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During these dark months the air high over the poles becomes much colder than the air over the Equator. This difference in temperature gives rise to extreme air pressure differences in the stratosphere which, when combined with the Coriolis effect, create the polar night jets, that race eastward at an altitude of about 48 kilometres (30 mi). [111]
This accelerated air can, and does, reach supersonic speeds, even though the airplane itself may be flying at a subsonic airspeed (Mach number < 1.0). At some extreme angles of attack, in some airplanes, the speed of the air over the top surface of the wing may be double the airplane's airspeed. It is, therefore, entirely possible to have both ...
Atmospheric air pressure is directly related to altitude, temperature, and composition. [1] In engineering, airflow is a measurement of the amount of air per unit of time that flows through a particular device. It can be described as a volumetric flow rate (volume of air per unit time) or a mass flow rate (mass of air per unit time).
The tropopause is a layer which separates two very different types of air. Beneath it, the air gets colder and the wind gets faster with height. Above it, the air warms and wind velocity decreases with height. These changes in temperature and velocity can produce fluctuation in the altitude of the tropopause, called gravity waves.
The rising air of the wave, which allows gliders to climb to great heights, can also result in high-altitude upset in jet aircraft trying to maintain level cruising flight in lee waves. Rising, descending or turbulent air, in or above the lee waves, can cause overspeed, stall or loss of control.
The effect of friction, between the air and the land, breaks the geostrophic balance. Friction slows the flow, lessening the effect of the Coriolis force. As a result, the pressure gradient force has a greater effect and the air still moves from high pressure to low pressure, though with great deflection.
The movement of air in the Walker circulation affects the loops on either side. Under normal circumstances, the weather behaves as expected. But every few years, the winters become unusually warm or unusually cold, or the frequency of hurricanes increases or decreases, and the pattern sets in for an indeterminate period.
2.2 High temperature effect. ... At an altitude of 104 km (65 mi), where the air is thinner, ... where a is the speed of the sound wave and v is the flow velocity.