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131-446: An afterglow in meteorology consists of several atmospheric optical phenomena , with a general definition as a broad arch of whitish or pinkish sunlight in the twilight sky , consisting of the bright segment and the purple light . Purple light mainly occurs when the Sun is 2–6° below the horizon , from civil to nautical twilight , while the bright segment lasts until the end of

262-645: A GPS clock for data logging . Upper air data are of crucial importance for weather forecasting. The most widely used technique is launches of radiosondes . Supplementing the radiosondes a network of aircraft collection is organized by the World Meteorological Organization . Remote sensing , as used in meteorology, is the concept of collecting data from remote weather events and subsequently producing weather information. The common types of remote sensing are Radar , Lidar , and satellites (or photogrammetry ). Each collects data about

393-616: A Problem in Mechanics and Physics that it should be possible to forecast weather from calculations based upon natural laws . It was not until later in the 20th century that advances in the understanding of atmospheric physics led to the foundation of modern numerical weather prediction . In 1922, Lewis Fry Richardson published "Weather Prediction By Numerical Process," after finding notes and derivations he worked on as an ambulance driver in World War I. He described how small terms in

524-498: A Roman geographer, formalized the climatic zone system. In 63–64 AD, Seneca wrote Naturales quaestiones . It was a compilation and synthesis of ancient Greek theories. However, theology was of foremost importance to Seneca, and he believed that phenomena such as lightning were tied to fate. The second book(chapter) of Pliny 's Natural History covers meteorology. He states that more than twenty ancient Greek authors studied meteorology. He did not make any personal contributions, and

655-424: A certain amount of time, if the cloud continues to generate and store more static electricity , the barrier that was created by the atmospheric water vapor will ultimately break down from the stored electrical potential energy. This energy will be released to a local oppositely charged region, in the form of lightning. The strength of each discharge is directly related to the atmospheric permittivity, capacitance, and

786-528: A crystalline structure or alter an existing one, sometimes resulting in characteristic color changes that can be used for measurement . Measuring the quantity of water vapor in a medium can be done directly or remotely with varying degrees of accuracy. Remote methods such electromagnetic absorption are possible from satellites above planetary atmospheres. Direct methods may use electronic transducers, moistened thermometers or hygroscopic materials measuring changes in physical properties or dimensions. Water vapor

917-502: A disproportionate impact, which is why jet traffic has a disproportionately high warming effect. Oxidation of methane is also a major source of water vapour in the stratosphere, and adds about 15% to methane's global warming effect. In the absence of other greenhouse gases, Earth's water vapor would condense to the surface; this has likely happened , possibly more than once. Scientists thus distinguish between non-condensable (driving) and condensable (driven) greenhouse gases, i.e.,

1048-466: A farmer's potential harvest. In 1450, Leone Battista Alberti developed a swinging-plate anemometer , and was known as the first anemometer . In 1607, Galileo Galilei constructed a thermoscope . In 1611, Johannes Kepler wrote the first scientific treatise on snow crystals: "Strena Seu de Nive Sexangula (A New Year's Gift of Hexagonal Snow)." In 1643, Evangelista Torricelli invented the mercury barometer . In 1662, Sir Christopher Wren invented

1179-485: A gale was expected. FitzRoy coined the term "weather forecast" and tried to separate scientific approaches from prophetic ones. Over the next 50 years, many countries established national meteorological services. The India Meteorological Department (1875) was established to follow tropical cyclone and monsoon . The Finnish Meteorological Central Office (1881) was formed from part of Magnetic Observatory of Helsinki University . Japan's Tokyo Meteorological Observatory,

1310-478: A great height by the volcano's explosion, and then globally diffused by the high atmospheric winds. Edvard Munch 's painting The Scream possibly depicts an afterglow during this period. Meteorology Meteorology is a branch of the atmospheric sciences (which include atmospheric chemistry and physics) with a major focus on weather forecasting . The study of meteorology dates back millennia , though significant progress in meteorology did not begin until

1441-480: A great many modelling equations) that significant breakthroughs in weather forecasting were achieved. An important branch of weather forecasting is marine weather forecasting as it relates to maritime and coastal safety, in which weather effects also include atmospheric interactions with large bodies of water. Meteorological phenomena are observable weather events that are explained by the science of meteorology. Meteorological phenomena are described and quantified by

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1572-630: A group of meteorologists in Norway led by Vilhelm Bjerknes developed the Norwegian cyclone model that explains the generation, intensification and ultimate decay (the life cycle) of mid-latitude cyclones , and introduced the idea of fronts , that is, sharply defined boundaries between air masses . The group included Carl-Gustaf Rossby (who was the first to explain the large scale atmospheric flow in terms of fluid dynamics ), Tor Bergeron (who first determined how rain forms) and Jacob Bjerknes . In

1703-488: A key role in lightning production in the atmosphere. From cloud physics , usually clouds are the real generators of static charge as found in Earth's atmosphere. The ability of clouds to hold massive amounts of electrical energy is directly related to the amount of water vapor present in the local system. The amount of water vapor directly controls the permittivity of the air. During times of low humidity, static discharge

1834-681: A layer of liquid water about 25 mm deep. The mean annual precipitation for the planet is about 1 metre, a comparison which implies a rapid turnover of water in the air – on average, the residence time of a water molecule in the troposphere is about 9 to 10 days. Global mean water vapour is about 0.25% of the atmosphere by mass and also varies seasonally, in terms of contribution to atmospheric pressure between 2.62 hPa in July and 2.33 hPa in December. IPCC AR6 expresses medium confidence in increase of total water vapour at about 1-2% per decade; it

1965-486: A legitimate branch of physics. In the 18th century, the invention of the thermometer and barometer allowed for more accurate measurements of temperature and pressure, leading to a better understanding of atmospheric processes. This century also saw the birth of the first meteorological society, the Societas Meteorologica Palatina in 1780. In the 19th century, advances in technology such as

2096-469: A major component in energy production and transport systems since the industrial revolution . Water vapor is a relatively common atmospheric constituent, present even in the solar atmosphere as well as every planet in the Solar System and many astronomical objects including natural satellites , comets and even large asteroids . Likewise the detection of extrasolar water vapor would indicate

