Recently, CCTV News released the news that there are many lakes in the Taklamakan Desert in Xinjiang. As a dry desert all year round, where do these lakes come from? Is it true that "Loulan Oasis" will reappear as public opinion has speculated? Why are "extreme weather events" in the Taklamakan Desert so frequently searched?
Recently, CCTV News released the news that there are many lakes in the Taklamakan Desert in Xinjiang. In the video, the yellow sand and clear water of the Taklamakan Desert complement each other, shining brightly under the sunlight, and the scene is very spectacular. After the video was released, discussions on the topic of "Many lakes appear in the Taklamakan Desert in Xinjiang" rushed into the hot search, and some people put forward the argument that "the climate of the Han and Tang Dynasties and even the Loulan Oasis will reappear."
As a dry desert all year round, where do these lakes come from? Is it true that "Loulan Oasis" will reappear as public opinion has speculated?
Where do the lakes in the desert come from? The Taklamakan Desert,
located in the center of the Tarim Basin in southern Xinjiang, is the largest desert in China and the tenth largest desert in the world. According to public data, the Taklamakan Desert is about 1,000 kilometers long from east to west, 400 kilometers wide from north to south, and covers an area of about 330,000 square kilometers.
The average annual precipitation in the Taklamakan Desert does not exceed 100 mm, the lowest is only 4 to 5 mm, while the average evaporation is as high as 2500 to 3400 mm. Why do lakes exist in such an arid environment? Where are these lakes scattered?
After investigation, it is known that the beautiful photos of the "desert lake" posted on the Internet are probably located in the scenic area of the Luobu people's village in Yuli County. The scenic spot has always been famous for the blending of water and sand, and some "lakes" along the way are formed by the release of ecological water from the Tarim River Basin to the original Populus euphratica forest. Other parts are multiple small "reservoirs" formed by floodplain water overflowing from the river after the warning flood occurred in the Tarim River Basin since September.
Chen Ying, chief forecaster of the Xinjiang Climate Center, said that since the flood season this year, the temperature in southern Xinjiang has continued to rise. The average number of high temperature days in southern Xinjiang in summer is 29.7 days, 7.6 days more than normal, ranking first in the same period of history. Affected by the high temperature, the snow cover in most mountainous areas of southern Xinjiang in the first ten days of May was higher than that of the same period in previous years, while that in mid-September was 40% to 80% less. In August, the average precipitation in southern Xinjiang was 105% higher than normal in the same period.
Chen Ying explained that most of the northern tributaries of the Tarim River come from the Tianshan Mountains, while most of the southern tributaries come from the Kunlun Mountains. High temperature and snowmelt combined with frequent rainfall caused super-warning floods in various tributaries of the Tarim River. From late May to late September this year, the main stream of the Tarim River was flooded for 80 days.
Based on the above reasons, the Tarim River overflows in the Taklamakan Desert, forming many "lakes". As a result, large areas of the desert were flooded, and it looked like lakes appeared in the desert.
Some experts also said that these "desert lakes" are actually accumulated water formed by local heavy rains, natural seepage and ecological water release. The accumulated water has not penetrated into the desert, so it looks like a lake in the low-lying place, but it will disappear soon, and it is not actually a lake.
"Loulan Oasis" will reappear?
In recent years, with the warming and humidification of southern Xinjiang and northwest becoming more and more obvious, some netizens are concerned whether the "Loulan Oasis" can be reproduced?
In this regard, Yao Junqiang, deputy director of the Urumqi Institute of Desert Meteorology of the China Meteorological Administration, said that the trend of accelerated climate warming is certain, but the trend of increasing precipitation in southern Xinjiang is not significant. In addition, the precipitation itself is very small and the increase is limited. The huge evaporation demand caused by warming cannot be met, so drought will still be the main situation.
Yao Junqiang pointed out that desert lakes objectively exist in many deserts in the world, and are generally relatively wide waters formed by water accumulation in depressions on the surface of deserts for a long time. The lakes in the Taklimakan Desert are mainly affected by the incoming water from the upper reaches of the Tarim River. If there is too much incoming water from the upper reaches, it will overflow on both sides of the river to form temporary waters. The Taklamakan Desert Lake, which was recently formed by the Ta River flood in summer, is such a temporary water area.
At the same time, Yao Junqiang added that desert lakes can evaporate lake water into water vapor and add it to the atmosphere to participate in the water cycle through the evaporation process, but this part of the water vapor content is very small and cannot directly affect the precipitation process. In large deserts and high-temperature environments, the cooling effect of lakes is also very limited, and most of these desert lakes will disappear through evaporation and seepage within the season.
Therefore, Yao Junqiang believes that after consulting relevant research results, it can be found that the number of small lakes in the Tahe River Basin has not increased in recent years, so the probability of long-term oases in the desert is not high.
"Extreme weather events" frequent?
Last summer, there were local floods in the Taklimakan Desert, and at the end of the year, there was a large-scale snowfall in the Taklimakan Desert; recently, "lakes" appeared in the Taklimakan Desert...Why does the weather-related news in the Taklimakan Desert affect the public nerves?
In this regard, Yao Junqiang explained that this aspect reflects that our science popularization is not strong enough. The public is easily confused and unable to distinguish between "extreme weather events" and "climate events", and regards extreme events with low probability as "climate events". There will be some unscientific cognitions such as "changing Jiangnan" and "warm and humid climate".
On the other hand, some self-media expressions are not standardized, which is also the main cause of misunderstanding. When heavy rain occurs around the desert, and then floods or accumulated water are formed, many media will describe it as "torrential rain in the desert", which is contrary to scientific common sense.
Mao Weiyi, a researcher at the Urumqi Institute of Desert Meteorology of the China Meteorological Administration, pointed out that for the locals in Xinjiang, especially those who are familiar with the climate in southern Xinjiang, floods in the Tarim River and accumulation of water and snow in the desert are not uncommon, just like encounters in coastal areas. Like a typhoon. All the local weather processes in southern Xinjiang will occur in the desert, such as heavy rain, lightning and thunder, but the frequency of occurrence is less. There are not only strong winds and sandstorms in the desert. These weather processes, which are already very common, require the public to view them rationally and objectively.
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