meteorology
meteorology ( Ancient Greek μετεωρολογία meteorology “Investigation of supernatural things or celestial bodies” [1] ) is the study of physical and chemical processes in the atmosphere and also includes its most well-known areas of application – the Weather forecast and the Climatology . [2] [3]
About atmospheric physics, the Climate research and improving weather forecasting methods, meteorology also studies chemical processes (e.g. Ozone formation, Greenhouse gases ) in the atmosphere and observes atmospheric Celestial phenomena . It is one of the earth sciences counted and is at the universities (see Meteorology studies ) often the institutes for geophysics or the respective factorial for physics.
History of Meteorology
Origins
Weather observation was already for our as Nomads living ancestors. Observing and recording the local weather was – and still is – an important basis for farmers to make fundamental decisions: when to sow man, when do you harvest.
· The earlier you sow, the longer the possible growing season until harvest; however, earlier sowing also risks losses due to weather effects on the young seeds.
· The later you harvest, the greater the yield. However, it may be better to harvest a little earlier, for example, to protect your crops from an approaching storm or period of bad weather.
Weather observation and research can also serve military purposes. For example, naval battles An accurate forecast of wind direction and strength is useful or even crucial.
The Discovery of America was the beginning of the "conquest of the world's oceans." The increasing intercontinental shipping traffic brought many new insights into weather phenomena. On board the ships, the weather was observed in detail and recorded in logbook recorded.
Early theoretical approaches provided Albertus Magnus : In his treatise De natura locorum he described the dependence of the properties of a place on its geographical location. Such approaches continued to have an impact, visible, for example, in a brief exposition of theoretical climatology by the Viennese astronomer Georg Tannstetter (1514). [4]
The first revolution in meteorology began between 1880 and 1900, when the meteorological services of individual countries were able to exchange their weather data via wired and wireless telegraphy, thus enabling timely data comparison. This made synoptic weather maps possible for the first time.
20th century [
After the invention of aircraft (the first Montgolfière flew in 1783) balloons were used to better explore the weather in the lower atmosphere (see also Weather balloon ; Main article: Chronology of Aviation ).
Since the invention of powered flight in 1909, the importance of Weather research Aircraft became important research tools, allowing large-scale observation and photography of weather (e.g., "clouds from above") and the measurement of weather data.
During the First World War, numerous aircraft were used; initially for Reconnaissance ; later also for dropping bombs. Aircraft technology (e.g. maximum altitude, range, speed) developed very quickly (see e.g. Air Force (German Empire) , French Air Force , Royal Air Force ).
During the Second World War, the system developed in the 1930s radar used; it enabled the acquisition of new types of weather observation data (see Weather radar ).
During the Second World War, all belligerent nations massively increased their air forces (they proved to be decisive for the war ); the first jet aircraft were built; large amounts of weather data were collected. They developed and built Fighter aircraft that have particularly high Service ceiling heights could reach. For example, the German aircraft Ta 152 or the Soviet Yak-9PD about 14 km altitude; just a short time before, a maximum altitude of about 4 km could be reached.
The Wehrmacht maintained from 1941 to 1945 Weather stations in the Arctic .
After the war, the Cold War ; many countries made great efforts to research the weather (e.g. the US project "Thunderstorm"). In addition, they developed and built Reconnaissance aircraft that could fly so high that they could not be reached by enemy ground-based missiles at that time. The Lockheed SR-71 spy plane has a service ceiling of 24,385 meters.
Weather research at high altitudes was primarily used to Space travel , especially manned space flight (see also The Space Race in the Cold War ), and the development of Intercontinental ballistic missiles . In 1957, the Soviet Union launched the first functional intercontinental ballistic missile ; a few weeks later it brought Sputnik 1 and Sputnik 2 two satellites into space, triggering the “ Sputnik shock ” in the West.
A significant milestone for weather research was the use of Weather satellites . The first was launched in 1960; from 1960 to 1966, the USA launched a total of 10 TIROS satellites. From 1968 to 1978, they launched eight (including one failure). NIMBUS satellites . They also had infrared cameras on board. These allow us to film weather phenomena (e.g. clouds) – even at night – and to quantify how much heat heated parts of the Earth's surface (land masses, and to a lesser extent water surfaces) radiate into space at night (see Earth#Global energy balance ). Satellite meteorology is considered an independent branch of meteorology.