2227-576: A major constituent of the atmosphere of dwarf planet , Ceres , largest object in the asteroid belt The detection was made by using the far-infrared abilities of the Herschel Space Observatory . The finding is unexpected because comets , not asteroids , are typically considered to "sprout jets and plumes." According to one of the scientists, "The lines are becoming more and more blurred between comets and asteroids." Scientists studying Mars hypothesize that if water moves about

2358-414: A number of other formulae which can be used. Under certain conditions, such as when the boiling temperature of water is reached, a net evaporation will always occur during standard atmospheric conditions regardless of the percent of relative humidity. This immediate process will dispel massive amounts of water vapor into a cooler atmosphere. Exhaled air is almost fully at equilibrium with water vapor at

2489-496: A period up to a year. His system was based on dividing the year by the setting and the rising of the Pleiad, halves into solstices and equinoxes, and the continuity of the weather for those periods. He also divided months into the new moon, fourth day, eighth day and full moon, in likelihood of a change in the weather occurring. The day was divided into sunrise, mid-morning, noon, mid-afternoon and sunset, with corresponding divisions of

2620-418: A similar distribution in other planetary systems. Water vapor can also be indirect evidence supporting the presence of extraterrestrial liquid water in the case of some planetary mass objects. Water vapor, which reacts to temperature changes, is referred to as a 'feedback', because it amplifies the effect of forces that initially cause the warming. So, it is a greenhouse gas. Whenever a water molecule leaves

2751-950: A snapshot of a variety of weather conditions at one single location and are usually at a weather station , a ship or a weather buoy . The measurements taken at a weather station can include any number of atmospheric observables. Usually, temperature, pressure , wind measurements, and humidity are the variables that are measured by a thermometer, barometer, anemometer, and hygrometer, respectively. Professional stations may also include air quality sensors ( carbon monoxide , carbon dioxide , methane , ozone , dust , and smoke ), ceilometer (cloud ceiling), falling precipitation sensor, flood sensor , lightning sensor , microphone ( explosions , sonic booms , thunder ), pyranometer / pyrheliometer / spectroradiometer (IR/Vis/UV photodiodes ), rain gauge / snow gauge , scintillation counter ( background radiation , fallout , radon ), seismometer ( earthquakes and tremors), transmissometer (visibility), and

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2882-399: A surface and diffuses into a surrounding gas, it is said to have evaporated . Each individual water molecule which transitions between a more associated (liquid) and a less associated (vapor/gas) state does so through the absorption or release of kinetic energy . The aggregate measurement of this kinetic energy transfer is defined as thermal energy and occurs only when there is differential in

3013-431: A surface, a net warming occurs on that surface. The water molecule brings heat energy with it. In turn, the temperature of the atmosphere drops slightly. In the atmosphere, condensation produces clouds, fog and precipitation (usually only when facilitated by cloud condensation nuclei ). The dew point of an air parcel is the temperature to which it must cool before water vapor in the air begins to condense. Condensation in

3144-422: A working medium which shuttles forth and back between both. The upper temperature level is given by the soil or water surface of the Earth, which absorbs the incoming sun radiation and warms up, evaporating water. The moist and warm air at the ground is lighter than its surroundings and rises up to the upper limit of the troposphere. There the water molecules radiate their thermal energy into outer space, cooling down

3275-401: Is a by-product of respiration in plants and animals. Its contribution to the pressure, increases as its concentration increases. Its partial pressure contribution to air pressure increases, lowering the partial pressure contribution of the other atmospheric gases (Dalton's Law) . The total air pressure must remain constant. The presence of water vapor in the air naturally dilutes or displaces

3406-607: Is also responsible for twilight in Opticae thesaurus ; he estimated that twilight begins when the sun is 19 degrees below the horizon , and also used a geometric determination based on this to estimate the maximum possible height of the Earth's atmosphere as 52,000 passim (about 49 miles, or 79 km). Adelard of Bath was one of the early translators of the classics. He also discussed meteorological topics in his Quaestiones naturales . He thought dense air produced propulsion in

3537-406: Is an important greenhouse gas owing to the presence of the hydroxyl bond which strongly absorbs in the infra-red . Water vapor is the "working medium" of the atmospheric thermodynamic engine which transforms heat energy from sun irradiation into mechanical energy in the form of winds. Transforming thermal energy into mechanical energy requires an upper and a lower temperature level, as well as

3668-411: Is expected to increase by around 7% per °C of warming. Episodes of surface geothermal activity, such as volcanic eruptions and geysers, release variable amounts of water vapor into the atmosphere. Such eruptions may be large in human terms, and major explosive eruptions may inject exceptionally large masses of water exceptionally high into the atmosphere, but as a percentage of total atmospheric water,

3799-411: Is extremely valuable to certain scientific disciplines, a dramatic example being the collection of meteorites that are left exposed in unparalleled numbers and excellent states of preservation. Sublimation is important in the preparation of certain classes of biological specimens for scanning electron microscopy . Typically the specimens are prepared by cryofixation and freeze-fracture , after which

3930-406: Is lighter or less dense than dry air . At equivalent temperatures it is buoyant with respect to dry air, whereby the density of dry air at standard temperature and pressure (273.15 K, 101.325 kPa) is 1.27 g/L and water vapor at standard temperature has a vapor pressure of 0.6 kPa and the much lower density of 0.0048 g/L. Water vapor and dry air density calculations at 0 °C: At

4061-487: Is not mandatory to be hired by the media. Each science has its own unique sets of laboratory equipment. In the atmosphere, there are many things or qualities of the atmosphere that can be measured. Rain, which can be observed, or seen anywhere and anytime was one of the first atmospheric qualities measured historically. Also, two other accurately measured qualities are wind and humidity. Neither of these can be seen but can be felt. The devices to measure these three sprang up in

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4192-433: Is not merely below its boiling point (100 °C), but at altitude it goes below its freezing point (0 °C), due to water's highly polar attraction . When combined with its quantity, water vapor then has a relevant dew point and frost point , unlike e. g., carbon dioxide and methane. Water vapor thus has a scale height a fraction of that of the bulk atmosphere, as the water condenses and exits , primarily in

