What is this in meteorology?
Isobar is a line of connecting points of the same atmospheric pressure on the weather. The word comes from the Greek words isos - equal - and baros - weight. By rendering isobarres at intervals based on pressure reading, areas with high and low pressure can be shown on the map, as well as hills and valleys on the landscape outline map. When studying isobars on the map, meteorologists can predict whether the weather will be clear or cloudy, wind strength and directions and - with regard to width and seasons - temperatures in a wide area. The air pressure decreases with altitude, so that the values are adjusted to sea levels to allow changes in altitude. In the US, pressure deduction is usually performed every hour and is usually in 4 millbarovy (MB) intervals using 1000 MB pressure as a base. From a set of air pressure deductions taken at the same time at various places in the area, the isobars can be brought by an estimate where the pressure would have the appropriate value.
For example, if the meteorological station reports a pressure of 1002 MB and other stations report several miles to the north 1006 MB, it can be estimated that the isobar 1004 would pass between them. On the isobar map, the isobars will be marked with the pressure values they represent, such as 996 MB, 1000 MB, 1004 MB, etc. The map also displays the individual values at different stations.
From the Isobar map, meteorologists can determine the probable weather in the next few days. Low -pressure areas, known as cyclones, elements into the air that rises in the center and is generally associated with cloud -clotting. The high -pressure areas, known as anticyclones, are associated with decreasing, discharge air and usually bring dry, clear weather.
windy flows from higher pressure areas to lower pressure areas. Isobars on the map show pressure gradients. If the isobars are far apart, it reflects it as a fine pressure gradient and light winds. If the isobars are close together, indicateIt is a steep gradient. The steeper the pressure gradient, the higher the wind speed.
pressure gradients are steeper surrounding areas of low pressure than around high pressure areas. If the isobar map is displayed as a landscape, high -pressure areas would look like gently sloping hills and low -pressure areas such as steep depression. In some areas, low -pressure areas are actually called.
If friction is ignored, the wind speed is determined by the force of the pressure gradient (PGF). This can be calculated as a result of high -pressure value minus low -pressure value, divided by distance, and is usually expressed as mliBary per kilometer (MB/km). For example, if the isobar map has a pressure drop from 1008 MB to 996 MB at a distance of about 12 miles (20 km), the pressure gradient is 12 MB/20 km, which is equal to 0.12 MB/km. This is quite a steep pressure gradient, so for this area it would predict strong winds.
wind direction is influenced not only by the orientation of the pressure gradient but also by CoriolIs Is Isa, which is the result of the country's rotation. In the northern hemisphere, this causes the winds around the low -pressure area to rotate counterclockwise and the people around the high -pressure area rotate clockwise. The opposite is true in the southern hemisphere. The amount of deflection due to Coriolis force is larger towards the poles and is also proportional to wind speed.
Ignoring friction, PGF and Coriolis power can be equal, resulting in winds that flow through paragraphs to isobars. These are known as geostrophic winds and can occur high above the ground where friction is not important. On the surface, however, the friction slows down the wind, reduces the effect of coriolis and winds tends to cross isobars, spiral inwards towards cyclones and out of anticyclons, clockwise or counterclockwise according to the hemisphere.