How to explain the late rain, Shuquan Veri and Ya 'an Tianlou with geographical knowledge?
2005- 12-3 1 reading times: 656 times.
"I have lived in Ya 'an all my life and have deep feelings for Yayu. All the year round, when it doesn't rain in Ya' an, you can count it with your fingers. " Mr. Zhang, who lives in the urban area of Ya 'an, told the author that it rained for 29 days on June 5,438+10/one year: "People were going to be moldy during that time."
Rainy days in Ya 'an have four characteristics. Guikang Peng, a senior engineer of Ya 'an Meteorological Observatory, has been studying the phenomenon of rain leakage in the sky. He introduced: "First, there are many rainy days. According to the statistics of meteorological observation data, there are 2 18 rainstorms and cloudy and foggy rainy days in Ya 'an in 365 days a year. Second, the rainfall is heavy. The average annual rainfall in Ya 'an is over 1.800mm, which is really rare in the mainland. Third, the precipitation hours are long, and the accumulated precipitation hours in the whole year are as high as 23 19 hours. "
Ya 'an is rainy, which has two remarkable characteristics. Mou Kequan, a senior engineer of Ya 'an Meteorological Observatory, told the author: First, it rained heavily at night. More than 70% of the rain in Ya 'an occurs at night. In many cases, the rain starts at night and disappears at dawn, and the night rain is mostly concentrated in autumn, especially between September and 10 every year. Followed by heavy rain. Rainstorms in Ya 'an generally occur in summer, with an average annual number of rainstorms of about 8 times, and the maximum number of rainstorms in a year reaches 15.
It is puzzling that with the change of climate and the deterioration of ecological environment, there is less and less rain in many places. Just when other places were crying for thirst, Ya 'an City, Sichuan Province, which is known as the rainy city, was overcast, rainy and the sky was leaking. Then, why does the rainy city "leak"?
-A legend.-The Goddess of Mending Heaven left a grudge?
Why does the rainy city leak water? Every foreign tourist who has been to Ya 'an will have doubts in his heart. "It's amazing to feel the rain in Ya 'an. I don't know why it always rains in this place. " A foreign tourist surnamed Li said with emotion.
Speaking of why it leaks rain, we heard a beautiful myth and legend in Ya 'an: In ancient times, the sky was broken by the black dragon, and the ancestor of mankind, Nu Wa, was refined into colored stones to make up the sky. When the sky was finished elsewhere, only Ya 'an was left, Nu Wa was exhausted. She barely lifted the last colored stone and flew over Ya 'an. After several efforts, I finally fell to the Ya 'an boundary due to overwork and vomited blood to death. Since then, Ya 'an has been shrouded in heavy rain, and Nu Wa has also turned into a mountain peak in the rainy city, watching with regret by the Qingyi River.
Whether this legend is credible or not, Ya 'an people's respect for Nu Wa, the ancestor of mankind, is obvious to all. Next to the Music Square in Ya 'an City, there stands a stone statue of the goddess of mending the sky: Nu Wa holds a stone in her hands, looking up at the sky, and she is about to spread her wings and fill the sky. "Although Nu Wa didn't mend the sky in Ya 'an, she died in tears to mend the sky, so Ya 'an people will always regard her as the patron saint of Rain City." An elderly Ya 'an citizen said.
-Uncover the loophole-
Answer 1: The leaking sky in rainy city is the result of the interaction of several air currents.
"The water leakage in Yucheng is actually caused by the special geographical environment in which Ya 'an is located. Guikang Peng, senior engineer of Ya 'an Meteorological Bureau, told us. Since the early 1990s, Guikang Peng and lasg experts have made a systematic study on "Rain City Leakage".
He said that to the west of Ya 'an is the Qinghai-Tibet Plateau, known as the roof of the world, and to the east is the Sichuan Basin, thousands of miles away. Ya 'an is located between these two completely different landforms, and is often influenced by the interaction between the warm and humid airflow flowing downward from the plateau and the basin. In addition, a large number of warm and humid air currents are carried by the westerly winds from the southern branch of the Indian Ocean and are often forced to move eastward around the plateau into Ya 'an. The interaction of these air currents leads to more rainy days, longer rainfall time and heavy rainfall in Ya 'an.
He pointed to a topographic map of China and showed it to us. It can be clearly seen from the map that Ya 'an lies between the plateau and the basin. Even a layman can imagine that once there is any trouble in the air flow over the plateau and basin, Ya 'an will encounter rain.
Answer 2: The leaking weather in rainy city is caused by Ya 'an trumpet-shaped terrain.
"There is another important reason for the leakage of rain in Yucheng, which is created by the unique geographical form of Ya 'an. Liu, director of the Ya 'an Meteorological Observatory, added that he has been engaged in forecasting for many years, and it is not difficult to find that Yucheng seems to be a "little daughter-in-law" who suffers indignities, and her personal freedom is completely controlled by her husband and in-laws: the tall and majestic Erlang Mountain in the west, the steep mountain in the northwest, the Big Xiangshan Mountain in the south and only one exit in the east.
This terrain is trumpet-shaped, and the warm and humid airflow from the east can only enter but not exit. At night, the cold air in the surrounding mountains sinks. Once the cold air meets the warm air, the wronged "little daughter-in-law" in Yucheng can only Lacrimosa-it rains intermittently, which is also the reason for the rainy night in Ya 'an.
Answer 3: Rain City Sky Leakage is the water vapor transported by the southerly air flow in the Pacific Ocean.