4323-406: Is quick and easy. During times of higher humidity, fewer static discharges occur. Permittivity and capacitance work hand in hand to produce the megawatt outputs of lightning. After a cloud, for instance, has started its way to becoming a lightning generator, atmospheric water vapor acts as a substance (or insulator ) that decreases the ability of the cloud to discharge its electrical energy. Over

4454-413: Is that water vapor amounts over land areas decrease more in winter months than adjacent ocean areas do. This is largely because air temperatures over land drop more in the winter than temperatures over the ocean. Water vapor condenses more rapidly in colder air. As water vapor absorbs light in the visible spectral range, its absorption can be used in spectroscopic applications (such as DOAS ) to determine

4585-488: Is used as a lifting gas by a thermal airship the water vapor is heated to form steam so that its vapor pressure is greater than the surrounding air pressure in order to maintain the shape of a theoretical "steam balloon", which yields approximately 60% the lift of helium and twice that of hot air. The amount of water vapor in an atmosphere is constrained by the restrictions of partial pressures and temperature. Dew point temperature and relative humidity act as guidelines for

4716-454: The 22° and 46° halos . The ancient Greeks were the first to make theories about the weather. Many natural philosophers studied the weather. However, as meteorological instruments did not exist, the inquiry was largely qualitative, and could only be judged by more general theoretical speculations. Herodotus states that Thales predicted the solar eclipse of 585 BC. He studied Babylonian equinox tables. According to Seneca, he gave

4847-413: The Earth's magnetic field lines. In 1494, Christopher Columbus experienced a tropical cyclone, which led to the first written European account of a hurricane. In 1686, Edmund Halley presented a systematic study of the trade winds and monsoons and identified solar heating as the cause of atmospheric motions. In 1735, an ideal explanation of global circulation through study of the trade winds

4978-644: The Kitab al-Nabat (Book of Plants), in which he deals with the application of meteorology to agriculture during the Arab Agricultural Revolution . He describes the meteorological character of the sky, the planets and constellations , the sun and moon , the lunar phases indicating seasons and rain, the anwa ( heavenly bodies of rain), and atmospheric phenomena such as winds, thunder, lightning, snow, floods, valleys, rivers, lakes. In 1021, Alhazen showed that atmospheric refraction

5109-628: The Smithsonian Institution began to establish an observation network across the United States under the leadership of Joseph Henry . Similar observation networks were established in Europe at this time. The Reverend William Clement Ley was key in understanding of cirrus clouds and early understandings of Jet Streams . Charles Kenneth Mackinnon Douglas , known as 'CKM' Douglas read Ley's papers after his death and carried on

5240-491: The atmosphere . The percentage of water vapor in surface air varies from 0.01% at -42 °C (-44 °F) to 4.24% when the dew point is 30 °C (86 °F). Over 99% of atmospheric water is in the form of vapour, rather than liquid water or ice, and approximately 99.13% of the water vapour is contained in the troposphere . The condensation of water vapor to the liquid or ice phase is responsible for clouds , rain, snow, and other precipitation , all of which count among

5371-417: The heat capacity of gases varies inversely with atomic weight . In 1824, Sadi Carnot analyzed the efficiency of steam engines using caloric theory; he developed the notion of a reversible process and, in postulating that no such thing exists in nature, laid the foundation for the second law of thermodynamics . In 1716, Edmund Halley suggested that aurorae are caused by "magnetic effluvia" moving along

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5502-637: The phlogiston theory . In 1777, Antoine Lavoisier discovered oxygen and developed an explanation for combustion. In 1783, in Lavoisier's essay "Reflexions sur le phlogistique," he deprecates the phlogiston theory and proposes a caloric theory . In 1804, John Leslie observed that a matte black surface radiates heat more effectively than a polished surface, suggesting the importance of black-body radiation . In 1808, John Dalton defended caloric theory in A New System of Chemistry and described how it combines with matter, especially gases; he proposed that

5633-509: The troposphere , the lowest layer of the atmosphere. Carbon dioxide ( CO 2 ) and methane , being well-mixed in the atmosphere, tend to rise above water vapour. The absorption and emission of both compounds contribute to Earth's emission to space, and thus the planetary greenhouse effect . This greenhouse forcing is directly observable, via distinct spectral features versus water vapor, and observed to be rising with rising CO 2 levels. Conversely, adding water vapor at high altitudes has

5764-404: The 18th century. The 19th century saw modest progress in the field after weather observation networks were formed across broad regions. Prior attempts at prediction of weather depended on historical data. It was not until after the elucidation of the laws of physics, and more particularly in the latter half of the 20th century, the development of the computer (allowing for the automated solution of

5895-528: The Aristotelian method. The work of Theophrastus remained a dominant influence in weather forecasting for nearly 2,000 years. Meteorology continued to be studied and developed over the centuries, but it was not until the Renaissance in the 14th to 17th centuries that significant advancements were made in the field. Scientists such as Galileo and Descartes introduced new methods and ideas, leading to

6026-520: The Great was the first to propose that each drop of falling rain had the form of a small sphere, and that this form meant that the rainbow was produced by light interacting with each raindrop. Roger Bacon was the first to calculate the angular size of the rainbow. He stated that a rainbow summit cannot appear higher than 42 degrees above the horizon. In the late 13th century and early 14th century, Kamāl al-Dīn al-Fārisī and Theodoric of Freiberg were

6157-541: The Modification of Clouds , in which he assigns cloud types Latin names. In 1806, Francis Beaufort introduced his system for classifying wind speeds . Near the end of the 19th century the first cloud atlases were published, including the International Cloud Atlas , which has remained in print ever since. The April 1960 launch of the first successful weather satellite , TIROS-1 , marked

6288-444: The above water vapor feedback. Fog and clouds form through condensation around cloud condensation nuclei . In the absence of nuclei, condensation will only occur at much lower temperatures. Under persistent condensation or deposition, cloud droplets or snowflakes form, which precipitate when they reach a critical mass. Atmospheric concentration of water vapour is highly variable between locations and times, from 10 ppmv in

