What kind of weather does the weather factory mean?

High-altitude jet is called "weather factory" because it can produce all kinds of weather phenomena that endanger flight safety.

High-altitude jet is a strong and narrow airflow around the earth. It is concentrated in the upper troposphere or stratosphere, and its central axis is quasi-horizontal, with strong horizontal shear and vertical shear, and has one or more wind speed maxima, which is called jet stream area.

Usually, the rapids are thousands of kilometers long, hundreds of kilometers wide and several kilometers thick, with a vertical wind shear of 5- 10 m/s and a horizontal shear of 5m/ s every 100 kilometers. The lower limit of wind speed on the jet axis is 30m/s.

Statistics show that sandstorms and high-altitude jet always appear together, and sandstorms caused by high-altitude jet can be divided into two types, single jet type and double jet type. Large-scale strong sandstorms are often accompanied by double rapids. It is also found that there are jet variations in some double jets, which play an important role in the occurrence and development of sandstorms.

Tao et al. (1987) pointed out that the 200 HPA westerly jet is an important system that affects the weather and climate in East Asia. Matsumoto et al. (197 1) believe that the rainstorm mainly occurs about 300 kilometers south of the upper jet axis. Whitney( 1977) studied the relationship between five local storms and subtropical jet in the spring of 1975.

It is considered that severe thunderstorms occur on the south side of the upper jet axis. Chen (1982) studied the instability of gravity inertial wave and the relationship between low-level jet and rainstorm, and thought that if the conditions of gravity inertial wave instability were met at the entrance of upper-level jet, a strong thermal direct circulation would be excited at the entrance of upper-level jet.