What is the cause of the snow disaster on the Qinghai-Tibet Plateau?

In meteorological observation, there is a special weather phenomenon term to describe snowstorm-snowstorm.

It is the strong wind that carries snowflakes and even affects visibility.

Therefore, it is necessary to analyze the causes of two weather phenomena on the plateau: gale and blizzard.

The simple and smooth explanation is as follows.

First, the causes of strong winds.

The Qinghai-Tibet Plateau has always been one of the windy areas in China, and the number of windy days is much more than that in the plains of the same latitude in China. The annual gale (the wind force is greater than17m, and the level of wind is 7) even exceeds150th day, and the maximum wind speed can exceed 30m (1 1 level), which is a strong tropical storm. 12 The wind force is typhoon level).

The cause of gale is related to the topography and rapids on the plateau. The trend of Kunlun Mountain, Himalayan Mountain and Gangdise Mountain on the plateau is generally consistent with that of westerly jet at high altitude. When the westerly jet is strong in winter and spring, the plateau has strong thermal effect, which easily leads to atmospheric instability and strong convection between the upper and lower air. The momentum carried by westerly jet is transported downward with air convection, which intensifies the wind speed near the plateau and is easy to form strong winds. In addition, the mountain valley wind and glacier wind make the wind direction in the plateau more complicated.

Second, blizzard.

There are many causes of blizzard.

The westerly trough (single trough and superimposed trough) on the Qinghai-Tibet Plateau belongs to large topography. When the low-level airflow (this is the low-level airflow, and the westerly jet mentioned above is the high-level airflow) comes, there is little confrontation (of course, some), and most of them can only bypass the Qinghai-Tibet Plateau. Therefore, the south branch trough will be formed when the airflow goes south, and the high pressure ridge will be formed in Xinjiang when it goes north along Tianshan Mountain. Of course, this is far-reaching.