6419-425: The actual rate of evaporation from a standardized "pan" open water surface outdoors, at various locations nationwide. Others do likewise around the world. The US data is collected and compiled into an annual evaporation map. The measurements range from under 30 to over 120 inches per year. Formulas can be used for calculating the rate of evaporation from a water surface such as a swimming pool. In some countries,

6550-476: The advancement in weather forecasting and satellite technology, meteorology has become an integral part of everyday life, and is used for many purposes such as aviation, agriculture, and disaster management. In 1441, King Sejong 's son, Prince Munjong of Korea, invented the first standardized rain gauge . These were sent throughout the Joseon dynasty of Korea as an official tool to assess land taxes based upon

6681-962: The air". Early attempts at predicting weather were often related to prophecy and divining , and were sometimes based on astrological ideas. Ancient religions believed meteorological phenomena to be under the control of the gods. The ability to predict rains and floods based on annual cycles was evidently used by humans at least from the time of agricultural settlement if not earlier. Early approaches to predicting weather were based on astrology and were practiced by priests. The Egyptians had rain-making rituals as early as 3500 BC. Ancient Indian Upanishads contain mentions of clouds and seasons . The Samaveda mentions sacrifices to be performed when certain phenomena were noticed. Varāhamihira 's classical work Brihatsamhita , written about 500 AD, provides evidence of weather observation. Cuneiform inscriptions on Babylonian tablets included associations between thunder and rain. The Chaldeans differentiated

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6812-581: The amount of water vapor in the atmosphere. This is done operationally, e.g. from the Global Ozone Monitoring Experiment (GOME) spectrometers on ERS (GOME) and MetOp (GOME-2). The weaker water vapor absorption lines in the blue spectral range and further into the UV up to its dissociation limit around 243 nm are mostly based on quantum mechanical calculations and are only partly confirmed by experiments. Water vapor plays

6943-498: The appendix Les Meteores , he applied these principles to meteorology. He discussed terrestrial bodies and vapors which arise from them, proceeding to explain the formation of clouds from drops of water, and winds, clouds then dissolving into rain, hail and snow. He also discussed the effects of light on the rainbow. Descartes hypothesized that all bodies were composed of small particles of different shapes and interwovenness. All of his theories were based on this hypothesis. He explained

7074-494: The atmosphere attenuates radar signals. In addition, atmospheric water will reflect and refract signals to an extent that depends on whether it is vapor, liquid or solid. Generally, radar signals lose strength progressively the farther they travel through the troposphere. Different frequencies attenuate at different rates, such that some components of air are opaque to some frequencies and transparent to others. Radio waves used for broadcasting and other communication experience

7205-412: The atmosphere can be divided into distinct areas that depend on both time and spatial scales. At one extreme of this scale is climatology. In the timescales of hours to days, meteorology separates into micro-, meso-, and synoptic scale meteorology. Respectively, the geospatial size of each of these three scales relates directly with the appropriate timescale. Other subclassifications are used to describe

7336-502: The atmosphere forms cloud droplets. Also, a net condensation of water vapor occurs on surfaces when the temperature of the surface is at or below the dew point temperature of the atmosphere. Deposition is a phase transition separate from condensation which leads to the direct formation of ice from water vapor. Frost and snow are examples of deposition. There are several mechanisms of cooling by which condensation occurs: 1) Direct loss of heat by conduction or radiation. 2) Cooling from

7467-456: The atmosphere from a remote location and, usually, stores the data where the instrument is located. Radar and Lidar are not passive because both use EM radiation to illuminate a specific portion of the atmosphere. Weather satellites along with more general-purpose Earth-observing satellites circling the earth at various altitudes have become an indispensable tool for studying a wide range of phenomena from forest fires to El Niño . The study of

7598-671: The beginning of the age where weather information became available globally. In 1648, Blaise Pascal rediscovered that atmospheric pressure decreases with height, and deduced that there is a vacuum above the atmosphere. In 1738, Daniel Bernoulli published Hydrodynamics , initiating the Kinetic theory of gases and established the basic laws for the theory of gases. In 1761, Joseph Black discovered that ice absorbs heat without changing its temperature when melting. In 1772, Black's student Daniel Rutherford discovered nitrogen , which he called phlogisticated air , and together they developed

7729-460: The best known products of meteorologists for the public, weather presenters on radio and television are not necessarily professional meteorologists. They are most often reporters with little formal meteorological training, using unregulated titles such as weather specialist or weatherman . The American Meteorological Society and National Weather Association issue "Seals of Approval" to weather broadcasters who meet certain requirements but this

7860-460: The body temperature. In the cold air the exhaled vapor quickly condenses, thus showing up as a fog or mist of water droplets and as condensation or frost on surfaces. Forcibly condensing these water droplets from exhaled breath is the basis of exhaled breath condensate , an evolving medical diagnostic test. Controlling water vapor in air is a key concern in the heating, ventilating, and air-conditioning (HVAC) industry. Thermal comfort depends on

7991-455: The broken surface is freeze-etched, being eroded by exposure to vacuum until it shows the required level of detail. This technique can display protein molecules, organelle structures and lipid bilayers with very low degrees of distortion. Water vapor will only condense onto another surface when that surface is cooler than the dew point temperature, or when the water vapor equilibrium in air has been exceeded. When water vapor condenses onto

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8122-401: The calculations led to unrealistic results. Though numerical analysis later found that this was due to numerical instability . Starting in the 1950s, numerical forecasts with computers became feasible. The first weather forecasts derived this way used barotropic (single-vertical-level) models, and could successfully predict the large-scale movement of midlatitude Rossby waves , that is,

8253-444: The chaotic nature of the atmosphere. Mathematical models used to predict the long term weather of the Earth ( climate models ), have been developed that have a resolution today that are as coarse as the older weather prediction models. These climate models are used to investigate long-term climate shifts, such as what effects might be caused by human emission of greenhouse gases . Meteorologists are scientists who study and work in

