Isobar, lines drawn on maps and maps that may look like those for finding a treasure by getting closer and closer to the goal. They are precious, but for quite another reason. They help us understand what happens in the atmosphere and what the weather will be in the near future. And not only that ... after understanding how they are traced, maps and weather forecasts they will have a deeper meaning for us.
In meteorology isobars are ideal lines that join points with equal atmospheric pressure at sea level or at a certain elevation. We find them on the weather maps, always, certainly not on the maps we use to trace the way to go on a journey. I am one tool for "technicians" and not immediately useful for those who want to consult a map to get to their destination.
Isobar and weather
In meteorology, these lines they are used to establish and clearly define the areas of high or low pressure all over the globe. The first are called anticyclones, the second cyclones or even depressions, saccades. Observing the arrangement of the isobars high pressure promontories can be identified in a certain area of variable dimensions, wind direction and other consequent phenomena.
Once we recognize the high and low pressure areas, for example, we know that the winds blow parallel to these lines that delimit them with a slight inclination tending from anticyclonic to cyclonic zones.
As for the intensity, it grows gradually the isobars are close together between them because this means that the baric gradient is greater, i.e. that the pressure varies faster moving in space in that specific area high density of isobars.
Usually the areas where blood pressure is high it is over 1013 millibars, those in which it is low is below 1013 millibars, in the former there is generally good weather, in the latter bad weather.
In addition to lines, isobars, there are also le transformations. We move from meteorology to thermodynamics and we talk about isobar transformation when we want to describe the change of state carried out by a physical system in which the pressure remains constant.
Returning to the lines that describe the atmospheric pressure, it should be noted that, alone, they are not able to provide us with the tools to develop one reliable weather forecast. This is true both at national and European level.
If in general high pressure brings good weather and low pressure bad weather, this doesn't always happen. For example, in winter with high pressure you can also see foggy days and gray skies.
In Italy, moreover, there is a particularly varied territory, which sees the presence of many reliefs and plains, plateaus and promontories on a particularly warm closed sea: therefore it is not so easy to associate a certain atmospheric time with a pressure value.
A meteorologist who works for one weather forecast for Italy it must absolutely take into account the conformation of the ground, the pressure at ground level and many other parameters.
In Europe the same argument applies to theItaly even if not all the countries of the continent have the characteristics of ours, so "crumpled" and jagged.
In winter, in Europe, it dominates a large area of low pressure which brings a cold climate, especially in the internal part of the territory, with snowfalls that, in central-northern countries, also reach the plains while in those in the south, including Italy, the climate even with low pressure is the same milder even cloudy.
Though reliable weather forecasts cannot be made, only with isobars, looking at how they are arranged, you can guess, for example, how the wind turns. In theNorthern hemisphere rotates clockwise around high pressures and counterclockwise around low pressures, the very close isobars provide for a higher wind speed, a speed that is measured with the anemometer.
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