Meteorology
The meteorology (from the Greek μετέωρον metéōron 'high in the sky', 'meteor'; and λόγος lógos 'knowledge', ' treated') is the interdisciplinary atmospheric science that studies the weather, the atmospheric environment, meteorological phenomena and the laws that govern them with the support of auxiliary disciplines such as atmospheric physics and atmospheric chemistry.
Meteorology and climatology
The Earth is made up of three fundamental parts: a solid part called the lithosphere, another covered by water called the hydrosphere, and a third, which surrounds the previous two, made up of a gaseous layer called the atmosphere. These are related to each other producing profound changes in their characteristics. The science that studies these characteristics, the properties and the movements of the three fundamental layers of the Earth, is geophysics. In this sense, meteorology is a branch of geophysics whose purpose is the detailed study of the Earth's gaseous envelope and the phenomena that occur in it.
A distinction must be made between current conditions and their evolution (which constitutes the weather) and the average conditions over a long period (which is known as the climate of a place or a region). In this sense, meteorology is an auxiliary science of climatology since the atmospheric data obtained in multiple meteorological stations over a long time are used to define the climate, predict the weather, understand the interaction of the atmosphere with other subsystems, etc. The knowledge of meteorological variations and their impact on the climate has always been extremely important for the development of agriculture, navigation, military operations and life in general.
History of Meteorology
Since ancient times, there is evidence of the observation of changes in the atmosphere and other components associated with the movement of the stars, with the seasons of the year and with related phenomena. The ancient Egyptians associated the Nile flood cycles with the movements of the stars explained by the movements of the gods, while the Babylonians predicted the weather guided by the appearance of the sky. But the term "meteorology" comes from Meteorologica, the title of the book written around 340 B.C. C. by Aristotle, who presents mixed observations and speculations about the origin of atmospheric and celestial phenomena. A similar work, entitled Book of Signs, was published by Theophrastus, a student of Aristotle; it focused on the observation of the phenomena itself rather than on the forecast of the weather.
Subsequent developments in the meteorological field focused on new, more precise instruments being developed and made available. Galileo built a thermometer in 1607, followed by Evangelista Torricelli's invention of the barometer in 1643. The first discovery of the dependence of atmospheric pressure on altitude was made by Blaise Pascal and René Descartes; the idea was later deepened by Edmund Halley. The anemometer, which measures the speed of the wind, was built in 1667 by Robert Hooke, while Horace de Saussure completed the list of the development of the most important meteorological instruments in 1780 with the hair hygrometer, which measured the humidity of the air. Other technological advances, which are known mainly as part of the progress of physics, were the investigation of the dependence of gas volume on pressure, leading to thermodynamics, and Benjamin Franklin's experiment with the kite and lightning. Franklin was also the first to record weather conditions accurately and in detail on a daily basis, as well as to make weather forecasts on that basis.
Global atmospheric circulation was first correctly defined by George Hadley, with a study of the trade winds in 1735. Initially, this was a partial understanding of how the Earth's rotation influences the kinematics of airflows of air. Later (in the 19th century), the full extent of the large-scale interaction behind the force of the pressure gradient and the deflection caused by the Coriolis effect, which together give rise to the complex three-dimensional motion of the wind, was understood. The deflection force owes its name to Gaspard-Gustave Coriolis, who in a publication from 1835 described the results of a study on the energy produced by the machine with rotating parts, such as the water path of mills. In 1856, William Ferrel hypothesized the existence of a "circulation cell" in mid-latitudes, in which the air is deflected by the Coriolis force, creating the main westerly winds. The synoptic observation of the weather was still complex due to the difficulty of classifying certain climatic characteristics such as clouds and winds. This problem was solved when Luke Howard and Francis Beaufort introduced a classification system for clouds (1802) and wind force (1806), respectively. The real turning point was the invention of the telegraph in 1843, which made it possible to begin exchanging weather information at unmatched speeds.
At the beginning of the 20th century, progress in the understanding of atmospheric dynamics led to the birth of weather forecasting based on mathematical calculations. In 1922, Lewis Fry Richardson published Weather prediction by numerical process, which described how removing minor variants from the fluid dynamics equations governing atmospheric fluids made it easy to find numerical solutions, despite that the number of calculations needed was very large. In the same period, a group of Norwegian meteorologists led by Vilhelm Bjerknes developed a model to explain the generation, intensification and dissolution of mid-level cyclones, introducing the idea of the weather front and subdivisions of the masses. of air. The group included Carl-Gustaf Rossby (who was the first to explain large-scale atmospheric flow in terms of fluid dynamics), Tor Bergeron (the first to understand the mechanism of rain formation), and Jacob Bjerknes.
In the 1950s, computer numerical computation experiments proved feasible. The first weather forecasts made with this method used barotropic models (that is, they represented the atmosphere as a single layer) and could successfully predict the large-scale motions of Rossby waves. In the 1960s, the chaotic nature of the atmosphere was understood by Edward Lorenz, founder of the field of chaos theory. The mathematical advances obtained in this field were taken up by meteorology and contributed to stabilizing the predictability limit of the atmospheric model.
