On winter days, when you turn on the radio, you often hear weather forecasts from meteorological radio: A piece of cold air from the north is flowing south. The temperature in the city will gradually drop. There are times when a cold wind warns: a cold air intensifies in the South, and the temperature will drop sharply. It’s all cold air flowing from the north to the South. Why is it so different when it goes South?
The overhead airflow explains this. The cold air originates from the polar region and the center of the continent. These cold air currents are concentrated in the lower layers of the atmosphere, and when the cold air mass is formed, it is controlled by the air currents above. The phenomenon of overhead air forces cold air toward the ground called overhead airflow.
At high and medium latitudes, the West winds bring strong sea air. The West wind is not caused by direct blowing from the West to the East, but the waveform from the West, sometimes the Northwest direction, sometimes the Southwest direction. The cold underground air mass is normally under the Northwest gas flow behind the West wind layer, following the West wind waveform. As a result, the cold underground air has shifted to the East and the South simultaneously. The amplitude of fluctuation in the South and North of the West wind waves is small and large; the wavelength is not the same.
Meanwhile, the travel speed of West wind waves and wavelengths are inversely proportional to each other; short waves run very fast, long waves run slowly. As a result, the cold air mass below the ground cannot accumulate to strengthen under the short wave situation. It is changed by the northwest wind airflow of the low-pressure area, so the cold air mass can only move sporadically small streams.
Due to the high wave vibration’s small amplitude, the force of the cold air mass below the ground is displaced, and only a few parts can spread southward. Therefore, the phenomenon of hypothermia is not too intense. When the high west wind appears, long waves, but long waves move very slowly, so the cold air below the ground has more time to continuously cool, and at the same time makes a lot of cold air gather together place, creating a great cold air.
Then, under the influence of high-scale Northwest high gas flow, much cold gas was formed and moved straight in and moved south. So when the air is cold South, it can create a strong northeast monsoon, causing the air temperature below ground to drop, creating a strong cold wind. In the overhead west-west gas current, the long waves and short waves gradually adjust, sometimes appear as short-wave forms, sometimes adjust into long-wave forms. Thus, the cold air mass southward also follows small streams, but sometimes it is strong winds, creating a damaging cold wave.