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94-562: The Earth's weather is a consequence of its illumination by the Sun and the laws of thermodynamics . The atmospheric circulation can be viewed as a heat engine driven by the Sun's energy and whose energy sink , ultimately, is the blackness of space. The work produced by that engine causes the motion of the masses of air, and in that process it redistributes the energy absorbed by the Earth's surface near

188-634: A tectonic uplift can significantly alter their major elements, such as the jet stream , and plate tectonics may shift ocean currents . During the extremely hot climates of the Mesozoic , a third desert belt may have existed at the Equator . The wind belts girdling the planet are organised into three cells in each hemisphere—the Hadley cell , the Ferrel cell, and the polar cell. Those cells exist in both

282-467: A Reynolds averaging of the Navier–Stokes equations , are modelled by a linear constitutive relationship with the mean flow straining field, as: where Hemodynamics is the study of blood flow in the circulatory system. Blood flow in straight sections of the arterial tree are typically laminar (high, directed wall stress), but branches and curvatures in the system cause turbulent flow. Turbulent flow in

376-515: A cool breeze from the sea that replaces the risen air. At night, the relatively warmer water and cooler land reverses the process, and a breeze from the land, of air cooled by the land, is carried offshore by night. The Pacific cell is of such importance that it has been named the Walker circulation after Sir Gilbert Walker , an early-20th-century director of British observatories in India , who sought

470-527: A diel vertical migration but without more evidence on the biomass of their prey within this zone, these conclusions cannot be made only using this circumstantial evidence. The biomass in the mesopelagic zone is still understudied leading to the biomass of fish within this layer to potentially be underestimated. A more accurate measurement on this biomass may serve to benefit the commercial fishing industry providing them with additional fishing grounds within this region. Moreover, further understanding this region in

564-422: A few days in advance, weather forecasters are continually working to extend this limit through meteorological research and refining current methodologies in weather prediction. However, it is theoretically impossible to make useful day-to-day predictions more than about two weeks ahead, imposing an upper limit to potential for improved prediction skill. Weather is one of the fundamental processes that shape

658-401: A given day. Since outdoor activities are severely curtailed by heavy rain , snow and the wind chill , forecasts can be used to plan activities around these events and to plan ahead to survive through them. Tropical weather forecasting is different from that at higher latitudes. The sun shines more directly on the tropics than on higher latitudes (at least on average over a year), which makes

752-538: A means of predicting when the monsoon winds of India would fail. While he was never successful in doing so, his work led him to the discovery of a link between the periodic pressure variations in the Indian Ocean , and those between the eastern and western Pacific, which he termed the " Southern Oscillation ". The movement of air in the Walker circulation affects the loops on either side. Under normal circumstances,

846-458: A result of the Coriolis effect . The air flows at the surface are called the polar easterlies, flowing from northeast to southwest near the north pole and from southeast to northwest near the south pole. The outflow of air mass from the cell creates harmonic waves in the atmosphere known as Rossby waves . These ultra-long waves determine the path of the polar jet stream , which travels within

940-476: A secondary circulation feature, whose existence depends upon the Hadley and polar cells on either side of it. It might be thought of as an eddy created by the Hadley and polar cells. The air of the Ferrel cell that descends at 30° latitude returns poleward at the ground level, and as it does so it deviates toward the east. In the upper atmosphere of the Ferrel cell, the air moving toward the equator deviates toward

1034-405: A simple system with strong convection drivers. Though cool and dry relative to equatorial air, the air masses at the 60th parallel are still sufficiently warm and moist to undergo convection and drive a thermal loop . At the 60th parallel, the air rises to the tropopause (about 8 km at this latitude) and moves poleward. As it does so, the upper-level air mass deviates toward the east. When

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1128-523: A single jet stream near the 50th parallel north latitude, and Venus has a single jet near the equator. One of the most famous landmarks in the Solar System , Jupiter's Great Red Spot , is an anticyclonic storm known to have existed for at least 300 years. On other giant planets , the lack of a surface allows the wind to reach enormous speeds: gusts of up to 600 metres per second (about 2,100 km/h or 1,300 mph) have been measured on

1222-603: A surface wind to push it into the area of the east Pacific. This and the corresponding effects of the Southern Oscillation result in long-term unseasonable temperatures and precipitation patterns in North and South America, Australia, and Southeast Africa, and the disruption of ocean currents. Meanwhile, in the Atlantic, fast-blowing upper level Westerlies of the Hadley cell form, which would ordinarily be blocked by