8384-413: The church and princes. This was supported by scientists like Johannes Muller , Leonard Digges , and Johannes Kepler . However, there were skeptics. In the 14th century, Nicole Oresme believed that weather forecasting was possible, but that the rules for it were unknown at the time. Astrological influence in meteorology persisted until the eighteenth century. Gerolamo Cardano 's De Subilitate (1550)

8515-616: The climate with public health. During the Age of Enlightenment meteorology tried to rationalise traditional weather lore, including astrological meteorology. But there were also attempts to establish a theoretical understanding of weather phenomena. Edmond Halley and George Hadley tried to explain trade winds . They reasoned that the rising mass of heated equator air is replaced by an inflow of cooler air from high latitudes. A flow of warm air at high altitude from equator to poles in turn established an early picture of circulation. Frustration with

8646-422: The clouds and winds extended up to 111 miles, but Posidonius thought that they reached up to five miles, after which the air is clear, liquid and luminous. He closely followed Aristotle's theories. By the end of the second century BC, the center of science shifted from Athens to Alexandria , home to the ancient Library of Alexandria . In the 2nd century AD, Ptolemy 's Almagest dealt with meteorology, because it

8777-454: The coldest air to 5% (50 000 ppmv) in humid tropical air, and can be measured with a combination of land observations, weather balloons and satellites. The water content of the atmosphere as a whole is constantly depleted by precipitation. At the same time it is constantly replenished by evaporation, most prominently from oceans, lakes, rivers, and moist earth. Other sources of atmospheric water include combustion, respiration, volcanic eruptions,

8908-461: The constellation Pegasus, provides the first evidence of atmospheric water vapor beyond the Solar System. A star called CW Leonis was found to have a ring of vast quantities of water vapor circling the aging, massive star . A NASA satellite designed to study chemicals in interstellar gas clouds, made the discovery with an onboard spectrometer. Most likely, "the water vapor was vaporized from

9039-495: The description of what is now known as the hydrologic cycle . His work would remain an authority on meteorology for nearly 2,000 years. The book De Mundo (composed before 250 BC or between 350 and 200 BC) noted: After Aristotle, progress in meteorology stalled for a long time. Theophrastus compiled a book on weather forecasting, called the Book of Signs , as well as On Winds . He gave hundreds of signs for weather phenomena for

9170-416: The drop in air pressure which occurs with uplift of air, also known as adiabatic cooling . Air can be lifted by mountains, which deflect the air upward, by convection, and by cold and warm fronts. 3) Advective cooling - cooling due to horizontal movement of air. A number of chemical reactions have water as a product. If the reactions take place at temperatures higher than the dew point of the surrounding air

9301-651: The early study of weather systems. Nineteenth century researchers in meteorology were drawn from military or medical backgrounds, rather than trained as dedicated scientists. In 1854, the United Kingdom government appointed Robert FitzRoy to the new office of Meteorological Statist to the Board of Trade with the task of gathering weather observations at sea. FitzRoy's office became the United Kingdom Meteorological Office in 1854,

9432-488: The equator as the seasons change. This band of humidity is part of the Intertropical Convergence Zone , where the easterly trade winds from each hemisphere converge and produce near-daily thunderstorms and clouds. Farther from the equator, water vapor concentrations are high in the hemisphere experiencing summer and low in the one experiencing winter. Another pattern that shows up in the time series

9563-443: The equilibrium vapor pressure; 100% relative humidity occurs when the partial pressure of water vapor is equal to the equilibrium vapor pressure. This condition is often referred to as complete saturation. Humidity ranges from 0 grams per cubic metre in dry air to 30 grams per cubic metre (0.03 ounce per cubic foot) when the vapor is saturated at 30 °C. Sublimation is the process by which water molecules directly leave

9694-410: The evaporation rate far exceeds the precipitation rate. Evaporative cooling is restricted by atmospheric conditions . Humidity is the amount of water vapor in the air. The vapor content of air is measured with devices known as hygrometers . The measurements are usually expressed as specific humidity or percent relative humidity . The temperatures of the atmosphere and the water surface determine

9825-487: The existence of a circulation cell in the mid-latitudes, and the air within deflected by the Coriolis force resulting in the prevailing westerly winds. Late in the 19th century, the motion of air masses along isobars was understood to be the result of the large-scale interaction of the pressure gradient force and the deflecting force. By 1912, this deflecting force was named the Coriolis effect. Just after World War I,

9956-471: The explanation that the cause of the Nile 's annual floods was due to northerly winds hindering its descent by the sea. Anaximander and Anaximenes thought that thunder and lightning was caused by air smashing against the cloud, thus kindling the flame. Early meteorological theories generally considered that there was a fire-like substance in the atmosphere. Anaximander defined wind as a flowing of air, but this

10087-443: The field of meteorology. The American Meteorological Society publishes and continually updates an authoritative electronic Meteorology Glossary . Meteorologists work in government agencies , private consulting and research services, industrial enterprises, utilities, radio and television stations , and in education . In the United States, meteorologists held about 10,000 jobs in 2018. Although weather forecasts and warnings are

10218-664: The first weather observing network, that consisted of meteorological stations in Florence , Cutigliano , Vallombrosa , Bologna , Parma , Milan , Innsbruck , Osnabrück , Paris and Warsaw . The collected data were sent to Florence at regular time intervals. In the 1660s Robert Hooke of the Royal Society of London sponsored networks of weather observers. Hippocrates ' treatise Airs, Waters, and Places had linked weather to disease. Thus early meteorologists attempted to correlate weather patterns with epidemic outbreaks, and

10349-400: The first time, a practical method for quickly gathering surface weather observations from a wide area. This data could be used to produce maps of the state of the atmosphere for a region near the Earth's surface and to study how these states evolved through time. To make frequent weather forecasts based on these data required a reliable network of observations, but it was not until 1849 that

10480-407: The first to give the correct explanations for the primary rainbow phenomenon. Theoderic went further and also explained the secondary rainbow. By the middle of the sixteenth century, meteorology had developed along two lines: theoretical science based on Meteorologica , and astrological weather forecasting. The pseudoscientific prediction by natural signs became popular and enjoyed protection of

