Why is Lushan foggy?

There are two basic conditions for the formation of clouds: one is that the water vapor condition is good, and the other is that the underlying surface temperature is relatively low (low means compared with the dew point temperature). When the water vapor condition is ripe and the underlying surface temperature is close to or equal to the dew point temperature (it can be replaced by the dew point temperature at 1.5 meters), dew is very easy to form. It may not be surprising that "my clothes are exposed" in the morning or foggy days, but it is obvious that it is early to plant beans in the evening, and beans grow at the turn of spring and summer and mature in midsummer. "Moon lotus hoes home" means that he just came back from the bean field at that time, and the time should not be too late. At the turn of spring and summer, it is about eight o'clock in the evening according to the current Beijing time. Generally, the temperature in Jiangnan water town will gradually drop below the dew point after summer night 10, but in Tao Yuanming's idyllic residence in Lushan Mountain, the water vapor will condense into dew at 8 pm, indicating that Lushan Mountain is rich in water vapor, and the climate in mountainous areas is different from that in plain areas. Lushan Mountain is bordered by the Yangtze River in the north, Poyang Lake in the southeast and hilly and mountainous areas in the southwest. The southeast monsoon, which began to prevail in southeast China in early summer, brought a lot of water vapor to Lushan Mountain. The rapid heat dissipation on the mountain, the large temperature difference between day and night, and the rapid drop of the corresponding temperature at night were the geographical conditions for the early formation of dew on Lushan Mountain.

In addition, the formation of dew should have certain weather conditions. Generally, the atmosphere is stable, the wind is small, the sky is clear and partly cloudy, the ground heat can dissipate quickly, and the temperature drops. Such weather will be conducive to the formation of dew, and water vapor will form dew when it meets cold ground or objects. "Bring the lotus home with the moon" means that it is a good weather with sparse stars in a month, which is conducive to the formation of dew. It can be seen that a fresh and natural poem not only contains the description of natural phenomena, but also conforms to certain scientific laws. The value of ancient poetry to the study of ancient climate can be seen.

The second is the real cloud. Rich water vapor has created unparalleled beauty of clouds for Lushan Mountain. Now, many tourists come from Lushan Mountain in the name of clouds, eager to see the magnificent scenery. The fog in Lushan Mountain is erratic and unpredictable. Sometimes it rises from Ran Ran in the valley and suddenly flies lightly in mid-air. One moment it was dark and churning, and the other moment it suddenly rose as thin as a veil. The fog is psychedelic, and the tall and steep peaks add mystery to the scenery of Lushan Mountain. Su Dongpo, a famous poet in the Song Dynasty, sent a message in the poem Tixilinbi:

Ignorance of the true face of Lushan Mountain is largely related to the cloud. The fog in Lushan Mountain looks like a cloud at the foot of the mountain, and from a distance it looks like a snow-white felt hat buckled on the top of the mountain or a gauze wrapped around the waist. When people look around at the fog on the mountain, not only the distant peaks and rocks are hidden in the fog, but they are often in dense fog. The sea of clouds in Lushan Mountain is even more varied and praised by people. For example, Zhang Weiping, a writer in the Qing Dynasty, wrote that the clouds on Lushan Mountain are "like snow, soft as cotton, light as silver, wide as the sea, thin as wadding, thick as felt, moving or smoking, still or waves." This shows that the beautiful scenery on the mountain is really pleasing to the eye Bao Zhao's "atmospheric fog bears the stars, and the pool river is full of holes" lets us know that the fog on Lushan Mountain rises early and has a wide range. Qian Yu even "only suspects the cloud cave", thinking that there are cloud sources on Lushan Mountain, which makes people have to ask, "Are the clouds on Lushan Mountain really that rich?" According to the current records, the average foggy day in Lushan Mountain is 19 1 day. It is foggy from May to June, and there are 20 foggy days in July, 13 foggy days.