Weather forecast

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The weather forecast is transacted by national and private weather services. The condition for it supplies the meteorology as natural science.

A goal of the weather before legend the prognosis of a condition of the atmosphere is at a certain time at a certain place or an area. Are not actually only meteorological phenomena, which affect themselves at the soil meant, but it the entire atmosphere regarded.

The weather - as physical event - leavesdescribe themselves by appropriate laws of nature. The fundamental idea of a Wetterprognose is it, from passed an already and a current condition of the atmosphere to derive with application of the well-known physical rules, a condition in the future.

The mathematical Konstrukte, which describes these physical rules, is however so-calledNonlinear equations. This means that to relatively large changes in the end of the calculation lead already small change in the starting situation (see also butterfly effect).

It essentially becomes between a manual and/or. differentiated between synoptic weather forecast and a numeric weather forecast, whereby today still a combination of bothProcedure for application comes. This is connected with the fact that also a current numeric prognosis model with approximation methods works, which local characteristics cannot exactly cover, since it counts on a starting situation, which some hours is already past.

The data over the current condition of the atmosphere comeof a network of soil measuring stations, which measure wind velocity, temperature , air pressure and air humidity as well as amounts of precipitation. Additionally also data are used by radio weather probes , meteorological satellites , airliners and weather ships. Thereby the irregular distribution of these observations and measurements, as well as the fact are problematic that in smaller developedCountries and over the oceans it relatively few measuring stations present are.

Table of contents

Web on the left of 6.1 weather forecasts

, history

the estimationthe future weather development interests humans for thousands of years and is the subject of intensive experience and increasing research.

The weather tries to predict is delivered since the antiquity and might still longer go back, if one considers like dependently humans - particularly in the agriculture - ofPrecipitation and temperature were dependent. First delivered recordings originate from that 4. Millenium v. Chr. (Tell Halaf culture and Nisabalied).

So-called lot days - spreads as so-called. “Admits farmer rules” - it carried the circumstance calculation that similar to apparently again and again equal year times running off the times between themto divide further into weather-relevant sections. One assumed on lot days - similar a knot in a decision tree - which weather and the weather, dependent on the condition on this day, would take a certain further process, which from excessive quantities and late recordingsone tried to determine.

Otto von Guericke recognized for the first time the connection between dropping the air pressure and suit of a tempest in the year 1660. A European station net with simultaneous observations for the synoptic method originated in soon after 1800, the North Atlantic ice warning service however only to 1912 after that Titanic - misfortune.

Around 1900 developed many national weather services, which developed a spacious synoptic weather forecast in co-operation. For the 1950er years it by mathemathische computer models and data were improved gradually by meteorological satellite, a net by radio weather probes and weather radar. The relatively reliable roseForecast period in middle widths of approximately 3 days on 4-5 days, which means a noticeable improvement for many sections of the economy and for planning in the agriculture, in traffic or in the building industry.

reliability

rare is so reliable the weather forecast, howthe public and different fields of activity it wish themselves. This is connected particularly with three causes:

  • the incomplete knowledge of the actual happening in the terrestrial atmosphere (incomplete data and/or. from a too weitmaschigen net)
  • the chaotic (not foreseeable) portion in the weather condition
  • (still) of the insufficient accuracythe computational models: for reasons of the computing time and the large resulting data sets air and Wassermassen involved cannot be considered yet with satisfactory accuracy.

Therefore local through „wrong influences make such as mountains and their irregularly formed slopes , effects of different irradiation “computed cloudy appearance, for thatVegetation (forest to field!) or the rock so much out that there is hardly 75-prozentige prognoses over more than 3 days for a certain place.

The theory of the meteorology is by the gas laws, thermodynamics and the science of flow to a large extent clarified, can however throughsmall-scale effects of up to kilometer dimensions not all air movements with sufficient accuracy compute. Thus for example the temperature over dark and bright surfaces can differ by several degrees, something similar steps between sun side and shade side of a mountain comb on or between waters and firm on a sunny daySoil.

weather knowledge

with the progressing of modern weather forecasts has the experience of most humans, which weather without prognoses can refer it over the media generally, to measure in the Vorhinein strongly decreased. In former times nearly each farmer could for at least two days applicablelocal prognoses place. (see also Innerschwyzer Meteoroligist)


and the interested layman?

Up to a certain measure also an experienced layman can provide a prognosis for its environment, which equals those of a whole Land of the Federal Republic at local reliability. Who wants to learn that, findsin the book trade abridged guidances for the interpretation of temperature and air pressure and for the observation of wind and clouds - which show much over the horizontal and vertical air movements. Beside thermometers and barometers one needs in addition only one „healthy observation gift “- wind and kind that Clouds say nearly everything about the horizontal and vertical air movements. But also „simple Wetterstationen “for the desk plus external feelers can deliver programmed prognoses with 60 75% probability of applying.

For the next 1-3 hours one knows - z. B. with the question about local rain, clear Starlit sky or occurring frost - on 80 to 90 per cent come. Even the simplest of all prognoses - today wird's as yesterday - applies in Central Europe to 50 to 70 per cent. Therefore a closer demand can with a weather service, approximately of a farmeror, always a higher hit rate to an insurance with thunderstorm situations bring than „the uniform television weather for a whole Land of the Federal Republic. “

weather prognoses

due to ever better observation and modelling possibilities it seems to be in more near future possible, the weather, thus the weather during a longer period,to predict. See in addition the article weather prognosis.

Web on the left of

weather forecasts of national weather services

prognoses of international federations

prognoses of private Dienstleister

 

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