Introduce a natural phenomenon and use at least one explanation method.

Typhoon and hurricane are both a kind of wind, but they happen in different places and have different names. The typhoon is in the western part of the North Pacific Ocean, west of the international date, including the South China Sea; Tropical cyclones in the Atlantic Ocean or the eastern North Pacific Ocean are called hurricanes, which means hurricanes in the United States and typhoons in the Philippines, China and Japan. Typhoon is a strong tropical cyclone generated on the surface of tropical ocean. Typhoons are often accompanied by strong winds and heavy rains. The wind rotates counterclockwise. Isobars and isotherms are approximately a set of concentric circles. The central air pressure is the lowest and the temperature is the highest.

(2) A mirage

Mirage is an optical phenomenon in which light is constantly refracted and totally reflected in air with uneven refractive index under sunny, windless or breezy conditions. Due to the uneven change of air refractive index, the image of the object is distorted, and the disturbance of the breeze makes the fairyland disappear, which is even more mysterious.

The air near the sea surface has a high refractive index due to the low temperature of seawater and humid water vapor, while the air above it has a high temperature due to sunlight. That is to say, the refractive index of the air layer above the sea surface gradually decreases from bottom to top with the height. When light passes through the air layer, it bends downward through constant refraction.

The distant scenery on the sea is hidden below the horizon, so people can't see it directly. When the light emitted into the air from these scenes continuously bends to the ground and reaches the human eye, people will look against the light and see a strange sight that they have never seen before, just like the fairy pavilion flying in the air. (3) Debris flow

Debris flow is a special torrent containing a lot of mud, sand and stones, which is stimulated by heavy rain, water, snow and valley melt water. Often manifested as a sudden outbreak, turbid liquid pushes forward and backward along the steep ravine, rushing down, the ground shakes and the valley vibrates. In a short time, a large number of mud, sand and stones were washed out of the ditch, and after continuous refraction, they bent down and crossed the wide accumulation area.