1316-401: A wind pattern which pushes Pacific water westward and piles it up in the western Pacific. (Water levels in the western Pacific are about 60 cm higher than in the eastern Pacific.). The daily (diurnal) longitudinal effects are at the mesoscale (a horizontal range of 5 to several hundred kilometres). During the day, air warmed by the relatively hotter land rises, and as it does so it draws

1410-405: Is a result of the highest solar radiation per unit area (solar intensity) falling on the tropics. The solar intensity decreases as the latitude increases, reaching essentially zero at the poles. Longitudinal circulation, however, is a result of the heat capacity of water, its absorptivity, and its mixing. Water absorbs more heat than does the land, but its temperature does not rise as greatly as does

1504-426: Is due to contact with the Earth's surface while radiative losses to space are mostly constant. Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location. Earth's weather system is a chaotic system ; as a result, small changes to one part of the system can grow to have large effects on the system as a whole. Human attempts to control

1598-466: Is in December to March, the movement of the thermal equator to higher southern latitudes takes place then. The Hadley system provides an example of a thermally direct circulation. The power of the Hadley system, considered as a heat engine, is estimated at 200 tera watts . Part of the air rising at 60° latitude diverges at high altitude toward the poles and creates the polar cell. The rest moves toward

1692-412: Is not a property of the fluid, but a violent swirling motion caused by the position and direction of turbulent flow. In 1883, scientist Osborne Reynolds conducted a fluid dynamics experiment involving water and dye, where he adjusted the velocities of the fluids and observed the transition from laminar to turbulent flow, characterized by the formation of eddies and vortices. Turbulent flow is defined as

1786-474: Is the velocity of the fluid, ρ is its density , r is the radius of the tube, and μ is the dynamic viscosity of the fluid. A turbulent flow in a fluid is defined by the critical Reynolds number, for a closed pipe this works out to approximately In terms of the critical Reynolds number, the critical velocity is represented as These are turbulence models in which the Reynolds stresses, as obtained from

1880-643: Is the saving of Japan from invasion by the Mongol fleet of Kublai Khan by the Kamikaze winds in 1281. French claims to Florida came to an end in 1565 when a hurricane destroyed the French fleet, allowing Spain to conquer Fort Caroline . More recently, Hurricane Katrina redistributed over one million people from the central Gulf coast elsewhere across the United States, becoming the largest diaspora in

1974-587: Is the study of short-lived atmospheric phenomena smaller than mesoscale , about 1 km or less. These two branches of meteorology are sometimes grouped together as "mesoscale and microscale meteorology" (MMM) and together study all phenomena smaller than synoptic scale ; that is they study features generally too small to be depicted on a weather map . These include small and generally fleeting cloud "puffs" and other small cloud features. On Earth, temperatures usually range ±40 °C (100 °F to −40 °F) annually. The range of climates and latitudes across

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2068-478: Is the term for the averaging of atmospheric conditions over longer periods of time. When used without qualification, "weather" is generally understood to mean the weather of Earth. Weather is driven by air pressure , temperature , and moisture differences between one place and another. These differences can occur due to the Sun's angle at any particular spot, which varies with latitude . The strong temperature contrast between polar and tropical air gives rise to

2162-421: Is thought to have easterly winds moving at more than 9,600 kilometres per hour (6,000 mph). Weather is not limited to planetary bodies. Like all stars, the Sun's corona is constantly being lost to space, creating what is essentially a very thin atmosphere throughout the Solar System . The movement of mass ejected from the Sun is known as the solar wind . Inconsistencies in this wind and larger events on

2256-413: Is vital in grasping an understanding of environmental systems. By understanding the transport of both particulate and dissolved solids in environmental flows, scientists and engineers will be able to efficiently formulate remediation strategies for pollution events. Eddy formations play a vital role in the fate and transport of solutes and particles in environmental flows such as in rivers, lakes, oceans, and

2350-410: The 70th parallel north . While the Hadley, Ferrel, and polar cells (whose axes are oriented along parallels or latitudes) are the major features of global heat transport, they do not act alone. Temperature differences also drive a set of circulation cells, whose axes of circulation are longitudinally oriented. This atmospheric motion is known as zonal overturning circulation . Latitudinal circulation