10611-633: The first weather forecasts and temperature predictions. In the 20th and 21st centuries, with the advent of computer models and big data, meteorology has become increasingly dependent on numerical methods and computer simulations. This has greatly improved weather forecasting and climate predictions. Additionally, meteorology has expanded to include other areas such as air quality, atmospheric chemistry, and climatology. The advancement in observational, theoretical and computational technologies has enabled ever more accurate weather predictions and understanding of weather pattern and air pollution. In current time, with

10742-603: The forerunner of the Japan Meteorological Agency , began constructing surface weather maps in 1883. The United States Weather Bureau (1890) was established under the United States Department of Agriculture . The Australian Bureau of Meteorology (1906) was established by a Meteorology Act to unify existing state meteorological services. In 1904, Norwegian scientist Vilhelm Bjerknes first argued in his paper Weather Forecasting as

10873-527: The form of wind. He explained thunder by saying that it was due to ice colliding in clouds, and in Summer it melted. In the thirteenth century, Aristotelian theories reestablished dominance in meteorology. For the next four centuries, meteorological work by and large was mostly commentary . It has been estimated over 156 commentaries on the Meteorologica were written before 1650. Experimental evidence

11004-435: The golden-red glowing light from the sunset and sunrise reflected in the sky, and in particularly for its last stage, when the purple light is reflected. The opposite of an afterglow is a foreglow , which occurs before sunrise . Sunlight reaches Earth around civil twilight during golden hour intensely in its low-energy and low-frequency red component . During this part of civil twilight after sunset and before sundawn

11135-548: The highest amounts (6 centimeters) appear in dark blue. Areas of missing data appear in shades of gray. The maps are based on data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor on NASA's Aqua satellite. The most noticeable pattern in the time series is the influence of seasonal temperature changes and incoming sunlight on water vapor. In the tropics, a band of extremely humid air wobbles north and south of

11266-514: The interdisciplinary field of hydrometeorology . The interactions between Earth's atmosphere and its oceans are part of a coupled ocean-atmosphere system. Meteorology has application in many diverse fields such as the military, energy production, transport, agriculture, and construction. The word meteorology is from the Ancient Greek μετέωρος metéōros ( meteor ) and -λογία -logia ( -(o)logy ), meaning "the study of things high in

11397-413: The lack of discipline among weather observers, and the poor quality of the instruments, led the early modern nation states to organise large observation networks. Thus, by the end of the 18th century, meteorologists had access to large quantities of reliable weather data. In 1832, an electromagnetic telegraph was created by Baron Schilling . The arrival of the electrical telegraph in 1837 afforded, for

11528-510: The lakes and the Nile. Hippocrates inquired into the effect of weather on health. Eudoxus claimed that bad weather followed four-year periods, according to Pliny. These early observations would form the basis for Aristotle 's Meteorology , written in 350 BC. Aristotle is considered the founder of meteorology. One of the most impressive achievements described in the Meteorology is

11659-437: The late 16th century and first half of the 17th century a range of meteorological instruments were invented – the thermometer , barometer , hydrometer , as well as wind and rain gauges. In the 1650s natural philosophers started using these instruments to systematically record weather observations. Scientific academies established weather diaries and organised observational networks. In 1654, Ferdinando II de Medici established

11790-443: The mechanical, self-emptying, tipping bucket rain gauge. In 1714, Gabriel Fahrenheit created a reliable scale for measuring temperature with a mercury-type thermometer . In 1742, Anders Celsius , a Swedish astronomer, proposed the "centigrade" temperature scale, the predecessor of the current Celsius scale. In 1783, the first hair hygrometer was demonstrated by Horace-Bénédict de Saussure . In 1802–1803, Luke Howard wrote On

11921-448: The mid-15th century and were respectively the rain gauge , the anemometer, and the hygrometer. Many attempts had been made prior to the 15th century to construct adequate equipment to measure the many atmospheric variables. Many were faulty in some way or were simply not reliable. Even Aristotle noted this in some of his work as the difficulty to measure the air. Sets of surface measurements are important data to meteorologists. They give

12052-437: The moist air conditions. Non-human comfort situations are called refrigeration , and also are affected by water vapor. For example, many food stores, like supermarkets, utilize open chiller cabinets, or food cases , which can significantly lower the water vapor pressure (lowering humidity). This practice delivers several benefits as well as problems. Gaseous water represents a small but environmentally significant constituent of

12183-468: The most significant elements of what we experience as weather. Less obviously, the latent heat of vaporization , which is released to the atmosphere whenever condensation occurs, is one of the most important terms in the atmospheric energy budget on both local and global scales. For example, latent heat release in atmospheric convection is directly responsible for powering destructive storms such as tropical cyclones and severe thunderstorms . Water vapor

12314-542: The most used reference formula is the Goff-Gratch equation for the SVP over liquid water below zero degrees Celsius: where T , temperature of the moist air, is given in units of kelvin , and p is given in units of millibars ( hectopascals ). The formula is valid from about −50 to 102 °C; however there are a very limited number of measurements of the vapor pressure of water over supercooled liquid water. There are

12445-453: The nautical twilight. Afterglow is often in cases of volcanic eruptions discussed, while its purple light is discussed as a different particular volcanic purple light . Specifically in volcanic occurrences it is light scattered by fine particulates , like dust , suspended in the atmosphere . In the case of alpenglow , which is similar to the Belt of Venus , afterglow is used in general for

12576-553: The night, with change being likely at one of these divisions. Applying the divisions and a principle of balance in the yearly weather, he came up with forecasts like that if a lot of rain falls in the winter, the spring is usually dry. Rules based on actions of animals are also present in his work, like that if a dog rolls on the ground, it is a sign of a storm. Shooting stars and the Moon were also considered significant. However, he made no attempt to explain these phenomena, referring only to

12707-431: The oceans, clouds and continents of the Earth. Vapor surrounds the planet but is unevenly distributed. The image loop on the right shows monthly average of water vapor content with the units are given in centimeters, which is the precipitable water or equivalent amount of water that could be produced if all the water vapor in the column were to condense. The lowest amounts of water vapor (0 centimeters) appear in yellow, and

