Õhusurvet

Õhusurvet, also known as air pressure, is the force exerted by the weight of air in the Earth's atmosphere on a given surface. It is a fundamental concept in meteorology and plays a crucial role in weather patterns. Atmospheric pressure is highest at sea level and decreases with increasing altitude because there is less air above to exert pressure. Standard atmospheric pressure at sea level is defined as 101,325 pascals (Pa), or approximately 1 atmosphere (atm).

Air pressure is not uniform across the globe or even within a specific region. Variations in temperature and humidity cause differences in air density, leading to areas of high and low pressure. High-pressure systems are generally associated with stable, clear weather, while low-pressure systems often bring clouds, precipitation, and storms. The movement of air from areas of high pressure to areas of low pressure creates wind.

Meteorologists use barometers to measure air pressure. These instruments can be mercury barometers or aneroid barometers. Understanding air pressure is essential for forecasting weather, as it is a key indicator of atmospheric conditions. Changes in air pressure can signal approaching weather systems. For example, a rapid drop in pressure often suggests an approaching storm.