2444-415: The Hadley cell while a smaller scale example would be coastal breezes . The atmosphere is a chaotic system . As a result, small changes to one part of the system can accumulate and magnify to cause large effects on the system as a whole. This atmospheric instability makes weather forecasting less predictable than tidal waves or eclipses. Although it is difficult to accurately predict weather more than

2538-553: The Kuroshio Current , and the Antarctic Circumpolar Current, amongst others. Mesoscale ocean eddies are characterized by currents that flow in a roughly circular motion around the center of the eddy. The sense of rotation of these currents may either be cyclonic or anticyclonic (such as Haida Eddies ). Oceanic eddies are also usually made of water masses that are different from those outside

2632-696: The Virgin Islands . As of 2019, tornadoes have had the greatest impact on humans with 42 fatalities while costing crop and property damage over 3 billion dollars. The weather has played a large and sometimes direct part in human history . Aside from climatic changes that have caused the gradual drift of populations (for example the desertification of the Middle East, and the formation of land bridges during glacial periods), extreme weather events have caused smaller scale population movements and intruded directly in historical events. One such event

2726-648: The adiabatic lapse rate . In some situations, the temperature actually increases with height. This phenomenon is known as an inversion and can cause mountaintops to be warmer than the valleys below. Inversions can lead to the formation of fog and often act as a cap that suppresses thunderstorm development. On local scales, temperature differences can occur because different surfaces (such as oceans, forests, ice sheets, or human-made objects) have differing physical characteristics such as reflectivity , roughness, or moisture content. Surface temperature differences in turn cause pressure differences. A hot surface warms

2820-711: The jet stream flow (see baroclinity ). Weather systems in the tropics, such as monsoons or organized thunderstorm systems, are caused by different processes. Because the Earth's axis is tilted relative to its orbital plane, sunlight is incident at different angles at different times of the year. In June the Northern Hemisphere is tilted towards the Sun , so at any given Northern Hemisphere latitude sunlight falls more directly on that spot than in December (see Effect of sun angle on climate ). This effect causes seasons. Over thousands to hundreds of thousands of years, changes in Earth's orbital parameters affect

2914-444: The solar wind with the terrestrial atmosphere can produce spectacular aurorae , and can play havoc with electrically sensitive systems such as electricity grids and radio signals. Eddy (fluid dynamics) In fluid dynamics , an eddy is the swirling of a fluid and the reverse current created when the fluid is in a turbulent flow regime. The moving fluid creates a space devoid of downstream-flowing fluid on

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3008-538: The Atlantic is also thought to be an ocean desert, which creates an interesting paradox due to it hosting a variety of large pelagic fish populations and apex predators . These mesoscale eddies have shown to be beneficial in further creating ecosystem-based management for food web models to better understand the utilization of these eddies by both the apex predators and their prey. Gaube et al. (2018), used “Smart” Position or Temperature Transmitting tags (SPOT) and Pop-Up Satellite Archival Transmitting tags (PSAT) to track

3102-440: The Earth. The process of weathering breaks down the rocks and soils into smaller fragments and then into their constituent substances. During rains precipitation, the water droplets absorb and dissolve carbon dioxide from the surrounding air. This causes the rainwater to be slightly acidic, which aids the erosive properties of water. The released sediment and chemicals are then free to take part in chemical reactions that can affect

3196-450: The Hadley cell are called the trade winds. Though the Hadley cell is described as located at the equator, it shifts northerly (to higher latitudes) in June and July and southerly (toward lower latitudes) in December and January, as a result of the Sun's heating of the surface. The zone where the greatest heating takes place is called the " thermal equator ". As the southern hemisphere's summer

3290-585: The Middle Ages. Finland suffered a severe famine in 1696–1697, during which about one-third of the Finnish population died. Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location. Human beings have attempted to predict the weather informally for millennia, and formally since at least the nineteenth century. Weather forecasts are made by collecting quantitative data about

3384-505: The Walker circulation and unable to reach such intensities. These winds disrupt the tops of nascent hurricanes and greatly diminish the number which are able to reach full strength. El Niño and La Niña are opposite surface temperature anomalies of the Southern Pacific, which heavily influence the weather on a large scale. In the case of El Niño, warm surface water approaches the coasts of South America which results in blocking