Climate models
In recent years, high-resolution climate models have been developed, used to study long-term changes, especially current climate change. However, one must be careful in this regard: climate is the long-term statistical average of meteorological data obtained at weather stations located in a given area that present similar characteristics and define a given climate. This is done in all weather types around the world. But these climatic types cannot be condensed in certain models because their long-term variations must be obtained a posteriori from said long-term variations. In other words: the meteorological information obtained in a multitude of meteorological stations around the world serves, in an inductive way, to establish the climatic characteristics with their variants in the entire terrestrial surface and once we obtain them, we can study the climatic changes that have occurred in the past until the moment in which they are analyzed, but we could not use this information towards the future because meteorology and climatology work at different scales, as pointed out by a scientific institution as careful in its analyzes as NASA when pointing out the possible relationship existing between the severe cold wave in Europe and North America in the first three months of 2014 (with extreme temperatures so low that they had never been recorded in many places) and the climate models that tell us about global warming within of the atmosphere.
Thus, in the analysis made by NASA of the cold wave so intense that the northern hemisphere (Europe and North America) has experienced, it is pointed out that we must be very cautious when speculating the relationship between meteorology and climatology since the two sciences operate on different time scales. This analysis indicates that:
In the United States, the cold spell generated public debate about whether such events disprove global warming or if, in fact, they are exacerbated or caused by it. However, most climate scientists and meteorologists are wary of drawing such connections between climate and weather, which operate on different time scale.In the United States, the cold wave (referring to that of the beginning of 2014) has generated a public debate about weather time and whether these intense cold weather events land the idea of global warming or, in fact, exacerbated or even caused by that idea. However, most climate scientists and meteorologists are very careful in inferring those connections between time and climate, which operate on different time scales. (from commentary to NASA maps in the article What Goes Around Comes Around10 January 2014).
The progress of meteorology in recent times (21st century)
The technological development obtained in the improvement of instruments and devices for detection and data processing has revolutionized the science of meteorology, especially with regard to the use of meteorological satellites, airplanes of the so-called hurricane hunters, drones for purposes also meteorological, satellites that collect information on marine currents, surface temperature of seas and oceans and, above all, the collection, processing of data and projection and meteorological forecasts. Of course, all these advances began in the last decades of the XX century (remember what the launch of the artificial satellite TIROS meant I (Television Infra-Red Observation Satellite) in 1960 but this was only the starting point of a new era, which has left the state of science (in this case of meteorology) far behind, which continues to spread in schools and in the specialized bibliography, and we are not only lagging behind in the field of scientific and technical training, but also in research and development programs, although in the latter there is a great diversity of situations worldwide. []
Branches of Meteorology
Meteorology includes the study (description, analysis and prediction) of large-scale daily variations of atmospheric conditions or Synoptic Meteorology, the study of the movements in the atmosphere involved in atmospheric dynamics and their temporal evolution based on the principles of fluid mechanics (Dynamic Meteorology, currently closely related to synoptic meteorology), the study of the structure and composition of the atmosphere, as well as electrical, optical, thermodynamic, radioactive and other properties (Physical Meteorology), the variation of meteorological elements near the Earth in a small area (Micrometeorology), the specific study of meteorological phenomena in the intertropical zone (Tropical Meteorology) and many other phenomena. The study of the highest layers of the atmosphere (higher than 20 or 25 km) usually involves the use of special techniques and disciplines, and is called aeronomy. The term aerology applies to the study of atmospheric conditions at any altitude.
Applied meteorology
Applied meteorology aims to constantly collect a maximum of data on the state of the atmosphere and, in the light of the knowledge and laws of theoretical meteorology, analyze, interpret and obtain practical deductions, especially to forecast the weather with the maximum advance. Since the atmosphere is an immense gaseous mass subject to constant variations, which most of the time occur at a regional level, its state at a given moment can only be known if a sufficiently dense network of observation posts or stations is available. meteorological stations, distributed throughout all the regions of the globe, which at fixed times carry out the same measurements (temperature, pressure, humidity, wind, precipitation, solar radiation, cloudiness, etc.) and transmit the results to the centers in charge of using them.
Objects of study
Those concerning the weather and weather forecasting. His field of studies covers, for example, the repercussions on Earth of solar rays, the radiation of heat energy through the earth's soil, the electrical phenomena that occur in the ionosphere, those of a physical, chemical and thermodynamic nature that affect the atmosphere, the effects of time on the human organism, etc.
