Recently, Associate Professor Li Pengfei and Dr. Hu Jinfei from Xi'an University of Science and Technology (XUST), together with Researcher Mu Xingmin and Researcher Zhao Guangju from the Institute of Soil and Water Conservation, Ministry of Water Resources, Chinese Academy of Sciences, Associate Researcher Liu Bintao from Chengdu Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Professor Joseph Holden from the University of Leeds, Professor Wu Peili from the UK Meteorological Center, and Associate Professor Faith Chan from the University of Nottingham Ningbo, published a paper entitled "Determining thedrivers and rates of soil erosion on the Loess Plateau since 1901". Chan and other researchers published a paper entitled "Determining thedrivers and rates of soil erosion on the Loess Plateau since 1901" in Science of the TotalEnvironment.
Hundred-year erosion evolution pattern of Loess Plateau
New advances in research
This study by Pengfei Li establishes for the first time a year-by-year grid point data series of soil erosion rates on the Loess Plateau from 1901 to 2016, analyzes the temporal and spatial evolution characteristics of soil erosion on the Loess Plateau for more than 100 years, and reveals the driving mechanism of soil erosion pattern evolution, which is important for promoting ecological protection and high-quality development in the Yellow River Basin. By compiling historical precipitation data, low- and medium-resolution land use, soil properties and other data, the researchers break through the difficult problem of estimating the distribution of vegetation cover and soil conservation measures by integrating land use data with historical vegetation cover simulation, and adopt the Revised Universal Soil Loess Equation (RUSLE). Equation (RUSLE) to assess the interannual variation of soil erosion on the Loess Plateau from 1901 to 2016.
The study compared the measured sand transport in 22 small and medium-sized watersheds that are less affected by human activities with the simulation results of RUSLE model, and the results showed that the model simulation accuracy is high and the model can be used for soil erosion assessment in the Loess Plateau region. The erosion rate changes between different eras show that the average erosion rate and erosion area of Loess Plateau increased sharply from 1930s to 1970s, and the average soil erosion rate of Loess Plateau decreased from 1980s to the first decade of 21st century, and reached the lowest value at the beginning of this century. 2010-2016, the average erosion rate rebounded again. Prior to 2010, land use change was the main driver of erosion rate change. The average erosion rate increased again during the period 2010-2016 due to the frequent occurrence of extreme rainfall events. Extreme weather events such as heavy rainfall may become more frequent in the future under climate change, thus the Loess Plateau urgently needs innovative erosion control strategies to secure regional water supply while reducing the risk of soil erosion disasters during extreme events.
Doing scientific research can not be allowed to fish for three days and sunbathe for two days
From the time he was a student, Li Pengfei was determined to do the ideal of scientific research, he also knows that this road is boring and even difficult, so in his eyes to do scientific research can not be half-slack, never three days to fish and two days to sunbathe. He said so and did so. Just since he joined the university in 2017, he has published 32 academic papers, declared 2 patents, presided over 3 national funds, 1 joint fund project of national funds, 1 fund of the Department of Education, and 2 horizontal projects.
In recent years, he is mainly engaged in the research of soil erosion process and its model simulation on Loess Plateau. He has developed the world's first peatland water erosion model, PESERA-PEAT, which has been applied to regional, national and global scales to assess the impact of climate and land use change on peatland soil erosion. In the study of soil erosion processes and mechanisms on the Loess Plateau, we have systematically summarized the soil erosion models applied to the Loess Plateau since the 1980s, analyzed and compared the prediction accuracy, process representation, data and calibration needs, and scenario simulation capabilities of 11 soil erosion models that have been applied to the Loess Plateau, and provided a reference for the future development of soil erosion models on the Loess Plateau, which was published in The results were published in Earth-Science Reviews, a top journal in the field of earth sciences. Currently, we focus on the research of soil erosion monitoring methods, processes and mechanisms of the Loess Plateau slope and gully system, using advanced remote sensing techniques such as 3D laser scanning and photogrammetry to study multi-scale soil erosion processes, and on this basis, we explore soil erosion simulation methods of the Loess Plateau to simulate the response of erosion to climate change and human activities. His representative research results have been published in top journals such as Remote Sensing of Environment and Science of the Total Environment.