3478-468: The Western Pacific are affected. First, the upper-level westerly winds fail. This cuts off the source of returning, cool air that would normally subside at about 30° south latitude, and therefore the air returning as surface easterlies ceases. There are two consequences. Warm water ceases to surge into the eastern Pacific from the west (it was "piled" by past easterly winds) since there is no longer

3572-422: The adjacent zones of Hadley or Ferrel cells, and which typically have light winds, sunny skies, and little precipitation. The atmospheric circulation pattern that George Hadley described was an attempt to explain the trade winds . The Hadley cell is a closed circulation loop which begins at the equator. There, moist air is warmed by the Earth's surface, decreases in density and rises. A similar air mass rising on

3666-479: The air above it causing it to expand and lower the density and the resulting surface air pressure . The resulting horizontal pressure gradient moves the air from higher to lower pressure regions, creating a wind, and the Earth's rotation then causes deflection of this airflow due to the Coriolis effect . The simple systems thus formed can then display emergent behaviour to produce more complex systems and thus other weather phenomena. Large scale examples include

3760-436: The air reaches the polar areas, it has cooled by radiation to space and is considerably denser than the underlying air. It descends, creating a cold, dry high-pressure area. At the polar surface level, the mass of air is driven away from the pole toward the 60th parallel, replacing the air that rose there, and the polar circulation cell is complete. As the air at the surface moves toward the equator, it deviates westwards, again as

3854-466: The air. The data from turbulent-flow phenomena has been used to model different transitions in fluid flow regimes, which are used to thoroughly mix fluids and increase reaction rates within industrial processes. Oceanic and atmospheric currents transfer particles, debris, and organisms all across the globe. While the transport of organisms, such as phytoplankton , are essential for the preservation of ecosystems, oil and other pollutants are also mixed in

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3948-527: The amount and distribution of solar energy received by the Earth and influence long-term climate. (See Milankovitch cycles ). The uneven solar heating (the formation of zones of temperature and moisture gradients, or frontogenesis ) can also be due to the weather itself in the form of cloudiness and precipitation. Higher altitudes are typically cooler than lower altitudes, which is the result of higher surface temperature and radiational heating, which produces

4042-437: The anticyclonic eddies were 57% more common and had more dives and deeper dives than the open ocean eddies and Gulf Stream cyclonic eddies. Within these anticyclonic eddies, the isotherm was displaced 50 meters downward allowing for the warmer water to penetrate deeper in the water column. This warmer water displacement may allow for the white sharks to make longer dives without the added energetic cost from thermal regulation in

4136-413: The arterial tree can cause a number of concerning effects, including atherosclerotic lesions, postsurgical neointimal hyperplasia, in-stent restenosis, vein bypass graft failure, transplant vasculopathy, and aortic valve calcification. Lift and drag properties of golf balls are customized by the manipulation of dimples along the surface of the ball, allowing for the golf ball to travel further and faster in

4230-433: The atmosphere. Upwelling in stratified coastal estuaries warrant the formation of dynamic eddies which distribute nutrients out from beneath the boundary layer to form plumes. Shallow waters, such as those along the coast, play a complex role in the transport of nutrients and pollutants due to the proximity of the upper-boundary driven by the wind and the lower-boundary near the bottom of the water body. Eddies are common in

4324-491: The cooler cyclones. Even though these anticyclonic eddies resulted in lower levels of chlorophyll in comparison to the cyclonic eddies, the warmer waters at deeper depths may allow for a deeper mixed layer and higher concentration of diatoms which in turn result in higher rates of primary productivity. Furthermore, the prey populations could be distributed more within these eddies attracting these larger female sharks to forage in this mesopelagic zone. This diving pattern may follow

4418-580: The current flow and can carry pollution far from its origin. Eddy formations circulate trash and other pollutants into concentrated areas which researchers are tracking to improve clean-up and pollution prevention. The distribution and motion of plastics caused by eddy formations in natural water bodies can be predicted using Lagrangian transport models. Mesoscale ocean eddies play crucial roles in transferring heat poleward, as well as maintaining heat gradients at different depths. Modeling eddy development, as it relates to turbulence and fate transport phenomena,

4512-432: The current state of the atmosphere and using scientific understanding of atmospheric processes to project how the atmosphere will evolve. Once an all-human endeavor based mainly upon changes in barometric pressure , current weather conditions, and sky condition, forecast models are now used to determine future conditions. On the other hand, human input is still required to pick the best possible forecast model to base

