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>
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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>
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Wiktionary's word of the day:
bosky (adj):
Having lots of bushes or shrubbery; bushy
<http://en.wiktionary.org/wiki/bosky>
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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>