Well-known weather researchers included:
· Karl Ludwig Gronau (1742–1826)
· Wilhelm Jacob van Bebber (1841–1909)
· Ludwig Friedrich Kämtz (1801–1867)
· Karl Schneider-Carius (1896-1959)
21st century
A quantum leap in weather forecasting is made possible by rapid advances in Electronic data processing (“EDP”) and the rapidly growing Computing power . Ever-increasing amounts of data from ever-increasing numbers of measuring stations are being processed. The sophisticated algorithms used to evaluate them require massive computing power. This makes forecasts more precise and also more detailed in their local resolution. [5] [6] [7]
General
Although the main focus of meteorology is on the large-scale dynamic processes within today’s Earth's atmosphere However, the models developed as part of a better understanding of weather dynamics are also applicable to other Systems transferable.
Therefore, limited Indoor climates or Urban climates , extraterrestrialatmospheres or atmospheres of past Geological era ( Paleoclimatology ) are among the objects of study in meteorology. However, these mostly only play a major role in research, where they also serve as a "playground" for improving models that describe the current Earth's atmosphere. Therefore, attempts are made to create a secure data basis through precise observations of the Earth's atmosphere and, at the same time, to use these data for the creation of an ever better understanding of meteorological Processes to be used. [9]
Many methods, approaches and ideas of dynamic meteorology originate from the general Fluid dynamics and find further application in Oceanography , geophysics and Engineering as well as in almost all environmental sciences .
Meteorology is – apart from the Weather observation (Meteorology) – a young Science . It has an exceptionally interdisciplinary approach, thus combining many different disciplines. Scientific disciplines used or touched upon by meteorology include:
· physics ( Fluid dynamics , Thermodynamics , Electromagnetism , Optics )
· mathematics ( Numerics , partial differential equations , Functional analysis , Linear Algebra )
· Computer science (programming languages, Algorithmics , treatment of large Data volumes, just-in-time processes, visualization)
· Chemistry ( Ozone chemistry, Nitrogen chemistry, Carbon chemistry)
· earth sciences ( Climatology , Paleoclimatology , Glaciology )
· biology ( Climate Impact , influence of vegetation on weather/climate)
Meteorology can be divided into different branches, some of which overlap considerably.
|
Sub-areas |
||
|
according to procedure |
according to spatial conditions |
according to applied techniques |
|
general meteorology |
||
|
experimental meteorology |
||
|
|
Micrometeorology |
|
|
Maritime Meteorology |
|
|
|
Alpine Meteorology |
|
|
|
Glacial meteorology |
|
|
|
|
||
|
|
||
|
|
||
This list is not exhaustive. In particular, meteorology deals not only with the troposphere , the lowest layer of the atmosphere, but also with stratosphere and to a limited extent even with Mesosphere and Thermosphere .
Data sources and data quality
The most important task and at the same time the biggest problem of meteorology as empirical Science consists in the collection, processing, and especially the evaluation and comparison of data. Unlike other natural sciences, in meteorology, controllable laboratory conditions can only be created for a small minority of questions. Meteorological data collection is therefore generally linked to the framework conditions provided by nature, which reproducibility of measurement results and in particular the reductionism on closed questions that can be answered by measurement.
The most important Basic sizes are:
· Wind direction or main wind direction
· Wind speed (phenomenological) or Wind speed ( vector , horizontal and vertical)
· Albedo
Many of these measurements are Climate gardens raised.
These quantities are provided in various standard formats for data exchange. In aviation, for example, the Meteorological Aviation Routine Weather Report (METAR) code is used for the transmission of meteorological data from land stations of the SYNOP FM12/13 code, data obtained at sea is encrypted with the ship code. Classification Different tools can be used to determine the characteristics of a parameter. For example, for wind, the Beaufort scale or the Visual marker table a weather station. Meteorological data are collected hourly or 2 to 3 times a day (at 7, 12, 19 or 7 and 19) depending on the status of a weather station in the measuring network (as a climate station, precipitation station or synoptic station) and are exchanged internationally and processed nationally. The data are processed by a variety of meteorological measuring devices The following list only lists the most important examples from this variety:
· or thermograph (Temperature or temperature recorder)
· hygrometer or Hygrograph (Humidity or air humidity recorder)
· Thermohygrograph (Temperature/Humidity Recorder)
· barometer or barograph (air pressure gauge or air pressure recorder)
· Rain gauge or rain gauge/ombrometer (type of precipitation/amount of precipitation)
· anemometer (wind speed) or windsock (wind speed/wind direction)
· weather vane (wind direction)
· SODAR (wind speed/wind direction)
· Aerograph (not common in Europe) or the Anemograph or recorder for wind direction and wind speed
· Precipitation radar (Doppler radar )
· Lysimeter (Infiltration-evaporation ratio → Evapotranspiration )
· Net radiometer / Netto radiometer ( Radiation balance meter )
· Pyranometer (Global radiation sensor)
· Albedometer (Reflex radiation meter)
Numerous problems arise from the variety of measuring instruments, the type of measured quantities and the purposes of their use.