4606-686: The difference in current time and the time for which the forecast is being made (the range of the forecast) increases. The use of ensembles and model consensus helps to narrow the error and pick the most likely outcome. There are a variety of end users to weather forecasts. Weather warnings are important forecasts because they are used to protect life and property. Forecasts based on temperature and precipitation are important to agriculture, and therefore to commodity traders within stock markets. Temperature forecasts are used by utility companies to estimate demand over coming days. In some areas, people use weather forecasts to determine what to wear on

4700-412: The downstream side of the object. Fluid behind the obstacle flows into the void creating a swirl of fluid on each edge of the obstacle, followed by a short reverse flow of fluid behind the obstacle flowing upstream, toward the back of the obstacle. This phenomenon is naturally observed behind large emergent rocks in swift-flowing rivers. An eddy is a movement of fluid that deviates from the general flow of

4794-584: The eddy. That is, the water within an eddy usually has different temperature and salinity characteristics to the water outside the eddy. There is a direct link between the water mass properties of an eddy and its rotation. Warm eddies rotate anti-cyclonically, while cold eddies rotate cyclonically. Because eddies may have a vigorous circulation associated with them, they are of concern to naval and commercial operations at sea. Further, because eddies transport anomalously warm or cold water as they move, they have an important influence on heat transport in certain parts of

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4888-405: The effect it has on humans in different situations, etc. Therefore, weather is something people often communicate about. The National Weather Service has an annual report for fatalities, injury, and total damage costs which include crop and property. They gather this data via National Weather Service offices located throughout the 50 states in the United States as well as Puerto Rico , Guam , and

4982-405: The equator where it collides at 30° latitude with the high-level air of the Hadley cell. There it subsides and strengthens the high pressure ridges beneath. A large part of the energy that drives the Ferrel cell is provided by the polar and Hadley cells circulating on either side, which drag the air of the Ferrel cell with it. The Ferrel cell, theorized by William Ferrel (1817–1891), is, therefore,

5076-459: The equator, or a high pressure zone at 30° latitude that moves poleward, will accelerate the Westerlies of the Ferrel cell. A strong high, moving polewards may bring westerly winds for days. The Ferrel system acts as a heat pump with a coefficient of performance of 12.1, consuming kinetic energy from the Hadley and polar systems at an approximate rate of 275 terawatts. The polar cell is

5170-405: The flow in which the system's inertial forces are dominant over the viscous forces. This phenomenon is described by Reynolds number , a unit-less number used to determine when turbulent flow will occur. Conceptually, the Reynolds number is the ratio between inertial forces and viscous forces. The general form for the Reynolds number flowing through a tube of radius r (or diameter d ): where v

5264-479: The fluid. An example for an eddy is a vortex which produces such deviation. However, there are other types of eddies that are not simple vortices. For example, a Rossby wave is an eddy which is an undulation that is a deviation from mean flow, but does not have the local closed streamlines of a vortex. The propensity of a fluid to swirl is used to promote good fuel/air mixing in internal combustion engines. In fluid mechanics and transport phenomena , an eddy

5358-464: The forecast upon, which involves many disciplines such as pattern recognition skills, teleconnections , knowledge of model performance, and knowledge of model biases. The chaotic nature of the atmosphere, the massive computational power required to solve the equations that describe the atmosphere, the error involved in measuring the initial conditions, and an incomplete understanding of atmospheric processes mean that forecasts become less accurate as of

5452-446: The form of massive terrain features or high pressure zones. The weaker Westerlies of the Ferrel cell, however, can be disrupted. The local passage of a cold front may change that in a matter of minutes, and frequently does. As a result, at the surface, winds can vary abruptly in direction. But the winds above the surface, where they are less disrupted by terrain, are essentially westerly. A low pressure zone at 60° latitude that moves toward

5546-858: The greatest snowfall in a period of twelve months occurred in Mount Rainier , Washington, US. It was recorded as 31,102 mm (102.04 ft) of snow. Studying how the weather works on other planets has been seen as helpful in understanding how it works on Earth. Weather on other planets follows many of the same physical principles as weather on Earth , but occurs on different scales and in atmospheres having different chemical composition. The Cassini–Huygens mission to Titan discovered clouds formed from methane or ethane which deposit rain composed of liquid methane and other organic compounds . Earth's atmosphere includes six latitudinal circulation zones, three in each hemisphere. In contrast, Jupiter's banded appearance shows many such zones, Titan has

