Atmospheric pressure is the weight or force exerted by the atmosphere on a defined part of the Earth. Barometers are used to measure pressure, with mercury or water barometers measuring air pressure by pushing the material up a tube. Aneroid barometers use the contraction and expansion of a metal cell to measure pressure. Air pressure decreases as altitude increases, with sea level having the highest pressure. Meteorologists use barometers to predict changes in air pressure, which can help predict severe weather patterns.
Atmospheric pressure, also called atmospheric pressure or barometric pressure, is the amount of weight or force that the atmosphere exerts at any given moment on a defined part of the Earth. The primary means of measuring atmospheric pressure is by using an instrument called a barometer, which is the origin of the term barometric pressure. Mercury or water barometers consist of a hollow tube attached at one end to a container of mercury or water. The air pressure pushes the material up the tube, producing an air pressure measurement. Meteorologists often use an aneroid barometer, which uses the contraction and expansion of a metal cell to measure atmospheric pressure.
Because the amount of air in the Earth’s atmosphere decreases as altitude increases, a measurement of air pressure at sea level will be higher than one measured at a higher elevation and lower than one measured from a lower elevation. At sea level, which is zero elevation, the amount of air pressure is sufficient to raise the mercury level in a barometer by about 30 inches (76.2 cm). The increase in pressure on the mercury will cause it to rise approximately 1 inch (2.54 cm) for each additional 1,000 feet (304.8 m) of elevation. A high pressure area is defined as a measurement of air pressure above that at sea level, while low air pressure is a measurement below that at sea level.
An aneroid barometer is an electronic device that can also be used for measuring air pressure. Unlike the mercury barometer, aneroid barometers contain an airless metal chamber that expands or contracts as the air pressure changes. These pulses in the metal are converted into digital signals which provide an output reading of the air pressure. Aneroid barometers are often used in home weather forecasting devices, which use changes in air pressure combined with other atmospheric information.
Meteorologists use barometers to predict changes in the Earth’s air pressure. This information can be used to create maps of a particular country or region showing areas of high and low pressure, as well as areas where airflow is causing atmospheric changes. This data, combined with other information such as air temperature, wind speed and humidity, is the primary means of predicting thunderstorms, tornadoes and other severe weather patterns. A rapidly decreasing air pressure measurement can be a predictor of strong winds, because wind is created by air molecules continually moving from high-pressure to low-pressure areas in an attempt to equalize.
Protect your devices with Threat Protection by NordVPN
