Weather

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Weather is a set of all the phenomena occurring in a given atmosphere at a given time. Weather phenomena lie in the troposphere. Weather refers, generally, to day-to-day temperature and precipitation activity, whereas climate is the term for the average atmospheric conditions over longer periods of time. When used without qualification, "weather" is understood to be the weather of Earth.

Weather occurs due to density (temperature and moisture) differences between one place and another. These differences can occur due to the sun angle at any particular spot, which varies by latitude from the tropics. The strong temperature contrast between polar and tropical air gives rise to the jet stream. Weather systems in the mid-latitudes, such as extratropical cyclones, are caused by instabilities of the jet stream flow. Because the Earth's axis is tilted relative to its orbital plane, sunlight is incident at different angles at different times of the year. On Earth's surface, temperatures usually range ±40 °C (100 °F to −40 °F) annually. Over thousands to hundreds of thousands of years, changes in Earth's orbit affect the amount and distribution of solar energy received by the Earth and influence long-term climate

Surface temperature differences in turn cause pressure differences. Higher altitudes are cooler than lower altitudes due to differences in compressional heating. Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location. The atmosphere is a chaotic system, so small changes to one part of the system can grow to have large effects on the system as a whole. Human attempts to control the weather have occurred throughout human history, and there is evidence that human activity such as agriculture and industry has inadvertently modified weather patterns.

Studying how the weather works on other planets has been helpful in understanding how weather works on Earth. A famous landmark in the Solar System, Jupiter's Great Red Spot, is an anticyclonic storm known to have existed for at least 300 years. However, weather is not limited to planetary bodies. A star's corona is constantly being lost to space, creating what is essentially a very thin atmosphere throughout the Solar System. The movement of mass ejected from the Sun is known as the solar wind.

For more information about Weather, read the full article at Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.

News tagged with weather

Venezuela turns to cloud-seeding to battle drought

Space & Earth / Earth Sciences

Nov 29, 2009 | not rated yet | 1

(AP) -- Hugo Chavez says he is starting to "bombard" clouds now that Cuba has provided Venezuela with cloud-seeding help in an effort to produce rain and alleviate the effects of a severe drought.

NRL Sensor Observes First Light

Space & Earth / Space Exploration

Dec 02, 2009 | not rated yet | 0

The Special Sensor Ultraviolet Limb Imager (SSULI) developed by NRL's Spacecraft Engineering Department and Space Science Division, launched October 18, 2009 on the U.S. Air Force Defense Meteorological Satellite ...

Search results for weather

Study: Slowdown in warming last year not permanent

Space & Earth / Earth Sciences

Dec 04, 2009 | 3.3 / 5 (10) | 19

(AP) -- Cooler temperatures in North America last year do not mean global warming is easing, government and academic scientists said Friday.

Texas AgriLife researchers working to develop heartier, better-adapted crops

Biology / Other

Dec 04, 2009 | not rated yet | 0

Dr. Daniel Leskovar, a Texas AgriLife Research plant physiologist at the Texas AgriLife Research and Extension Center in Uvalde, has been investigating ways to help vegetable plants make a less stressful transition from the ...

Gifts for your favorite geek

Electronics / Consumer & Gadgets

Dec 04, 2009 | not rated yet | 1

In the spirit of the season, I've picked out 10 geeky gifts that cost less than $100. Some are practical. Some are fun. All would be good additions to your gift list for friends and family -- or your own wish list. (Ranked ...

Crew plans to cut rope to free Hawaii whale

Biology / Plants & Animals

Dec 04, 2009 | 5 / 5 (1) | 0

(AP) -- Marine sanctuary officials planned to return to Hawaii waters with modified equipment Friday to try to cut loose a young humpback whale entangled in several hundred yards of heavy plastic rope.

AP sources: Comcast to pay $13.75B for NBC stake (AP)

Comcast aims to reshape entertainment with NBC

Technology / Business

Dec 03, 2009 | 3.5 / 5 (2) | 0

(AP) -- Comcast Corp. announced Thursday it plans to buy a majority stake in NBC Universal for $13.75 billion, giving the nation's largest cable TV operator control of the Peacock network, an array of cable ...

Researchers look at water-energy impacts of climate change

Space & Earth / Environment

Dec 01, 2009 | 4 / 5 (4) | 1

(PhysOrg.com) -- Climate projections for the next 50 to 100 years forecast increasingly frequent severe droughts and heat waves across the American Southwest, sinking available water levels even as rising mercury drives up ...

ISS astronauts land safely in Kazakhstan

Space & Earth / Space Exploration

Dec 01, 2009 | 5 / 5 (3) | 0

A space capsule carrying a Belgian, a Canadian and a Russian landed safely in the steppes of Kazakhstan on Tuesday after the trio spent half a year on the International Space Station (ISS).

First comprehensive review of the state of Antarctica's climate

Space & Earth / Earth Sciences

Dec 01, 2009 | 3.7 / 5 (11) | 3

The first comprehensive review of the state of Antarctica's climate and its relationship to the global climate system is published this week by the Scientific Committee on Antarctic Research (SCAR). The review - Antarctic ...

Winds drive icebergs away from New Zealand

Space & Earth / Earth Sciences

Dec 01, 2009 | 4 / 5 (2) | 0

(AP) -- Strong westerly winds in the southern Pacific Ocean have driven scores of icebergs originally headed toward New Zealand to the east, away from the country, an oceanographer said Tuesday.