For the Measurand precipitation For example, various measuring devices for measuring rain, dew, snow and hail are widely used and have been tried and tested. For methodological reasons, the measurement of liquid ( rain , dew ) and solid ( snow , A distinction is made between precipitation (e.g., hail ) and precipitation, and the measured quantity is therefore classified according to the recorded precipitation types. The measurement accuracy of the commercially available methods for determining liquid precipitation can be estimated at approximately 30%; that for solid precipitation is no better. Other hydrometeors are recorded by sucking in a volume of air or by depositing them on rods and determined volumetrically.
The quality of precipitation measurements is primarily influenced by the parameters wind, air temperature, installation height above ground, evaporation, and installation location. The question of their comparability and the necessary corrections is the subject of scientific discussion; numerous comparisons have already been carried out for a wide variety of precipitation gauges (see WMO or CIMO ).
The measurement of other meteorological quantities is also subject to similar, albeit lesser, problems: for example, for a long time the vertical component of wind speed could not be correctly measured and even today the measurement of vertical Gradients very complex. Therefore, one usually restricts oneself to ground measurements, using standardized ground distances of usually two or ten meters, depending on the measured value. It should be noted that a single meteorological measurement is almost meaningless, and weather dynamics on larger spatial scales can only be understood and forecasted through a large number of measurements. However, these measurements must be comparable, which is why the standardization and standardization of measuring instruments and measurement methods in meteorology is very important, but due to various practical problems, it can only be implemented to a limited extent. Therefore, it is also referred to as measurement networks and the establishment of Weather stations . These usually follow the VDI guideline 3786 or others, partly worldwide by the World Meteorological Organization standardized guidelines.
In addition to the spatial comparability of data, which is necessary for weather forecasting, there is also the temporal comparability, which plays a crucial role for climate forecasts, among other things. If the development of measuring instruments and thus the Measurement accuracy at the analysis If some very old data are not taken into account, these data are scientifically almost worthless, which is why outdated measuring instruments that have not been changed for decades are still widely used worldwide. This is also a question of cost, as it is not always sensible to use the most modern and therefore most expensive measuring instruments, as these are only affordable for individual countries or institutes. Furthermore, every change of measuring equipment entails a change of the Data quality linked, which in the case of longer and very valuable measurement series from many decades to a few centuries easily lead to wrongly postulated or interpreted This can lead to changes in trends , so a higher number is often used for comparability. accuracy waived. In the case of a global warming of a few degrees Celsius These very old data are usually of little use, as their measurement error alone usually exceeds the effect of these possible temperature changes. A large part of the arguments of so-called " climate skeptics " are based on this partly controversial data set, but other natural climate archives also exist. with much more accurate data over very long periods of time. The discussion about the validity of temperature records has led to the BEST project at the University of Berkeley busy.
This creates the need to critically examine measurement data and correctly classify it, due to site-specific, personnel, and measurement-technical factors. In meteorology, spatial data analysis is the key to this. in the foreground, in the otherwise closely related climatology, however, temporal data analysis ( time series analysis ) plays the main role.
Radiation measurement
The extraction of physical quantities from measurements in various areas of the electromagnetic spectrum is a challenge that can only be met with great technical effort and the use of models succeeds.
Satellite measurement [
An important tool for meteorologists, especially the Satellite meteorology , today form the Satellites , especially the Weather- and Environmental satellites . A distinction is made between geostationary satellites , which are anchored stationary above the Earth at an altitude of 36,000 km, and satellites which are based on a LEO orbit the Earth at intervals of 400 to 800 km. Due to the large-scale collection of measurement data, satellites can capture and ultimately understand global relationships.
Today, only satellites make it possible to obtain information about the atmosphere in the form of global, daily-resolved observations. In particular, the state and composition of the upper atmosphere (stratosphere, mesosphere, thermosphere) can only be effectively studied through the use of satellites.
