Atmospheric pressure

Definition of Atmospheric Pressure

Atmospheric pressure, alternatively known as air pressure or barometric pressure, denotes the force applied by the weight of Earth's atmospheric envelope on a specific surface area. It plays a pivotal role in meteorology by shaping weather formations, dictating air circulation, and determining gas behaviors. Common units of atmospheric pressure measurement encompass pascals (Pa), millibars (mb), and inches of mercury (inHg).

How Atmospheric Pressure is Measured

Barometer: Barometers represent the primary instruments for atmospheric pressure measurement. Two prevalent types of barometers exist - mercury and aneroid. In mercury barometers, a mercury-filled column counterbalances atmospheric force, while aneroid barometers utilize a sealed, flexible metal chamber that contracts or expands due to air pressure changes.

Altimeter: Within contexts including aviation and mountaineering, altimeters often serve to estimate altitude according to atmospheric pressure. As altitude elevates, atmospheric pressure reduces, enabling the altimeter to deliver a rough elevation calculation.

Factors Influencing Atmospheric Pressure

Altitude: Altitude constitutes a primary determinant of atmospheric pressure. With increasing altitude, air molecule density declines, thereby reducing atmospheric pressure. Hence, mountainous locales typically exhibit lower air pressure compared to sea-level regions.

Temperature: Temperature influences atmospheric pressure as well. Warm air, being less dense, rises and incites a decrease in air pressure. In contrast, cold air, due to its higher density, descends and promotes an increase in air pressure.

Weather Systems: High and low-pressure systems fundamentally steer weather patterns. High-pressure systems, linked with descending air, clear skies, and tranquil weather, differ from low-pressure systems, correlated with ascending air, cloud genesis, and precipitation.

Atmospheric Pressure and Human Health

Pressure Changes: Swift alterations in atmospheric pressure, experienced during phenomena including air travel or mountain ascents or descents, can induce temporary discomfort and minor health concerns. Potential symptoms range from ear pain or issues equalizing middle ear pressure to mild altitude sickness.

Chronic Low Pressure: Sustained exposure to low atmospheric pressure, resulting from residing at elevated altitudes, can provoke physiological adaptations in the human body. Possible changes encompass red blood cell count augmentation to enhance oxygen transport capacity and modifications in respiratory functionality.

Atmospheric Pressure in Weather Forecasting

In weather prediction, atmospheric pressure information forms an integral component. Meteorologists scrutinize pressure patterns to locate and follow high and low-pressure systems, aiding in forecasting weather conditions and potential storms. Surveillance of atmospheric pressure changes can also serve as a precursor to severe weather events, including hurricanes and tornadoes.
Updated: Jun 1, 2023
Published by: Weather U.S. | About Us