Medical research

Some fat cells can feel the cold

(Medical Xpress)—To survive in cold environments, mammals burn fat to produce heat. The breakdown of fat helps prevent obesity and related metabolic diseases, such as diabetes. Bruce Spiegelman and his colleagues at Harvard ...

Diseases, Conditions, Syndromes

To predict flu's spread, modelers turn to weather forecasts

Are influenza outbreaks and weather patterns connected? Researchers have long known that flu season occurs in the colder months, and that infection rates drop dramatically as the weather warms. But why? And could weather ...

Neuroscience

Biologist leads pioneering study on stress

A biologist at Louisiana State University conducted a pioneering research study that could help us to better understand the role of dopamine in stress resilience in humans through analyzing wild songbirds. This study could ...

Arthritis & Rheumatism

Low back pain? Don't blame the weather

Australian researchers reveal that sudden, acute episodes of low back pain are not linked to weather conditions such as temperature, humidity, air pressure, wind direction and precipitation. Findings published in Arthritis ...

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Weather

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.

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