect, the average surface would be −18 °C, in contrast to the current +15 °C, and life would likely not exist.[119]
Weather and climate
The Earth's atmosphere has no definite boundary, slowly becoming thinner and fading into outer space. Three-quarters of the atmosphere's mass is contained within the first 11 km of the planet's surface. This lowest layer is called the troposphere. Energy from the Sun heats this layer, and the surface below, causing expansion of the air. This lower-density air then rises, and is replaced by cooler, higher-density air. The result is atmospheric circulation that drives the weather and climate through redistribution of thermal energy.[120]
The primary atmospheric circulation bands consist of the trade winds in the equatorial region below 30° latitude and thewesterlies in the mid-latitudes between 30° and 60°.[121] Ocean currents are also important factors in determining climate, particularly the thermohaline circulation that distributes thermal energy from the equatorial oceans to the polar regions.[122]
Water vapor generated through surface evaporation is transported by circulatory patterns in the atmosphere. When atmospheric conditions permit an uplift of warm, humid air, this water condenses and settles to the surface asprecipitation.[120] Most of the water is then transported to lower elevations by river systems and usually returned to the oceans or deposited into lakes. This water cycle is a vital mechanism for supporting life on land, and is a primary factor in the erosion of surface features over geological periods. Precipitation patterns vary widely, ranging from several meters of water per year to less than a millimeter. Atmospheric circulation, topological features and temperature differences determine the average precipitation that falls in each region.[123]
The amount of solar energy reaching the Earth's decreases with increasing latitude. At higher latitudes the sunlight reaches the surface at lower angles and it must pass through thicker columns of the atmosphere. As a result, the mean annual air temperature at sea level decreases by about 0.4 °C per degree of latitude away from the equator.[124] The Earth can be subdivided into specific latitudinal belts of approximately homogeneous climate. Ranging from the equator to the polar regions, these are the tropical (or equatorial), subtropical, temperate and polar climates.[125] Climate can also be classified based on the temperature and precipitation, with the climate regions characterized by fairly uniform air masses. The commonly used Köppen climate classification system (as modified by Wladimir Köppen's student Rudolph Geiger) has five broad groups (humid tropics, arid, humid middle latitudes, continental and cold polar), which are further divided into more specific subtypes.[121]
Upper atmosphere
See also: Outer space
Above the troposphere, the atmosphere is usually divided into the stratosphere, mesosphere, and thermosphere.[118] Each layer has a different lapse rate, defining the rate of change in temperature with height. Beyond these, the exosphere thins out into the magnetosphere, where the Earth's magnetic fields interact with the solar wind.[126] Within the stratosphere is the ozone layer, a component that partially shields the surface from ultraviolet light and thus is important for life on Earth. TheKármán line, defined as 100 km above the Earth's surface, is a working definition for the boundary between atmosphere and space.[127]
Thermal energy causes some of the molecules at the outer edge of the Earth's atmosphere to increase their velocity to the point where they can escape from the planet's gravity. This causes a slow but steady leakage of the atmosphere into space. Because unfixed hydrogen has a low molecular weight, it can achieve escape velocity more readily and it leaks into outer space at a greater rate than other gasses.[128] The leakage of hydrogen into space contributes to the pushing of the Earth from an initially reducing state to its current oxidizing one. Photosynthesis provided a source of free oxygen, but the loss of reducing agents such as hydrogen is believed to have been a necessary precondition for the widespread accumulation of oxygen in the atmosphere.[129] Hence the ability of hydrogen to escape from the Earth's atmosphere may have influenced the nature of life that developed on the planet.[130] In the current, oxygen-rich atmosphere most hydrogen is converted into water before it has an opportunity to escape. Instead, most of the hydrogen loss comes from the destruction of methane in the upper atmosphere.[131]
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