5640-675: The history of the United States. The Little Ice Age caused crop failures and famines in Europe. During the period known as the Grindelwald Fluctuation (1560–1630), volcanic forcing events seem to have led to more extreme weather events. These included droughts, storms and unseasonal blizzards, as well as causing the Swiss Grindelwald Glacier to expand. The 1690s saw the worst famine in France since

5734-423: The land. As a result, temperature variations on land are greater than on water. The Hadley, Ferrel, and polar cells operate at the largest scale of thousands of kilometers ( synoptic scale ). The latitudinal circulation can also act on this scale of oceans and continents, and this effect is seasonal or even decadal . Warm air rises over the equatorial, continental, and western Pacific Ocean regions. When it reaches

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5828-461: The largest scale atmospheric circulations : the Hadley cell , the Ferrel cell , the polar cell , and the jet stream . Weather systems in the middle latitudes , such as extratropical cyclones , are caused by instabilities of the jet streamflow. Because Earth's axis is tilted relative to its orbital plane (called the ecliptic ), sunlight is incident at different angles at different times of

5922-405: The loop of the Hadley cell. The poleward movement of the air in the upper part of the troposphere deviates toward the east, caused by the coriolis acceleration . At the ground level, however, the movement of the air toward the equator in the lower troposphere deviates toward the west, producing a wind from the east. The winds that flow to the west (from the east, easterly wind) at the ground level in

6016-490: The mid-latitudes are sometimes known as the "zone of mixing." The Hadley and polar cells are truly closed loops, the Ferrel cell is not, and the telling point is in the Westerlies, which are more formally known as "the Prevailing Westerlies." The easterly Trade Winds and the polar easterlies have nothing over which to prevail, as their parent circulation cells are strong enough and face few obstacles either in

6110-478: The more nutrient-filled eastern Pacific waters. Weather Weather is the state of the atmosphere , describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloudy . On Earth , most weather phenomena occur in the lowest layer of the planet's atmosphere , the troposphere , just below the stratosphere . Weather refers to day-to-day temperature, precipitation , and other atmospheric conditions, whereas climate

6204-465: The movement and diving behavior of two female white sharks (Carcharodon carcharias) within the eddies. The eddies were defined using sea surface height (SSH) and contours using the horizontal speed-based radius scale. This study found that the white sharks dove in both cyclones but favored the anticyclone which had three times more dives as the cyclonic eddies. Additionally, in the Gulf Stream eddies,

6298-410: The northern and southern hemispheres. The vast bulk of the atmospheric motion occurs in the Hadley cell. The high pressure systems acting on the Earth's surface are balanced by the low pressure systems elsewhere. As a result, there is a balance of forces acting on the Earth's surface. The horse latitudes are an area of high pressure at about 30° to 35° latitude (north or south) where winds diverge into

6392-616: The ocean contains a sea surface height gradient this creates a jet or current, such as the Antarctic Circumpolar Current . This current as part of a baroclinically unstable system meanders and creates eddies (in much the same way as a meandering river forms an oxbow lake ). These types of mesoscale eddies have been observed in many major ocean currents, including the Gulf Stream , the Agulhas Current ,

6486-549: The ocean, and range in diameter from centimeters to hundreds of kilometers. The smallest scale eddies may last for a matter of seconds, while the larger features may persist for months to years. Eddies that are between about 10 and 500 km (6 and 300 miles) in diameter and persist for periods of days to months are known in oceanography as mesoscale eddies. Mesoscale eddies can be split into two categories: static eddies, caused by flow around an obstacle (see animation) , and transient eddies, caused by baroclinic instability. When

6580-448: The ocean. The sub-tropical Northern Atlantic is known to have both cyclonic and anticyclonic eddies that are associated with high surface chlorophyll and low surface chlorophyll, respectively. The presence of chlorophyll and higher levels of chlorophyll allows this region to support higher biomass of phytoplankton, as well as, supported by areas of increased vertical nutrient fluxes and transportation of biological communities. This area of

6674-399: The other side of the equator forces those rising air masses to move poleward. The rising air creates a low pressure zone near the equator. As the air moves poleward, it cools, becomes denser, and descends at about the 30th parallel , creating a high-pressure area . The descended air then travels toward the equator along the surface, replacing the air that rose from the equatorial zone, closing