12838-511: The opposite effect. Rene Descartes 's Discourse on the Method (1637) typifies the beginning of the scientific revolution in meteorology. His scientific method had four principles: to never accept anything unless one clearly knew it to be true; to divide every difficult problem into small problems to tackle; to proceed from the simple to the complex, always seeking relationships; to be as complete and thorough as possible with no prejudice. In

12969-440: The other air components as its concentration increases. This can have an effect on respiration. In very warm air (35 °C) the proportion of water vapor is large enough to give rise to the stuffiness that can be experienced in humid jungle conditions or in poorly ventilated buildings. Water vapor has lower density than that of air and is therefore buoyant in air but has lower vapor pressure than that of air. When water vapor

13100-526: The pattern of atmospheric lows and highs . In 1959, the UK Meteorological Office received its first computer, a Ferranti Mercury . In the 1960s, the chaotic nature of the atmosphere was first observed and mathematically described by Edward Lorenz , founding the field of chaos theory . These advances have led to the current use of ensemble forecasting in most major forecasting centers, to take into account uncertainty arising from

13231-461: The planet, it does so as vapor. The brilliance of comet tails comes largely from water vapor. On approach to the Sun , the ice many comets carry sublimes to vapor. Knowing a comet's distance from the sun, astronomers may deduce the comet's water content from its brilliance. Water vapor has also been confirmed outside the Solar System. Spectroscopic analysis of HD 209458 b , an extrasolar planet in

13362-486: The process of water vapor in the water cycle . Energy input, such as sunlight, can trigger more evaporation on an ocean surface or more sublimation on a chunk of ice on top of a mountain. The balance between condensation and evaporation gives the quantity called vapor partial pressure . The maximum partial pressure ( saturation pressure ) of water vapor in air varies with temperature of the air and water vapor mixture. A variety of empirical formulas exist for this quantity;

13493-415: The prognostic fluid dynamics equations that govern atmospheric flow could be neglected, and a numerical calculation scheme that could be devised to allow predictions. Richardson envisioned a large auditorium of thousands of people performing the calculations. However, the sheer number of calculations required was too large to complete without electronic computers, and the size of the grid and time steps used in

13624-526: The rain as caused by clouds becoming too large for the air to hold, and that clouds became snow if the air was not warm enough to melt them, or hail if they met colder wind. Like his predecessors, Descartes's method was deductive, as meteorological instruments were not developed and extensively used yet. He introduced the Cartesian coordinate system to meteorology and stressed the importance of mathematics in natural science. His work established meteorology as

13755-403: The red sunlight remains visible by scattering through particles in the air. Backscattering , possibly after being reflected off clouds or high snowfields in mountain regions, furthermore creates a reddish to pinkish light. The high-energy and high-frequency components of light towards blue are scattered out broadly, producing the broader blue light of nautical twilight before or after

13886-423: The reddish light of civil twilight, while in combination with the reddish light producing the purple light. This period of blue dominating is referred to as the blue hour and is, like the golden hour, widely treasured by photographers and painters. After the 1883 eruption of the volcano Krakatoa , a remarkable series of red sunsets appeared worldwide. An enormous amount of exceedingly fine dust were blown to

14017-640: The role of such processes is trivial. The relative concentrations of the various gases emitted by volcanoes varies considerably according to the site and according to the particular event at any one site. However, water vapor is consistently the commonest volcanic gas ; as a rule, it comprises more than 60% of total emissions during a subaerial eruption . Atmospheric water vapor content is expressed using various measures. These include vapor pressure, specific humidity , mixing ratio, dew point temperature, and relative humidity . Because water molecules absorb microwaves and other radio wave frequencies, water in

14148-421: The same effect. Water vapor reflects radar to a lesser extent than do water's other two phases. In the form of drops and ice crystals, water acts as a prism, which it does not do as an individual molecule ; however, the existence of water vapor in the atmosphere causes the atmosphere to act as a giant prism. A comparison of GOES-12 satellite images shows the distribution of atmospheric water vapor relative to

14279-404: The same temperature, a column of dry air will be denser or heavier than a column of air containing any water vapor, the molar mass of diatomic nitrogen and diatomic oxygen both being greater than the molar mass of water. Thus, any volume of dry air will sink if placed in a larger volume of moist air. Also, a volume of moist air will rise or be buoyant if placed in a larger region of dry air. As

14410-442: The scientific revolution in meteorology. Speculation on the cause of the flooding of the Nile ended when Eratosthenes , according to Proclus , stated that it was known that man had gone to the sources of the Nile and observed the rains, although interest in its implications continued. During the era of Roman Greece and Europe, scientific interest in meteorology waned. In the 1st century BC, most natural philosophers claimed that

14541-440: The seasons. He believed that fire and water opposed each other in the atmosphere, and when fire gained the upper hand, the result was summer, and when water did, it was winter. Democritus also wrote about the flooding of the Nile. He said that during the summer solstice, snow in northern parts of the world melted. This would cause vapors to form clouds, which would cause storms when driven to the Nile by northerly winds, thus filling

14672-597: The second oldest national meteorological service in the world (the Central Institution for Meteorology and Geodynamics (ZAMG) in Austria was founded in 1851 and is the oldest weather service in the world). The first daily weather forecasts made by FitzRoy's Office were published in The Times newspaper in 1860. The following year a system was introduced of hoisting storm warning cones at principal ports when

14803-507: The source's charge generating ability. Water vapor is common in the Solar System and by extension, other planetary systems . Its signature has been detected in the atmospheres of the Sun, occurring in sunspots . The presence of water vapor has been detected in the atmospheres of all seven extraterrestrial planets in the Solar System, the Earth's Moon, and the moons of other planets, although typically in only trace amounts. Geological formations such as cryogeysers are thought to exist on

14934-462: The surface of ice without first becoming liquid water. Sublimation accounts for the slow mid-winter disappearance of ice and snow at temperatures too low to cause melting. Antarctica shows this effect to a unique degree because it is by far the continent with the lowest rate of precipitation on Earth. As a result, there are large areas where millennial layers of snow have sublimed, leaving behind whatever non-volatile materials they had contained. This

