The Taklamakan Desert, China's largest desert, has recently suffered a rare heavy snowfall, which has attracted many people's attention. What's going on? In the desert of our country, it can still rain? Is it because the northwest is wet? Do you want to change Gangnam to Biansai? Many people are a little surprised, isn't the chance of winter great? How can it be so cold? This is a valuable question.
Taklamakan is the 10th largest desert in the world and the third fastest desert in the world, covering an area of 330,000 square kilometres, four times the size of the United Kingdom. The region is located in the middle of the Tarim Basin in Xinjiang, with an annual rainfall of less than 100 mm, less than 4 mm, and an annual evaporation of 2500-3400 mm.
It stands to reason that there will never be snow here, but the Taklamakan Desert has snowed more than once. Since the beginning of 2021, there have been several snowfalls in this area. Why is this happening?
In fact, this is only possible because the conditions for snow are already in place here. There are two reasons for this snowfall, one is the high humidity and the other is the low temperature. And both of these can happen in the winter of Taklamakan .
First of all, although the Taklamakan Desert is an arid region, there are still many water sources around, such as the Tarim River, the Kumtag River, the Peacock River, etc., all of which come from mountains such as the Tianshan Mountains and the Kunlun Mountains, so there is also a lot of water here. When winter arrives, a strong blast of cold air blows from the south, bringing moisture into the desert, and under the right conditions, rain can be generated.
Secondly, the winters in the Taklamakan Desert are very cold, with an average annual temperature of around -4 and as low as -20, which is low enough for the air in the air to condense snow. In addition, because the albedo on the surface of the desert is high, the snow does not melt even during the day, but on the contrary, the snow becomes thicker.
To sum up, there is nothing surprising about snow in the desert, because this is only the case in places with high humidity and low temperatures. Therefore, instead of seeing heavy snow as a miracle, it is better to think of it as an ordinary natural phenomenon.
Seeing this scene, many people associate this scene with the weather in the northwest. Northwest China is the main region of agriculture and animal husbandry, and it is also the main ecological barrier of the country, and its climate change is directly related to the country's economic and social development. So, has the weather really changed in the Northwest of the United States? Is there more moisture? Will it become Gangnam?
In fact, climate change in the north-west of our country is a very complex subject, and we cannot put it together as a whole. From a long-term perspective, the climate of northwest China has indeed undergone "warm humidification", with rising temperatures and increased rainfall, and the reasons for this are closely related to climate change. However, as far as recent changes are concerned, the weather conditions in the northwest of China are still relatively complicated, and there are still some dry and snowy phenomena in some areas, the reasons for which largely depend on the monsoon, high pressure, cold air, etc. in China.
First, from the perspective of "warming and humidification", the climate change in the northwest of China is analyzed. Judging from the meteorological data, there have been signs of rising temperatures in northwest China in the past decade, with winter being the most obvious. In addition, the annual precipitation in the northwest of our country is also showing signs of rising, especially in summer, and the rate of increase is even faster. Climate warming is an important contributor to climate change.
Climate warming is caused by the anthropogenic release of a large amount of carbon dioxide, which affects the absorption and reflection of total solar radiation by the atmosphere, thereby causing the average temperature of the surface and atmosphere to rise. Climate change has important implications for climate change on a global scale, but varies from region to region and from season to season. For the Northwest United States, the consequences of climate change are as follows:
In the context of climate change, the increase of evapotranspiration on the land surface increases the concentration of moisture in the air, which increases the probability of rainfall. Under the background of climate change, the thermodynamic processes of the Tibetan Plateau in the northwest of China are more intense, which promotes the more active East Asian monsoon system, which prompts the rainfall area in the northwest of China to move northward, thereby increasing the precipitation and area in China. Due to climate change, the westerly wind zone in the northwest of our country has shifted northward, weakening the impact on the region, thereby increasing the temperature in our country and reducing the likelihood of snow cover.
Second, we will examine the changes in the north-west of our country. Although the weather in the northwest of China tends to be "warm and humid", this does not mean that the whole region is warm and humid, let alone that there is no precipitation or drought in the whole region. However, the weather conditions in the northwestern part of the country are complex and varied, with severe drought and heavy snowfall in addition to precipitation.
The monsoon is a type of wind that changes direction with the seasons and is caused by the rotation of the earth and the uneven warming of the surface. The East Asian monsoon and the South Asian monsoon are two significant characteristics of Northwest China, among which the monsoon system in China plays a significant role in climate change in China.
The East Asian monsoon blows from the Pacific Ocean to Asia in the summer, and from Asia to the Pacific in the winter. When the East Asian monsoon is strengthened, the water vapor and rainfall increase, while the weakening of the East Asian monsoon causes less water vapor and precipitation. The intensity of the East Asian monsoon is mainly affected by a combination of Pacific SST, El Niño, La Niña and other factors.
The South Asian monsoon blows from the Indian Ocean to Asia in the summer, and from the Asian continent to the Indian Ocean in the winter. The influence of the South Asian monsoon on Northwest China is as follows: the South Asian monsoon strengthens and the precipitation increases, and the South Asian summer monsoon weakens and the precipitation decreases. A variety of factors, such as the Indian Ocean SST, the Indian Ocean Dipole, and the Western Pacific Warm Pool, work together to influence the intensity of the South Asian summer monsoon.
When the air pressure is higher than the environment, the air pressure is high, the air pressure is generally a stable gas, and the boundary of the high air pressure is a moving air. The Qinghai-Tibet Plateau plays an important role in China's climate in spring and autumn, and its location in the northwest hinders the input of water and rain, causing drought. To the east, it favors the input of water vapor and rainfall, resulting in greater humidity. The Siberian high, the Mongolian high and the subtropical high have a certain control effect on the distribution of high pressure in this region.
Cold air is generally transported from the cold air in the north of China, and its climatic effect on China is manifested in winter: as the cold air moves to the south, it will produce cooling and snowfall, and if it does not move, it will lead to a long period of low temperature and snow. During this period, due to the presence of westerly winds, polar vortices, and resistance heights, the cold air in the region moves southward or is retained.
In general, the summer monsoon, high pressure, cold air and other factors in Northwest China jointly drive the changes of summer precipitation patterns in Northwest China, which are regulated by a wide range of climate systems such as global warming, ocean circulation, and atmospheric circulation. Therefore, the weather in the northwest of our country is not exactly the same, sometimes dry, sometimes snowy, sometimes warm and humid, sometimes cold.