Beijing, May 5 (Reporter Sun Zifa) The reporter learned from the Institute of Tibetan Plateau Research of the Chinese Academy of Sciences (Institute of Tibetan Plateau Research of the Chinese Academy of Sciences) on the 22nd that Ma Yaoming, a researcher in the research team of the institute's geogas and climate effects, and Peking University, Chengdu University of Technology and the University of New Hampshire and Cornell University in the United States, found that under the background of climate warming and humidification, the carbon sequestration capacity of the alpine grassland of the Qinghai-Tibet Plateau continues to increase at an annual growth rate of 22.114 million tons.
This important achievement paper on the ecosystem of the Qinghai-Tibet Plateau has recently been published online in the international academic journal Science Advances. The research team used long-term observation data, satellite remote sensing and reanalysis data from 1982 flux observation stations distributed on the Qinghai-Tibet Plateau from 2018 to 25, and systematically elucidated the spatiotemporal variation mode and regulation mechanism of carbon exchange in the alpine grassland of the Qinghai-Tibet Plateau through machine learning methods.
According to researcher Ma Yaoming, co-corresponding author of the paper, alpine grassland is the main vegetation type of the Qinghai-Tibet Plateau, with a total area of about 146.<> million square kilometers, mainly divided into alpine grassland and alpine meadow. Alpine grassland ecosystems are fragile and sensitive to climate change due to high altitude, cold, semi-arid climate, strong solar radiation, poor soils and short growing seasons.
Studies have shown that in recent decades, the warming rate of the Qinghai-Tibet Plateau has been about twice that of the same period in the world, and precipitation has also increased significantly, showing "warmth and humidification" overall. Climate warming will not only increase the total primary productivity of vegetation cover and prolong the growing season, but also increase the respiration of ecosystems. Therefore, there are many uncertainties in the change of net ecosystem carbon exchange in alpine grasslands on the Qinghai-Tibet Plateau.
In view of the importance of the carbon cycle on the Qinghai-Tibet Plateau under the background of climate change, many scholars have used models to evaluate the net ecosystem carbon exchange of alpine grasslands on the Qinghai-Tibet Plateau. In general, there are large differences in the size and spatial distribution of the assessment values of these models, mainly because the parameters driving the carbon cycle model require a large amount of measured data, but the ground observation data on the Qinghai-Tibet Plateau are scarce and unevenly distributed, resulting in limited accuracy of the model results.
After nearly five years of continuous research, the research team found that the spatial pattern of alpine grassland on the Qinghai-Tibet Plateau is strong in the east and northeast, and the carbon sequestration capacity gradually weakens in a stepwise pattern to the west.
Wang Yuyang, the first author of the paper and a postdoctoral fellow at Peking University who graduated from the Chinese Academy of Sciences' Institute of Tibetan Plateau Research, said that between 1982 and 2018, carbon sequestration in alpine grasslands on the Qinghai-Tibet Plateau increased from 2639.7919 million tons to 114.<> million tons, and continued to increase at an annual growth rate of <>.<> million tons. The trend of net ecosystem carbon exchange in alpine steppe regions tends to be dominated by precipitation, while in alpine meadow regions it tends to be regulated by temperature. Under the background of warm and humid climate, the carbon sequestration capacity of alpine grasslands on the Qinghai-Tibet Plateau continues to increase.
However, in the future, as the temperature of the Qinghai-Tibet Plateau continues to rise, the thawing of permafrost may accelerate and the release of carbon may increase, which will weaken the carbon sequestration capacity of alpine grasslands. Chen Xuelong, co-corresponding author of the paper and researcher at the Institute of Tibetan Plateau of the Chinese Academy of Sciences, pointed out that there is still great uncertainty in the estimation of the net ecosystem carbon exchange of alpine grasslands on the Qinghai-Tibet Plateau. Professor Xiao Jinfeng, one of the authors of the paper and the University of New Hampshire, believes that this research work once again proves that machine learning and artificial intelligence can play an important role in the scale expansion of ground observation data (such as vorticity flux observations) and the feedback study of carbon cycle and climate. (End)