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The thermal wind is the difference in the geostrophic wind between two levels in the atmosphere. It exists only in an atmosphere with horizontal temperature gradients. [5] The ageostrophic wind component is the difference between actual and geostrophic wind, which is responsible for air "filling up" cyclones over time. [6]
It is also referred as the geostrophic wind. [2] Pressure differences depend, in turn, on the average temperature in the air column. As the sun does not heat the Earth evenly, there is a temperature difference between the poles and the equator, creating air masses with more or less homogeneous temperature with latitude.
The wind speeds are greatest where temperature differences between air masses are greatest, and often exceed 92 km/h (50 kn; 57 mph). [24] Speeds of 400 km/h (220 kn; 250 mph) have been measured. [29] The jet stream moves from west to east bringing changes of weather. [30]
There are also links to be found between wind speed and wind direction, notably with the pressure gradient and terrain conditions. The Pressure gradient describes the difference in air pressure between two points in the atmosphere or on the surface of the Earth. It is vital to wind speed, because the greater the difference in pressure, the ...
Wind chill index values for a range of temperatures and wind speeds, from the standard wind chill formula for Environment Canada. Wind chill (popularly wind chill factor) is the sensation of cold produced by the wind for a given ambient air temperature on exposed skin as the air motion accelerates the rate of heat transfer from the body to the surrounding atmosphere.
The rising air creates a low pressure zone near the equator. As the air moves poleward, it cools, becomes denser, and descends at about the 30th parallel, creating a high-pressure area. The descended air then travels toward the equator along the surface, replacing the air that rose from the equatorial zone, closing the loop of the Hadley cell. [3]
Wind gradient is also a hazard for aircraft making steep turns near the ground. It is a particular problem for gliders which have a relatively long wingspan, which exposes them to a greater wind speed difference for a given bank angle. The different airspeed experienced by each wing tip can result in an aerodynamic stall on one wing, causing a ...
For example, if the wind is at 09015 that means the wind is currently from heading 090 degrees with a speed of 15 knots and the aircraft is taking-off from runway 24; having heading of 240. The pilot prefers the runway side with less than 90 difference from wind direction, in this case Runway 06; heading 060.