In addition, Liu also pointed out that the leak in Yucheng needs a lot of warm and humid water vapor. From the analysis of atmospheric circulation situation, the atmospheric circulation that transports water vapor to Yucheng includes Pacific subtropical high and southerly airflow. With their help, the sky in "Rain City" keeps leaking rain.
Answer 4: The most fundamental reason for leaking the sky in rainy cities is topography.
Judging from the explanations of two experts, "the most fundamental reason for the rainy city leaking the sky is the topographic factor, because there is not much rainfall in other areas adjacent to Ya' an, especially the two counties of Luding and Hanyuan on the side of Erlang Mountain and Daxiangling, which are very different from Ya' an." Liu He told us.
In order to confirm what the experts said, after the interview, we crossed Erlang Mountain along the Sichuan-Tibet Highway. As a result, we were surprised to find that the climate, landform, vegetation and soil on the east and west slopes are very different just across a mountain. At the foot of Dongpo Mountain, the vegetation on both sides of the highway is lush, and the virgin forest is lush and endless, but the weather is really pleasing, either raining or foggy. As soon as the car turned over the mountain pass and began to go downhill, it was another world: boundless blue sky, bright sunshine, flawless clouds and transparent and fresh air. Looking ahead, you can see icebergs and snow peaks towering into the sky. Looking down at the land at the foot, I saw the rugged yellow land desolate and bleak. The climate here is dry, the hot air is fierce, and the stream is cut off-who would have thought that it is only separated by a mountain, Dongpo and West.
Back in Ya 'an, we will invite meteorologists to analyze this phenomenon. According to Liu's analysis, this phenomenon is related to the complex and peculiar terrain conditions: Erlang Mountain is in an orderly north-south direction, making its eastern slope on the windward side, where a large number of warm and humid air currents condense into raindrops due to uplift, so there is more rain on the eastern slope; The west slope is blocked by a tall mountain, and the warm and humid airflow is almost lost when crossing. After crossing the mountain, the temperature will be too high, resulting in the evaporation of the remaining water vapor. Coupled with the terrain barrier around the western slope, the temperature is high and evaporation is strong, so it is difficult to form clouds into rain, so the climate around the western slope is dry and rainy. It seems that the rainy city is really caused by the unique geographical environment created by nature. But the geographical environment like Ya 'an is unique in the world, so the rainy city in the world can only belong to Ya 'an.
■ Ya 'an Three Musts
Ya 'an is famous for its "three wonders": Yayu, Yayu and Yayu. When foreigners come to Ya 'an, they must feel the three wonders of Ya 'an: elegant rain, elegant fish and elegant women.
"As far as causality is concerned, Yayu created Yayu and Yayu." Liu, director of Ya 'an Meteorological Observatory, explained that because of the rain, there are many rivers in Ya 'an, the water quality is very good and there is basically no pollution, so the fish grown in the rivers are delicious; Similarly, because of more rain, Ya 'an has less sunshine and humid air, which has a good protective effect on people's skin. Therefore, all elegant women are white and beautiful.
■ Link
The holes in the sky have created countless weather.
In the rainy city, because there are many leaks, many magical meteorological landscapes are created.
Old tree tears: In Taihu Temple in Yingjing County, Ya 'an, there is an old tree crying, which is equally puzzling: the summer is hot and the heat is unbearable. However, as long as people stand in front of that magical old tree with tears, the heat will disappear immediately and it will be extremely cool. According to a foreign tourist who has personally experienced the shade of an ancient tree, this ancient tree is about 15 meters high, with a trunk diameter of more than one meter and a total shade area of about 20 square meters. From a distance, there are lush trees and shade everywhere. Close up, the trees are towering, the branches are entangled, and the bark is rough as scales. What's even more amazing is that water droplets, large and small, will fall from time to time on the tree. When you come here in summer, you will feel cool and the summer heat will disappear completely. The hotter the weather, the more water drops there will be on the tree. The locals call this tree "an old tree that will cry".
According to the analysis of meteorologists, this is probably related to the climatic conditions around Taihu Temple: there are many rainy days and high humidity, and the ancient trees have been moistened by rain and dew for a long time, and sufficient water has naturally accumulated in the trunk. In rainy weather, due to the humidity saturation in the air, the moisture in ancient trees is "blocked" by external saturation and generally does not overflow; Once the weather clears up and the humidity in the air decreases, the water pressure in the ancient trees is greater than the external resistance, and the water will seep out. Of course, this "weeping" phenomenon of ancient trees has a lot to do with its rough bark and easy storage of water in the trunk.
Fish spray omen: In addition, there are mysterious meteorological landscapes caused by the leaking rain in the sky and "fish spray omen". In the Zhougong River in Ya 'an, whenever the weather gets worse and before the storm comes, there will be a kind of "grouper" dragged out of the hiding cave and scrambling to jump out of the water. When the fish jumps up, it looks like a cave for spraying fish. According to the local people, the phenomenon of "spraying fish" appeared relatively late, and there was usually strong wind and heavy rain. According to meteorologists, this phenomenon is caused by the change of atmospheric pressure: before the storm, the atmospheric pressure in the air decreased, resulting in insufficient oxygen in the water and very stuffy air. The fish in the cave had difficulty breathing, so they jumped out of the water to relieve boredom.
Author: Text/Jiang Yongyu Article Source: Science and Technology Daily (2005.438+02.29)