The desert turns into a "lake"! What happened to the Taklimakan Desert?

Produced by: Science Popularization China

Author: Shi Chang (PhD in Physical Chemistry)

Producer: China Science Expo

When we talk about deserts, we think of a vast expanse of "golden ocean" composed of countless tiny sands and dunes. Another prominent feature of deserts is that they are dry and rainless. The annual precipitation in deserts is less than 250mm. The average annual precipitation in the Taklimakan Desert in Xinjiang, China does not exceed 100mm, and the lowest is no more than 10mm.

desert

(Photo source: veer photo gallery)

But did you know that arid deserts can also experience floods? According to CCTV News, a "desert flood" scene recently appeared in the Taklimakan Desert in Xinjiang, attracting the attention of netizens. A short-term flood suddenly occurred on some sections of the G580 Desert Highway in Luopu County, Xinjiang, located in the heart of the Taklimakan Desert. The road surface was submerged, causing traffic obstruction. After more than 20 hours of guidance and drainage by local traffic police and road maintenance departments, this section of the road was restored to normal traffic.

Why is there a lack of water in the desert?

Deserts are mainly divided into two categories: tropical deserts and temperate deserts. The representative of tropical deserts is the Sahara Desert in northern Africa, which is the largest sandy desert in the world. Since North Africa is controlled by the subtropical high-pressure belt all year round and the prevailing sinking air flow, the dry and hot environment of the Sahara Desert is created. In addition, the eastern part of North Africa is adjacent to Asia, and the northeast trade winds blowing from the eastern land are not conducive to precipitation, further exacerbating the water shortage in the desert area.

Dry, hot and water-scarce land

(Photo source: veer photo gallery)

The Taklimakan Desert is a representative of temperate deserts. It is located in the northwest of China, deep inland and far from the ocean, so it is difficult for water vapor from the ocean to reach it. On the other hand, the area is located in the Tarim Basin, surrounded by high mountains such as the Tianshan Mountains and the Kunlun Mountains. The terrain is relatively closed, and it is difficult for rainfall to form in this area.

In desert areas, even if there is occasional heavy rainfall, it is difficult to retain moisture due to high ambient temperature, high evaporation, and low vegetation cover. "Few sources and inability to retain water" have caused water shortages in desert areas.

Rare plants in the desert

(Photo source: veer photo gallery)

Where do desert floods come from?

Although the flood in the Taklimakan Desert is rare, it is not the first time. In July 2021, a flood broke out in the Taklimakan Desert, flooding an area of ​​more than 300 square kilometers, causing the destruction of a large number of equipment and vehicles. So where does the water come from?

Flooding flooded the road

(Photo source: veer photo gallery)

Although Xinjiang is located deep inland and far from the ocean, floods occur from time to time. The main sources of flood disasters in Xinjiang are melting ice and snow, seasonal heavy rains and river bursting .

Friends who have been to Xinjiang must have seen icebergs. Since there are many mountains in Xinjiang, the high mountains will block some water vapor, forming precipitation and snow in the mountains. On the western edge of the Tarim Basin in Xinjiang, there is a peak called Muztagh Ata, which is known as the "Father of Icebergs". With the rise of global temperatures and the rise of temperatures in spring and summer, the ice and snow on the icebergs in Xinjiang will partially melt , causing the water level in the rivers to rise, bringing the hidden danger of floods.

Snow Mountain

(Photo source: veer photo gallery)

Although Xinjiang is drier than other regions, seasonal rainstorms occur in the spring and summer in the middle and low mountain areas due to the influence of climate and topography. The desert is mainly composed of sand, the gaps between sand particles are large, and the water infiltration rate is relatively fast. However, although sand can quickly absorb some water, its water storage capacity is very limited. This means that under extreme precipitation conditions, when the precipitation intensity in local areas exceeds the infiltration intensity of the desert, floods will quickly form and spread. Since June 2024, the precipitation in southern Xinjiang has been significantly higher than last year, and the Yingbaza River section of the middle reaches of the Tarim River has also experienced the largest flood since measured data.

In addition, due to the large number of mountains in Xinjiang, natural disasters such as mudslides and landslides are prone to occur . When the amount of water is too large, the dam or river channel will collapse instantly, and the water will suddenly leak, which is far more destructive than ordinary rainstorm floods or snowmelt floods. On August 3, 2024, drone footage showed that the Tarim River in Shaya County, Aksu Prefecture, Xinjiang, had widened due to the impact of floods.

mudslide

(Photo source: veer photo gallery)

Why have heavy rains occurred so frequently in recent years?

The China Climate Change Blue Book (2024) released by the China Meteorological Administration points out that the global warming trend is still continuing, and the global average temperature will reach its peak in 2023 since meteorological observations were first recorded in 1850. Since warm air contains more water than cold air, once precipitation occurs, the amount of precipitation will be relatively large, which is very likely to cause flooding.

Dark clouds before the rainstorm

(Photo source: veer photo gallery)

In the process of global warming, the monsoon has also undergone some changes. In 2019, a study by the Institute of Atmospheric Physics of the Chinese Academy of Sciences pointed out that over the past century, the global land monsoon area has been greatly affected by global warming, and extreme precipitation has shown an overall increasing trend. For land, the monsoon area contributes a large amount to the total precipitation and is prone to extreme precipitation. The global monsoon area spans the tropics and subtropics, and is accompanied by abundant monsoon water vapor transport, which is the main source of extreme precipitation.

When heavy rain comes, how to protect yourself?

Avoid subways, underground shopping streets, culvert tunnels and other areas : these areas are low-lying and difficult to drain, making them very likely to become the hardest hit areas by waterlogging.

Parking lot water

(Photo source: veer photo gallery)

Stay away from hillsides and other areas : Heavy rain can easily trigger natural disasters such as landslides and mud-rock flows, which have strong impact and destructive power. They can form and flow quickly in a very short time, destroying buildings, roads and bridges along the way.

Stay away from electrical equipment : When passing through a flooded road on a rainy day, pay attention and keep a distance from electrical equipment in the flooded area. When the water exceeds the curb, try to avoid wading, as the water may cause cable leakage.

Flooding submerged vehicles

(Photo source: veer photo gallery)

Pay attention to driving safety : Visibility is extremely low in rainstorms. When driving, you should not only reduce your speed, but also keep a safety hammer in the car. The water on the road rises quickly during rainstorms. If the vehicle cannot drive normally, you should leave the vehicle in time and use a safety hammer to break the window to escape if necessary.

Pay attention to food safety : After a rainstorm, try not to drink raw water, only drink boiled water or bottled or barreled water that meets hygiene standards. When drinking temporary water sources such as well water and river water, be sure to disinfect them. Do not eat food that has been soaked by flood water.

The frequent occurrence of extreme weather not only tests our ability to respond, but also strengthens our determination to protect the environment. In life, we must start from the details, take practical actions to protect our home planet, and jointly protect the environment on which we depend for survival, so that there will be fewer disasters and more peace and beauty in the future.

References:

1.Zhang W, Zhou T.Significant Increases in Extreme Precipitation and the Associations with Global Warming over the Global Land Monsoon Regions[J].Journal of Climate, 2019.

2.Zhong-Xiao L, Li-Ma GE,Haimidyimit, et al. Changes of Average Air Temperature and Rainfall in Urumqi Under Background of Global Warming[J]. Journal of Arid Land Resources and Environment, 2007.

3. Li Jiangfeng. Weather and climate of the Taklimakan Desert and surrounding mountainous areas[M]. Science Press, 2003.

4. Thomas T. Werner. Desert Meteorology (fine) [M]. Meteorological Press, 2008.