Barometric Pressure Readings

Studying the atmospheric pressure is one of the most important attribute of weather forecasting. Measuring the air pressure can help in analyzing the surface weather, and finding surface troughs or high pressure systems prevailing on the planet. One of the most popular instrument when it comes to measuring the atmospheric pressure is the barometer. Daily barometric pressure readings can help in determining the sudden changes in the weather, and predict the occurrence of the natural calamities associated with it.

Barometric Pressure Readings History
The credit for the invention of the barometer goes to Evangelista Torricelli, an Italian physicist, who achieved this feat in 1643. His experiment was by and large based on the observations of his teacher, Galileo Galilee. Torricelli questioned the popular belief that air did not have lateral weight. Instead, he proposed that air had weight, and it was this weight that held the column of air up. Further experiments by Torricelli revealed that the use of a liquid which was heavier than the water would make the task of measuring air pressure even easier. For this he chose mercury, which was 14 times heavier than water. As a result of this the size of the barometer reduced from 34 ft to 32 inches. Torricelli's experiments were perfected by Blaise Pascal and Pierre Petit in 1646. In fact, Blaise Pascal ascertained the fact that the air had lateral weight by proving that mercury barometer reading decreased as the altitude increased.

How to Read Barometric Pressure Readings?
A barometer tends to measure the peaks and valleys prevailing in the air pressure system, and helps in forecasting the weather patterns. While high pressure is a sign of a clear weather, low pressure is a sign of approaching rough weather. When the pressure is high, the density of the air tends to increase, which in turn, makes the air to fall and curbs cloud formation. On the other hand, when the pressure is low, the column of air tends to rise and results in formation of clouds. Basically, air moves from the high pressure area to the low pressure area. And thus, taking this low pressure formation in consideration can help in forecasting natural calamities like hurricanes. The atmospheric pressure in measured in terms of millibars (mb) or hectopascals (hPa). These measurements are shown on the weather map with the help of contour lines. The standard air pressure at 45° latitude, at the sea level is 1013 hPa. The barometer has to be adjusted to your local setting in order to get the local barometric pressure readings. In fact, a sudden drop in the current barometric pressure readings is a prediction of a stormy weather.

This was brief information about the barometric pressure readings, and how they help in weather forecasting. The next time you see a weather map flashing on your television screen, with all those contours, peaks and valleys, you will be able to understand the concept better. These contours on the weather map are basically the demarcations of the pressure system, and the area wherein they come together, i.e. the center of the pressure system is the low pressure area. The fact that the air moves from a high pressure area to a low pressure area means that the low pressure area acts as a trigger factor for a storm formation.