15065-416: The surface of several icy moons ejecting water vapor due to tidal heating and may indicate the presence of substantial quantities of subsurface water. Plumes of water vapor have been detected on Jupiter's moon Europa and are similar to plumes of water vapor detected on Saturn's moon Enceladus . Traces of water vapor have also been detected in the stratosphere of Titan . Water vapor has been found to be

15196-413: The surrounding air. The upper atmosphere constitutes the lower temperature level of the atmospheric thermodynamic engine. The water vapor in the now cold air condenses out and falls down to the ground in the form of rain or snow. The now heavier cold and dry air sinks down to ground as well; the atmospheric thermodynamic engine thus establishes a vertical convection, which transports heat from the ground into

15327-427: The telegraph and photography led to the creation of weather observing networks and the ability to track storms. Additionally, scientists began to use mathematical models to make predictions about the weather. The 20th century saw the development of radar and satellite technology, which greatly improved the ability to observe and track weather systems. In addition, meteorologists and atmospheric scientists started to create

15458-545: The temperature of the water molecules. Liquid water that becomes water vapor takes a parcel of heat with it, in a process called evaporative cooling . The amount of water vapor in the air determines how frequently molecules will return to the surface. When a net evaporation occurs, the body of water will undergo a net cooling directly related to the loss of water. In the US, the National Weather Service measures

15589-451: The temperature rises the proportion of water vapor in the air increases, and its buoyancy will increase. The increase in buoyancy can have a significant atmospheric impact, giving rise to powerful, moisture rich, upward air currents when the air temperature and sea temperature reaches 25 °C or above. This phenomenon provides a significant driving force for cyclonic and anticyclonic weather systems (typhoons and hurricanes). Water vapor

15720-406: The transpiration of plants, and various other biological and geological processes. At any given time there is about 1.29 x 10 litres (3.4 x 10 gal.) of water in the atmosphere. The atmosphere holds 1 part in 2500 of the fresh water, and 1 part in 100,000 of the total water on Earth. The mean global content of water vapor in the atmosphere is roughly sufficient to cover the surface of the planet with

15851-440: The unique, local, or broad effects within those subclasses. Water vapor Being a component of Earth's hydrosphere and hydrologic cycle, it is particularly abundant in Earth's atmosphere , where it acts as a greenhouse gas and warming feedback, contributing more to total greenhouse effect than non-condensable gases such as carbon dioxide and methane . Use of water vapor, as steam , has been important for cooking, and as

15982-418: The upper atmosphere, where the water molecules can radiate it to outer space. Due to the Earth's rotation and the resulting Coriolis forces, this vertical atmospheric convection is also converted into a horizontal convection, in the form of cyclones and anticyclones, which transport the water evaporated over the oceans into the interior of the continents, enabling vegetation to grow. Water in Earth's atmosphere

16113-590: The value of his work is in preserving earlier speculation, much like Seneca's work. From 400 to 1100, scientific learning in Europe was preserved by the clergy. Isidore of Seville devoted a considerable attention to meteorology in Etymologiae , De ordine creaturum and De natura rerum . Bede the Venerable was the first Englishman to write about the weather in De Natura Rerum in 703. The work

16244-454: The variables of Earth's atmosphere: temperature, air pressure, water vapour , mass flow , and the variations and interactions of these variables, and how they change over time. Different spatial scales are used to describe and predict weather on local, regional, and global levels. Meteorology, climatology , atmospheric physics , and atmospheric chemistry are sub-disciplines of the atmospheric sciences . Meteorology and hydrology compose

16375-694: The water will be formed as vapor and increase the local humidity, if below the dew point local condensation will occur. Typical reactions that result in water formation are the burning of hydrogen or hydrocarbons in air or other oxygen containing gas mixtures, or as a result of reactions with oxidizers. In a similar fashion other chemical or physical reactions can take place in the presence of water vapor resulting in new chemicals forming such as rust on iron or steel, polymerization occurring (certain polyurethane foams and cyanoacrylate glues cure with exposure to atmospheric humidity) or forms changing such as where anhydrous chemicals may absorb enough vapor to form

16506-417: Was a summary of then extant classical sources. However, Aristotle's works were largely lost until the twelfth century, including Meteorologica . Isidore and Bede were scientifically minded, but they adhered to the letter of Scripture . Islamic civilization translated many ancient works into Arabic which were transmitted and translated in western Europe to Latin. In the 9th century, Al-Dinawari wrote

16637-472: Was considered a subset of astronomy. He gave several astrological weather predictions. He constructed a map of the world divided into climatic zones by their illumination, in which the length of the Summer solstice increased by half an hour per zone between the equator and the Arctic. Ptolemy wrote on the atmospheric refraction of light in the context of astronomical observations. In 25 AD, Pomponius Mela ,

16768-428: Was less important than appeal to the classics and authority in medieval thought. In the thirteenth century, Roger Bacon advocated experimentation and the mathematical approach. In his Opus majus , he followed Aristotle's theory on the atmosphere being composed of water, air, and fire, supplemented by optics and geometric proofs. He noted that Ptolemy's climatic zones had to be adjusted for topography . St. Albert

16899-406: Was not generally accepted for centuries. A theory to explain summer hail was first proposed by Anaxagoras . He observed that air temperature decreased with increasing height and that clouds contain moisture. He also noted that heat caused objects to rise, and therefore the heat on a summer day would drive clouds to an altitude where the moisture would freeze. Empedocles theorized on the change of

17030-399: Was the first work to challenge fundamental aspects of Aristotelian theory. Cardano maintained that there were only three basic elements- earth, air, and water. He discounted fire because it needed material to spread and produced nothing. Cardano thought there were two kinds of air: free air and enclosed air. The former destroyed inanimate things and preserved animate things, while the latter had

17161-536: Was written by George Hadley . In 1743, when Benjamin Franklin was prevented from seeing a lunar eclipse by a hurricane , he decided that cyclones move in a contrary manner to the winds at their periphery. Understanding the kinematics of how exactly the rotation of the Earth affects airflow was partial at first. Gaspard-Gustave Coriolis published a paper in 1835 on the energy yield of machines with rotating parts, such as waterwheels. In 1856, William Ferrel proposed

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