Let's talk about it Why does the wind in Maoxian come on time?

Maoxian County is located in the alpine valley in the northern section of Hengduan Mountain System on the eastern edge of Qinghai-Tibet Plateau, and in the middle of the upper reaches of Minjiang River, an important tributary of the Yangtze River. It is the center of the arid valley area in western Sichuan. The territory of towering mountains, overlapping peaks, deep canyons, cliffs. There are Minshan Mountain in the north, Longmen Mountain in the south and Qionglai Mountain in the west, which is known as the "dangerous peak inserted into the Han Valley". The terrain is high in the northwest and low in the southeast, and the mountains are about 4000 meters above sea level. Wannian Xuefeng, the highest peak in the west, is 5230 meters above sea level, and the bottom of the lower reaches of Tumen River in the east is 890 meters above sea level, which is the lowest point in the country. The Minjiang River runs through the whole territory from north to south. Heishui River, Chibusu River and Songping River join the Minjiang River at the mouth of Daxiang River and Diexi Town respectively. Tumen River runs through Tumen area from west to east and flows into Fujiang River system. The climate is dry and windy, Leng Xia is cool in winter, the temperature difference between day and night is large, the regional difference is great, and the ecological environment is very fragile.

Why does the noon wind in Maoxian sometimes blow fast and strongly, but sometimes it is lazy and weak and disappears? This is completely dominated by the objective laws of contradictory movements such as high and low air pressure and cold and warm in the atmosphere.

Let's know about the meteorological conditions in Maoxian: the annual average temperature in Maoxian is 1 1.2℃, the average temperature in July is 20.9℃, the lowest temperature is-1 1.6℃ and the highest temperature is 32℃. The average sunshine hours are 1557.438+0 hours. The annual precipitation is 490.7mm, and the average evaporation is1375.7mm. The frost-free period is 2 15.8 days. The temperature in the valley is very different from that in the mountains. In spring, the snow and ice in the mountains have not melted, and the valley is full of flowers.

People don't know why it is windy at noon every day. There is an idiom called groundless. There are reasons for news and legends. However, the dry valleys in Maoxian county are prone to wind, and there are too many holes in the dry valleys. Why the wind started at noon is not as simple as the legendary story. This is entirely caused by climate change.

Every place on the earth is absorbing the heat of the sun, but because every part of the ground is heated unevenly and the air temperature rises to different degrees, the warm air expands lighter and then rises; Cold air cools and becomes heavier and then falls, and cold and warm air flows to form wind. Because this area is in the transition zone from the first step to the second step in China, the relative height difference of terrain is as high as 3000 meters, and the vertical belt spectrum of vegetation and climate is obvious. It is a sensitive area of mountain environment change in China, and a unique mountain type area in China and even the world.

The sun is dizzy in the middle of the night, it rains in the middle of the night, and the wind is strong at noon. Halo is an internal infrared blue halo formed by cirrostratus reflection or refraction of sunlight or moonlight through ice crystals. Cirrostratus usually appears in front of low pressure. If the low pressure approaches, the clouds will become: cirrostratus-upper clouds-nimbostratus, and then it will rain. And because the wind is strong in the relatively strong low-pressure area, the appearance of this cloud indicates that there will be rainy weather. Maoxian, a unique mountainous area, has plenty of sunshine and a large temperature difference between day and night. It is very easy to get dizzy at night, so there is a midday wind. In addition, the thicker the cirrostratus at night, the less you can see the stars in the lunar halo, indicating that the low pressure is approaching. So there is a saying that the wind in the sun is a flail, the rain at night is a flail, and there are no stars in the flail.

(Look at a statement found in the search. )