The vapour cone effect is caused by pressure differences around the aircraft. A sudden drop in pressure associated with high speed allows water vapour, which is normally invisible, to condense as fog.
蒸汽锥效应是由于战斗机周围的压力差所导致的，高速飞行时压力的陡然降低会使不可见的水蒸气凝结成雾气。
2
Australia's Bureau of Meteorology says the fog was caused by two days of onshore winds and highpressure over the city.
澳大利亚气象局说大雾是由悉尼城市上面连续两天的陆上风和高压引起的。
3
The warm high ridge at the middle and low troposphere and the lower pressure of the ground all provide the good circulation background of this heavy fog.