High spatial and temporal resolution of satellite data is desirable because it enables effective monitoring of atmospheric components and their changes. For example, satellite data are valuable in monitoring the development of ozone holes, as satellite measurements allow for very precise estimations of ozone concentrations per altitude and per day. Many other atmospheric Trace gases are monitored in this way (for example methane , carbon dioxide , water vapor ), but also Pressure and temperature in theatmosphere can thus be determined very precisely and with spatial accuracy. The ongoing development of instruments and the trend toward small, highly specialized satellites also makes it possible to track anthropogenically induced disturbances in the atmospheric composition. Combined with in-situ measurements (e.g., by balloon) and model calculations, this gradually creates an increasingly complete picture of the state of the Earth's atmosphere.
Tropospheric satellite data are used to gain insights into Regions which are not accessible by any other measurement method. For example, precipitation estimates or wind speed determinations over the Oceans . There is no dense measuring network available and for a long time large-scale Data extrapolations are dependent on this, which even today means that in strongly maritime weather conditions, for example on the west coast North America , much lower Predictive qualities can be achieved than in continental weather conditions. All non-satellite-based Data collection on the ocean come from ship or Buoy measurements or from measuring stations on isolated Islands . Knowledge of weather conditions over the oceans can therefore lead to an improvement in the overall forecasts of precipitation events on This is especially important for monsoon affected countries, such as India , a vital information.
Satellite data are used, for example via so-called data assimilation, as a basis in the climatology used to improve or support their models and to ensure comprehensive and consistent Data collection to enable.
Working with satellite data requires extensive knowledge of Data processing and the associated technology and techniques (e.g., efficient programming). Large amounts of data (now in the terabyte range) must be received, forwarded, stored, processed, and archived.
Models and simulations [
Especially in climatology ( climate model ), but also in meteorology ( numerical weather prediction ) and remote sensing play Models play a prominent role. They gain their importance through various factors:
· With increasing development of Measurement technology and the increasing demand for weather forecasts, the amount of data is also increasing This makes a written Evaluation the data on Weather maps no longer sufficient. Simplified models and computer simulations are therefore faster, more cost-effective, and enable comprehensive data analysis.
· The periods in which many effects, for example Sea level fluctuations occur over an enormously long period and can only be simulated using models. They are not directly observable and, in addition, there are no continuous and qualitatively sufficient measurement series for such periods. Meteorologists therefore generally have no Laboratory in which they can conduct measurements, and therefore rely on theoretical models. These models must then be compared with observed effects. Exceptions include, for example, the climate chamber. AIDA of the Karlsruhe Research Center and the climate chamber at Jülich Research Center .
The design of models is just as challenging as their content design. Only models that reflect nature describe as adequately as possible, are useful in both research and practice. Since such models can easily occupy entire data centers due to the complexity of the modeled system, an efficient Algorithmics , i.e. simplifying nature statistical Assumption is an important aspect of model development. Only in this way can computing time and thus costs be kept manageable.
In the 1920s, the mathematician Lewis Fry Richardson Methods have been developed to help the enormous complexity mathematical meteorological models. These are still often the basis for meteorological Simulations ( simulation model ) on Supercomputers . It is not without reason that these are often used to simulate weather and climate dynamics, although they quickly reach their limits, despite their sometimes gigantic size.
There are different types of atmospheric models roughly distinguish: Radiative transfer models (e.g. KOPRA), Chemical transport models (e.g. ECHAM ) and dynamic models. However, the trend is toward integrated models or "world models" that depict the entire natural world (SIBERIA 2).
As is the case everywhere in physical modeling, the improvement of model quality involves the use of statistical methods, experimental observations, new ideas, etc. A well-known example of this is the development that has led to the realisation that changes in trace gas quantities in the atmosphere (e.g. Carbon dioxide or Ozone ) leads to an “unhealthy” heat development of the biosphere can lead to (e.g. greenhouse effect , cooling of the Stratosphere ). The discovery of the ozone hole and increasing the attention of scientists to the related Atmospheric chemistry falls into this category.
The simplest meteorological model, and at the same time the first test for all newly developed weather forecasting models, is the simple extrapolation of the current weather to the future. The simple principle of constant weather applies here; that is, one assumes that the weather the next day will be the same as the current day. This is called a persistence forecast. Since weather conditions often remain virtually constant for long periods of time, this simple assumption already has a probability of success of approximately 60%.