Barometric pressure refers to the weight of air that presses on the earth. Barometric pressure is also referred to as air pressure. When the barometric pressure is low, it is an indication of rising weight of overlying air and high barometric pressure implies reducing weight of overlying air. Barometric pressure has a significant effect on weather conditions. It has an effect on amount of gas that dissolves in water. Under high pressure, a lot of gas can be dissolved in water compared to when there is low pressure. For example, a lot of oxygen dissolves in at sea when the altitude is high. This is because more overlying pressure tends to force gas to dissolve. A decrease in the overlying air causes a release of gas from a solution. A popular example to illustrate this is when a person opens a beverage that is carbonated. High levels of barometric pressure are necessary for supporting favorable, clear, and sunny weather conditions. On the other hand, low barometric pressure encourages cloudy, rainy weather conditions. For a long time, barometric pressure has been used to forecast the weather conditions. Barometric pressure variances across big inland lakes generate changes that have an effect on water levels in the lake and its adjoining estuaries.
Measuring Barometric Pressure
Generally, barometric pressure is measured in millibars, which is basically inches of mercury. Traditionally, pressure was measured using a barometer which was first developed in 1644. A barometer has a glass tube that is open on one end and closed on the other end. An inch of mercury is equal to 33.9 millibars. When the air pressure rises, it pushes the mercury column up the barometer. Essentially, millibars provide a direct measure of atmospheric pressure. Currently, pressure is measured in SWMP taken using a more accurate and modern device known as capacitative pressure sensor.