6768-417: The planet Neptune . This has created a puzzle for planetary scientists . The weather is ultimately created by solar energy and the amount of energy received by Neptune is only about 1 ⁄ 900 of that received by Earth, yet the intensity of weather phenomena on Neptune is far greater than on Earth. As of 2007 , the strongest planetary winds discovered are on the extrasolar planet HD 189733 b , which

6862-502: The planet can offer extremes of temperature outside this range. The coldest air temperature ever recorded on Earth is −89.2 °C (−128.6 °F), at Vostok Station , Antarctica on 21 July 1983. The hottest air temperature ever recorded was 57.7 °C (135.9 °F) at 'Aziziya , Libya, on 13 September 1922, but that reading is queried . The highest recorded average annual temperature was 34.4 °C (93.9 °F) at Dallol , Ethiopia. The coldest recorded average annual temperature

6956-402: The polar cell are similar in that they are thermally direct; in other words, they exist as a direct consequence of surface temperatures. Their thermal characteristics drive the weather in their domain. The sheer volume of energy that the Hadley cell transports, and the depth of the heat sink contained within the polar cell, ensures that transient weather phenomena not only have negligible effect on

7050-537: The southwest and Beijing's Fangshan District recording a rainfall of 25 millimeters. Whereas there is inconclusive evidence for these techniques' efficacy, there is extensive evidence that human activity such as agriculture and industry results in inadvertent weather modification: The effects of inadvertent weather modification may pose serious threats to many aspects of civilization, including ecosystems , natural resources , food and fiber production, economic development , and human health. Microscale meteorology

7144-536: The surface further (such as acid rain ), and sodium and chloride ions ( salt ) deposited in the seas/oceans. The sediment may reform in time and by geological forces into other rocks and soils. In this way, weather plays a major role in erosion of the surface. Weather, seen from an anthropological perspective, is something all humans in the world constantly experience through their senses, at least while being outside. There are socially and scientifically constructed understandings of what weather is, what makes it change,

7238-400: The surface of the star, such as coronal mass ejections , form a system that has features analogous to conventional weather systems (such as pressure and wind) and is generally known as space weather . Coronal mass ejections have been tracked as far out in the Solar System as Saturn . The activity of this system can affect planetary atmospheres and occasionally surfaces. The interaction of

7332-404: The systems as a whole, but — except under unusual circumstances — they do not form. The endless chain of passing highs and lows which is part of everyday life for mid-latitude dwellers, under the Ferrel cell at latitudes between 30 and 60° latitude, is unknown above the 60th and below the 30th parallels. There are some notable exceptions to this rule; over Europe, unstable weather extends to at least

7426-493: The transitional zone between the tropopause and the Ferrel cell . By acting as a heat sink, the polar cell moves the abundant heat from the equator toward the polar regions. The polar cell, terrain, and katabatic winds in Antarctica can create very cold conditions at the surface, for instance the lowest temperature recorded on Earth : −89.2 °C at Vostok Station in Antarctica, measured in 1983. The Hadley cell and

7520-411: The tropics can occur more spontaneously compared to those at higher latitudes, where they are more tightly controlled by larger-scale forces in the atmosphere. Because of these differences, clouds and rain are more difficult to forecast in the tropics than at higher latitudes. On the other hand, the temperature is easily forecast in the tropics, because it does not change much. The aspiration to control

7614-429: The tropics to the latitudes nearer the poles, and thence to space. The large-scale atmospheric circulation "cells" shift polewards in warmer periods (for example, interglacials compared to glacials ), but remain largely constant as they are, fundamentally, a property of the Earth's size, rotation rate, heating and atmospheric depth, all of which change little. Over very long time periods (hundreds of millions of years),

7708-419: The tropics warm (Stevens 2011). And, the vertical direction (up, as one stands on the Earth's surface) is perpendicular to the Earth's axis of rotation at the equator, while the axis of rotation and the vertical are the same at the pole; this causes the Earth's rotation to influence the atmospheric circulation more strongly at high latitudes than low latitudes. Because of these two factors, clouds and rainstorms in

7802-453: The tropics. In other words, the farther from the tropics one lies, the lower the sun angle is, which causes those locations to be cooler due to the spread of the sunlight over a greater surface. The strong temperature contrast between polar and tropical air gives rise to the large scale atmospheric circulation cells and the jet stream . Weather systems in the mid-latitudes, such as extratropical cyclones , are caused by instabilities of

