Xinhua News Agency, Xining, August 21 ST, in the source area of the Yangtze River in summer, the meadow is as green as a carpet; Against the blue sky and white clouds, the lake is as calm as a mirror. Located in the source area of the Yangtze River on the Qinghai-Tibet Plateau, lakes, large and small, are like pearls embedded in the plateau, which are particularly eye-catching.
This is the lake group (photo of drone) taken in the source area of the Yangtze River on July 23rd, 2021. Xinhua News Agency reporter Zhang Long photo
As an important part of the "China Water Tower", large and small lakes are important water ecological storage devices in the source area of the Yangtze River, and also an important guarantee for realizing the "one river of clear water flowing eastward" of the Yangtze River. The change of lake area and water quality in the source area of the Yangtze River is also the focus of the comprehensive scientific research of the Yangtze River source in 2021.
Zhu Liping, head of the Lake and Environment Change Team of the Institute of Qinghai-Tibet Plateau, Chinese Academy of Sciences, said that the Qinghai-Tibet Plateau, where the Yangtze River source is located, is widely distributed, with more than 1,400 lakes with an area of over 1 square kilometer, making it one of the highest altitude, largest number and largest plateau lake groups on earth.
According to the scientific research data of the Yangtze River Academy, there are more than 11,000 lakes in the source area of the Yangtze River, with a lake area of about 1,027 square kilometers. "Judging from the scientific research in recent years, the water quality of lakes in the source area of the Yangtze River has remained excellent, but the area growth has become a common phenomenon." Xu Ping, deputy chief engineer of Changjiang Academy of Sciences, said that in the past 40 years, the total area of lakes and wetlands in the source area of the Yangtze River has increased by 7.2%.
This is a group of lakes (drone photo) taken in the source area of the Yangtze River on July 23rd, 2021. Xinhua News Agency reporter Zhang Long photo
Take Quemocuo Lake as an example. This lake is about 26 kilometers away from the front of Geladandong Snow Mountain, the birthplace of the Tuotuo River in Zhengyuan, the Yangtze River. In 2000, its area was less than 80 square kilometers, and now it has exceeded 97 square kilometers, with an average annual growth rate of nearly 1%.
Scientific research found that the warming and humidification of the source area of the Yangtze River is the main reason for the obvious increase of the lake area. The average temperature and precipitation in the source area of the Yangtze River in the past 10 years have increased by 1.4 degrees Celsius and 39.6 mm respectively compared with those in the previous 40 years, and the trend of warming and humidification is very obvious.
According to long-term observation data, in the past 40 years, the lake wetland area in the source area of the Yangtze River has increased by an average of about 100 square kilometers for every temperature increase of 1 degree Celsius. According to Xu Ping, the degradation of glaciers and the melting of frozen soil caused by warming, and the increase of precipitation will increase the inflow of lakes, which will lead to the external expansion of the lake coastline and the increase of the lake area.
Tan Debao, deputy chief engineer of the Yangtze River Academy of Sciences, said that lake wetlands can not only effectively regulate the water delivery from the source of the Yangtze River and the local climate environment, but also be an important habitat for a variety of organisms. "The increase in lake area and excellent water quality are conducive to improving the regulation and storage capacity of water ecology in the source area of the Yangtze River and better protecting biodiversity, but at the same time it will also cause some potential hidden dangers, which need continuous attention and in-depth research."
This is a photo of Zhuonaihu Tibetan Antelope Aggregation (unmanned aerial vehicle) in Hoh Xil region taken on July 8, 2020. Xinhua News Agency reporter Zhang Long photo
According to the scientific research observation, some lakes in the source area of the Yangtze River have increased in area and water level, and some lakes that used to be independent of each other have formed a connected water system due to new rivers. The continuous increase of the lake surface is also likely to adversely affect the ecological environment of the grassland and the adjacent infrastructure.
Tan Debao said that the increase of lake area and the rise of water level are the topics that must be paid attention to in the scientific research and protection of the source of the Yangtze River. "The scientific research of the source of the Yangtze River will continue to study the laws behind the increase of lake area and provide more systematic and professional scientific research support for the water ecology and water environment protection in the source area of the Yangtze River." (Reporter Li Jinfeng, Chen Jie, Zhang Long)
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