Erosion of Northern Hemisphere blanket peatlands under 21st-century climate change" is a scientific research result published by Pengfei Li as the first author in Geophysical Research Letters. Peatlands store one-third of the Earth's soil carbon and are an important carbon reservoir globally, especially in the northern hemisphere. A large number of peatlands around the world are suffering from erosion hazards, leading to regional water quality degradation and soil carbon loss. How peatland erosion will change under climate change remains unclear. The study used seven Global Climate Model (GCM) simulations to drive the PESERA-PEAT model to investigate how peatland soil erosion will change in the Northern Hemisphere under climate change in the 21st century. The results show that under most GCM-derived climate change scenarios, peatland erosion rates will increase in 2070-2099 (2080s) after an initial decline compared to the base period (1961-1990), and regional variability in erosion intensity is evident during 2070-2099, ranging from -1.27 to +21.63 t ha-1 y Peatland erosion variability is mainly due to changes in temperature and precipitation, with temperature variability being the dominant factor. Peatlands at low latitudes and warm regions face the highest erosion risk under the 21st century climate change.
Dedicated research to solve scientific problems
Dr. Pengfei Li was engaged in soil erosion process model simulation research during his graduate studies, and participated in the development and application of PESERA, a large-scale soil erosion process model developed by the University of Leeds, UK. To develop and improve the model, a deep understanding of the processes and mechanisms under study is required. In the field of soil erosion, traditional monitoring methods are difficult to achieve fine monitoring of spatial and temporal changes of erosion, which limits the understanding of erosion processes and mechanisms, and thus restricts the development of models. Efficient monitoring methods for soil erosion have become a bottleneck for advancing erosion research.In 2017, the problem was brought to work at Xi'an University of Science and Technology. After joining, the university's emphasis on basic theoretical research, especially on the declaration of the National Natural Science Foundation of China, has both pressured and encouraged him. The university attaches great importance to the cross-fertilization of disciplines and strongly advocates the use of advanced technical means of surveying and mapping disciplines to solve scientific problems in geography. Inspired by this idea, he discussed deeply with experts inside and outside the institute, and gradually found the idea of solving erosion process research from the means of high-precision monitoring by remote sensing of mapping, and then tried to introduce the advanced remote sensing technology method into erosion research, and found the method of high-precision research of erosion process, and also successfully approved the NSF youth fund project, surface project, and Sino-German Center project of NSFC, etc. He has also been successfully approved by the National Natural Science Foundation of China (NSFC) for youth projects, surface projects, and Sino-German Center projects.
In 2019, Li Pengfei's approved NSF surface project "Spatial and temporal characteristics and driving mechanisms of gravity erosion in the Loess Hills and Gullies" has an application on this problem. Gravity erosion is serious in loess hilly gully areas. There are many factors influencing gravity erosion and non-linear superposition, which leads to a strong randomness of its occurrence and is not conducive to monitoring and research. As a result, the spatial and temporal characteristics and driving mechanisms are seriously under-researched, which restricts the development of soil erosion process models. The project takes Qiaogou, a typical watershed in the Loess Hills and Gullies area, as the research area. Through LiDAR 3D terrain scanning, GNSS measurement, field survey, positioning observation, sampling analysis and numerical simulation, the project studies the spatial and temporal distribution characteristics of three types of gravity erosion in the watershed, such as landslide, landslide, and cascade, and elucidates their spatial and temporal change patterns and development processes; analyzes the change characteristics and relationships of gravity erosion influencing factors, and elucidates the development of gravity erosion driving factors. Based on the previous results and existing theories and methods, a model considering soil stability, destabilization probability and gravitational erosion is constructed and coupled with the PESERA-LP model to form a regional scale soil erosion process model suitable for the loess hills and gullies. The model is coupled with the PESERA-LP model to form a regional scale soil erosion model suitable for the loess hilly gully area. It can provide theoretical basis and assessment tools for soil and water conservation and ecological restoration on the Loess Plateau.
Talking about future planning, Li Pengfei said, "In 2018, the discipline of surveying and mapping was approved as a first-class discipline doctoral point, and the School of Surveying and Mapping has entered a new stage of development, which requires higher quality development. At present, he is presiding over the administrative work of the college, and in the future, he will lead the college needs to focus on promoting the discipline, scientific research and talent team construction, and help the college to develop with high quality. I personally will also lead the team to do scientific research in the motherland, continue to deepen the 'remote sensing of landforms and soil and water conservation' research, and strive to produce more and better results, to achieve better promotion and application of the results.
Now, Li Pengfei is both the head of the discipline team and the vice president of the School of Surveying and Mapping, so it is a big challenge for him to balance teaching and research with administrative work! Especially since August 2021, when he presided over the administrative work of the college, the challenge of balancing business and administration has always existed. Li Pengfei said: To balance business and administration, there is no good way but to strengthen ourselves, improve efficiency and invest more time and energy. The future is long and difficult, but what we see in Li Pengfei's eyes is full of starlight!
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