7896-551: The tropopause, it cools and subsides in a region of relatively cooler water mass. The Pacific Ocean cell plays a particularly important role in Earth's weather. This entirely ocean-based cell comes about as the result of a marked difference in the surface temperatures of the western and eastern Pacific. Under ordinary circumstances, the western Pacific waters are warm, and the eastern waters are cool. The process begins when strong convective activity over equatorial East Asia and subsiding cool air off South America 's west coast create

7990-411: The troposphere (the lower part of the atmosphere). Weather does occur in the stratosphere and can affect weather lower down in the troposphere, but the exact mechanisms are poorly understood. Weather occurs primarily due to air pressure, temperature and moisture differences from one place to another. These differences can occur due to the sun angle at any particular spot, which varies by latitude in

8084-722: The upwelling of nutrient-rich deep water. This has serious impacts on the fish populations. In the La Niña case, the convective cell over the western Pacific strengthens inordinately, resulting in colder than normal winters in North America and a more robust cyclone season in South-East Asia and Eastern Australia . There is also an increased upwelling of deep cold ocean waters and more intense uprising of surface air near South America, resulting in increasing numbers of drought occurrences, although fishermen reap benefits from

8178-420: The weather have occurred throughout history, and there is evidence that human activities such as agriculture and industry have modified weather patterns. Studying how the weather works on other planets has been helpful in understanding how weather works on Earth. A famous landmark in the Solar System , Jupiter's Great Red Spot , is an anticyclonic storm known to have existed for at least 300 years. However,

8272-603: The weather is evident throughout human history: from ancient rituals intended to bring rain for crops to the U.S. Military Operation Popeye , an attempt to disrupt supply lines by lengthening the North Vietnamese monsoon . The most successful attempts at influencing weather involve cloud seeding ; they include the fog - and low stratus dispersion techniques employed by major airports, techniques used to increase winter precipitation over mountains, and techniques to suppress hail . A recent example of weather control

8366-486: The weather behaves as expected. But every few years, the winters become unusually warm or unusually cold, or the frequency of hurricanes increases or decreases, and the pattern sets in for an indeterminate period. The Walker Cell plays a key role in this and in the El Niño phenomenon. If convective activity slows in the Western Pacific for some reason (this reason is not currently known), the climates of areas adjacent to

8460-575: The weather is not limited to planetary bodies. A star's corona is constantly being lost to space, creating what is essentially a very thin atmosphere throughout the Solar System. The movement of mass ejected from the Sun is known as the solar wind . On Earth , common weather phenomena include wind, cloud , rain, snow, fog and dust storms . Less common events include natural disasters such as tornadoes , hurricanes , typhoons and ice storms . Almost all familiar weather phenomena occur in

8554-484: The west. Both of those deviations, as in the case of the Hadley and polar cells, are driven by conservation of angular momentum. As a result, just as the easterly Trade Winds are found below the Hadley cell, the Westerlies are found beneath the Ferrel cell. The Ferrel cell is weak, because it has neither a strong source of heat nor a strong sink, so the airflow and temperatures within it are variable. For this reason,

8648-447: The year. On Earth's surface, temperatures usually range ±40 °C (−40 °F to 104 °F) annually. Over thousands of years, changes in Earth's orbit can affect the amount and distribution of solar energy received by Earth, thus influencing long-term climate and global climate change . Surface temperature differences in turn cause pressure differences. Higher altitudes are cooler than lower altitudes, as most atmospheric heating

8742-561: Was China's preparation for the 2008 Summer Olympic Games . China shot 1,104 rain dispersal rockets from 21 sites in the city of Beijing in an effort to keep rain away from the opening ceremony of the games on 8 August 2008. Guo Hu, head of the Beijing Municipal Meteorological Bureau (BMB), confirmed the success of the operation with 100 millimeters falling in Baoding City of Hebei Province , to

8836-461: Was −55.1 °C (−67.2 °F) at Vostok Station , Antarctica. The coldest average annual temperature in a permanently inhabited location is at Eureka, Nunavut , in Canada, where the annual average temperature is −19.7 °C (−3.5 °F). The windiest place ever recorded is in Antarctica, Commonwealth Bay (George V Coast). Here the gales reach 199 mph (320  km/h ). Furthermore,

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