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Weather - Basic mechanism, Terrestrial, Forecasting

air pressure theory atmosphere

Weather occurs when there is a temperature change, resulting in a difference between climates. Land that is nearest to the equator has the most sun energy per unit area than places closer to the South and North poles. Differences in temperature can happen because different ecosystems have different characterestics of a physical nature. Pressure differences are caused by surface temperature differences. The air pressure is lowered when the air above a hot surface heats up, causing the air to expand. Wind is created when the resulting horizontal pressure gradient moves the air to low pressure from high pressure. These basic systems that are formed can show the behavior that emerges and more complicated systems are produced.

Terrestrial weather

Everyday phenomena of weather include snow, rain, wind, and fog. Far less frequent occuring phenomena include ice storms, earthquakes, hurricanes, and tornadoes. The lower part of the atmosphere is called the troposphere where all everyday weather phenomena are made. While some weather occurs in the stratosphere that might affect troposhere weather, the hows and whys are not well understood.

Because atmosphere is so connected, tiny changes in one part of the system have the ability to grow into much more serious effects throughout the system. This is why it is hard to predict weather successfully for more than a few days in advance. Weather forecasters who make these predictions are known as meteorologists. In theory, it is not possible to make usable daily predictions for longer than two weeks ahead of time. In a scientific theory known as the Chaos Theory, it states that even the tiniest variation in air motion can grow and change given time. Also known as the butterfly effect, this theory is based on a supposed change in the state of atmosphere much like the flapping of butterfly wings.


When science and technology are applied to make a prediction of the state of the atmosphere in the future, it is known as weather forecasting. Before scientific methods were implemented in weather forecating, there was a lot of folklore and mythology created to help explain different aspects of the weather. One example is the celebration of Groundhog’s Day which occurs near the end of winter in parts of the United States and Canada. It tells if spring is near or far by determining whether or not the groundhog sees his shadow. Nowadays, forecasts are made through the collection of data describing current atmospheric states and the utilization of mathematical equations in determining possible atmospheric changes in the future. Of course, due to the turbulent nature of weather, it is not possible to make perfect forecasts especially when the direct range of the forecast is increased by many days in the future or by distance covered.

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