Why are the tail clouds different in length in different weather?

Aircraft wake means that when people often see a jet plane flying high in the clear sky, one or several long "white smoke" will appear behind the fuselage. In fact, this is not the smoke produced by a jet plane, but a special cloud system formed by the condensation of water vapor after the exhaust gas from the plane is mixed with the surrounding air, which is called aircraft wake in aviation flight and aviation meteorology.

The aircraft consumes a lot of fuel when flying, and the generated water vapor and some heat are discharged from the aircraft with the exhaust gas, enter the atmosphere, and quickly mix with the surrounding air to form a condensation trail. Its formation process is different from dew on the ground, frost and clouds in the air. The exhaust gas from high-altitude aircraft is mixed with ambient air, and the saturation of this mixed gas depends on the net effect of heat and water vapor increment. When the humidification effect is dominant and exceeds the given critical value, the condensation trail will be formed; When the thermal effect is dominant, condensation will not occur and there will be no condensation traces. Because the heating and humidification of waste gas is certain, whether condensation will occur in this mixed gas depends on the temperature, humidity and atmospheric pressure of the ambient air itself. In short, when the ambient air temperature is high, it is not conducive to the formation of condensation trails. Only when the ambient temperature is quite low (usually below -40℃) can the condensation wake of the aircraft appear. According to relevant data, at present, the temperature of aircraft tail outflow is mostly -4 1℃ ~-60℃, accounting for about 86% of aircraft wake. If the temperature is higher than -40℃ or lower than -60℃, the aircraft wake rarely appears.

A special kind of cloud, which is formed by mixing and condensing the exhaust gas from the engine and the surrounding air during the flight of an airplane. It usually occurs in the air layer where the temperature is below -40 degrees and there are suitable humidity conditions. Aircraft wake has no influence on flight, but its exposure has certain influence on aviation operations.

Aircraft wake cloud does not exist for a long time, and usually disappears quickly, but it can exist for more than 1 hour under favorable conditions, and can expand into a wider cloud layer. Not all aircraft can produce this kind of wake cloud. Jet aircraft can only produce wake cloud when they fly in the air layer below -20 degrees Celsius, the air humidity is close to or saturated, and the atmosphere is relatively stable. When performing aerobatics in flight, smoke is composed of many colors, forming beautiful patterns. In order to pursue performance, this kind of smoke generator is specially installed on the plane, which makes the combustion products burn incompletely, thus producing traces similar to smoke.

Therefore, in different weather, the tail cloud of the aircraft will be different.