The topics of theoretical meteorology are based, first of all, on a precise knowledge of the different layers of the atmosphere and the effects that the sun's rays produce on it. In particular, meteorologists establish the energy balance that compares the solar energy absorbed by the Earth with the energy radiated by it and dissipated in interstellar space. Any further study implies, moreover, a knowledge of the repercussions that the movements of the Earth have on time, climates, the succession of seasons. The two main parameters related to atmospheric air also give rise to in-depth theoretical studies: pressure and temperature, whose gradients and variations must be known with the greatest precision.
With regard to the evolution of time, the study of atmospheric water in its three forms: (gaseous, liquid and solid), as well as the conditions and circumstances that govern its changes of state (latent heat of evaporation, melting, etc.), the stability and instability of humid air, clouds and precipitation.
Another fundamental branch strives to determine the laws that govern the general circulation of the atmosphere, the formation and movements of air masses, wind and currents in general, air turbulence, the conditions in which they form and move fronts, anticyclones, cyclones, and other disturbances, as well as the processes that give rise to meteors.
Meteorological equipment and instruments
In general, each science has its own laboratory equipment and instruments. However, meteorology is a short discipline in laboratory equipment and broad in field observation equipment. In some respects this may seem good, but in reality it can lead simple observations to mislead.
In the atmosphere, there are many objects or qualities that can be measured. Rain, for example, has been observed anywhere and forever, being one of the first phenomena to be measured historically.
Weather stations
- Main article: Weather station
A weather station is a facility designed to regularly measure and record various weather variables. These data are used both for the elaboration of meteorological predictions from numerical models and for climate studies. It is equipped with the main measuring instruments, among which are the following:
- Anemmeter (measure wind speed)
- Veleta (sign the direction of the wind)
- Barometer (measure air pressure)
- Heliograph (minds the insolation received on the ground surface)
- Hygrometer (mide moisture)
- Pyrometer (minds solar radiation).
- Pluviometer (waterfall)
- Environmental thermometer (mode temperature in certain hours of the day])
- Underground thermometer (mode temperature from 5 to 100 cm deep)
- Visiblimeter (mide visibility)
These instruments are protected in a ventilated box, called a weather shelter or Stevenson screen, which keeps direct sunlight away from the thermometer and wind away from the hygrometer, so that the measurements are not disturbed. of these.
The more numerous the weather stations, the more detailed and exact the situation is known. Nowadays, a large number of them have specialized personnel, although there are also a number of automatic stations located in inaccessible or remote places, such as polar regions, uninhabited islets or mountain ranges. In addition, there are meteorological frigates, ships that contain a very complete weather station on board and which are assigned a specific position in the middle of the ocean. However, it is necessary to emphasize that, with the great growth of the urban population since the end of the XIX century, most of Weather stations are currently located in urban areas, either because they are located in new cities or because they are located in rural populations absorbed by large urban centers in their expansion process, with which there is a bias introduced by urban microclimates that give foot to corroborate, erroneously, the increase in temperatures on a global scale (which would be proof of global warming).
Meteorological satellites
- Main article: Meteorological satellite
Weather satellites are a type of artificial satellite used to monitor Earth's weather and climate, although they are also capable of seeing city lights, forest fires, pollution, auroras, sand and dust storms, ocean currents etc. Other satellites can detect changes in the Earth's vegetation, the state of the sea, the color of the ocean and the snowy areas.
The El Niño phenomenon and its effects are recorded daily in satellite images. The Antarctic ozone hole is drawn from data obtained by weather satellites. Collectively, weather satellites from China, the United States, Europe, Canada, India, Japan, and Russia provide a near-continuous observation of the global state of the atmosphere, albeit at a very detailed scale where cloud patterns and intensity can be identified. circulation of the winds, as well as the energy flows generated by meteorological phenomena.
The weather forecast
Several times a day, at fixed times, the data from each weather station, from ships and from satellites reach the regional services in charge of centralizing, analyzing and exploiting them, both to advance meteorology and to establish key weather forecasts for the coming days. As the observations are repeated every 3 hours (according to world synoptic time), the succession of maps and diagrams allows us to appreciate the synoptic evolution: we can see how disturbances form or resolve, if they are rising or lowering the pressure and temperature, if the force of the wind increases or decreases or if it changes direction, if the air masses that go towards that region are humid or dry, cold or warm, etc. It thus seems quite easy to predict the trajectory that the disturbances will follow and to know what the weather will be like in a certain place after one or several days. In reality, the atmosphere is a gigantic, turbulent, three-dimensional gaseous mass whose evolution is influenced by so many factors that one of these factors can unpredictably exert a preponderant action that upsets the expected evolution in an entire region. Thus, the forecast of the weather is less uncertain the less the anticipation and the smaller the space to which it refers. For this reason, the forecast is classified as micrometeorological, mesometeorological or macrometeorological, depending on whether it covers a space of 15 km, 15 to 200 km, respectively. km or more than 200 km. The forecasts are formulated in the form of bulletins, some of which are intended for the general public and others for certain branches of human activity and air and sea navigation, agriculture, construction, tourism, sports, regulation of water courses, certain industries, prevention of natural disasters, etc.