110px|Climate models are systems of differential equations based on the basic laws of physics, fluid motion, and chemistry. Atmospheric models calculate winds, heat transfer, radiation, relative humidity, and surface hydrology at each grid point, and evaluate interactions with neighboring points.
Numerical weather prediction uses mathematical models of the atmosphere and oceans to predict the weather based on current weather conditions. A number of global and regional forecast models are run in different countries worldwide, using current weather observations relayed from radiosondes or weather satellites as inputs to the models. Mathematical models based on the same physical principles can be used to generate either short-term weather forecasts or longer-term climate predictions. Manipulating the vast datasets and performing the complex calculations necessary to modern numerical weather prediction requires some of the most powerful supercomputers in the world. Even with the increasing power of supercomputers, the forecast skill of numerical weather models only extends to about six days. Factors affecting the accuracy of numerical predictions include the density and quality of observations used as input to the forecasts, along with deficiencies in the numerical models themselves. To quantify the large amount of inherent uncertainty remaining in numerical predictions, ensemble forecasts have been used since the 1990s to help gauge the confidence in the forecast, and to obtain useful results farther into the future than otherwise possible. (more...)
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Read the rest of this article: http://en.wikipedia.org/wiki/Numerical_weather_prediction
_______________________________ Today's selected anniversaries:
955:
Forces under Otto I were victorious at the Battle of Lechfeld near present-day Augsburg, Germany, holding off the incursions of the Magyars into Central Europe. http://en.wikipedia.org/wiki/Battle_of_Lechfeld
1270:
Yekuno Amlak deposed the last Zagwe king and seized the imperial throne of Ethiopia, beginning the reign of the Solomonic dynasty that would last for more than 700 years. http://en.wikipedia.org/wiki/Yekuno_Amlak_of_Ethiopia
1793:
The Louvre , the most visited art museum in the world, officially opened with an exhibition of 537 paintings. http://en.wikipedia.org/wiki/Mus%C3%A9e_du_Louvre
1953:
First Indochina War: The French Union withdrew its forces from Operation Camargue against the Viet Minh in central modern-day Vietnam. http://en.wikipedia.org/wiki/Operation_Camargue
1988:
Japanese-American internment: The Civil Liberties Act of 1988 became law, authorizing US$20,000 in reparations to each surviving internee. http://en.wikipedia.org/wiki/Civil_Liberties_Act_of_1988
_____________________________ Wiktionary's word of the day:
bosky (adj): Having lots of bushes or shrubbery; bushy http://en.wiktionary.org/wiki/bosky
___________________________ Wikiquote quote of the day:
The one thing we know about torture is that it was never designed in the first place to get at the actual truth of anything; it was designed in the darkest days of human history to produce false confessions in order to annihilate political and religious dissidents. And that is how it always works: it gets confessions regardless of their accuracy. --Andrew Sullivan http://en.wikiquote.org/wiki/Andrew_Sullivan