1. Biographical information

GuoDong Cheng, born on 11 July, 1943, in Shanghai, China, received his Bachelor of Science in 1965, from the Department of Hydrogeology and Engineering Geology at Beijing Geology College (now China University of Geosciences). In the same year, he started his research career at the Lanzhou Institute of Glaciology, Geocryology, and Desert Research, Chinese Academy of Sciences(CAS). Over the past 45 years, Professor Cheng has published more than 200 papers in peer-reviewed professional journals and books. Professor Cheng has made fundamental contributions to permafrost science. Because of his long-term research and great achievements in geocryology, he has been recognized as one of the leading geocryologists both in China and in the international permafrost community. He was and still is an outstanding leader in scientific community. Professor Cheng has excellent records in training young scientists and graduate students, conducting scientific community service and general public outreach, and promoting national and international scientific exchange. During the past 10 years, he has been focusing his research on ecological hydrology and ecological economy in cold and arid regions, with remarkable successes.

2. Outstanding national and international leadership in scientific research

Over the past 45 years of his career, Professor Cheng’s scientific contributions reach far beyond geocryology, especially his outstanding records of leadership in various positions. These leadership positions ranged from group leader, division head, director of research institutes, president and deputy president of national and international scientific societies and associations. He served as Director of the Lanzhou Institute of Glaciology and Geocryology, CAS, from 1991 to 1999; director of the Cold and Arid Regions Environmental and Engineering Research Institute, CAS, from 1999 to 2001; and Director of the State Key Laboratory of Frozen Soils Engineering from 1996 to 2005. He also served as Vice-President and President of the International Permafrost Association during the periods of 1988 to 1993, and 1993 to 1998, respectively.

Professor Cheng is currently President of the CAS Lanzhou Branch, Vice-Chairman of Gansu Association of Science and Technology, Deputy President of the Chinese Geographical Society, Deputy President of the China Association of Ecological Economy, Director-General, Department of Geosciences, the National Natural Science Foundation of China (2007 and onward), Chief Editor of theJournal of Glaciology and Geocryology(in Chinese),Journal of Ecological Economy(in Chinese), andSciences in Cold and Arid Regions(in English). He is also on the editorial board of two internationally recognized journals,Cold Regions Science and TechnologyandPermafrost and Periglacial Processes, and a Chinese journal,Science in China,Series D–Earth Sciences. He was elected as an Academician of the Chinese Academy of Sciences in 1993.

3. Representative research accomplishments

(1) Mitigation of permafrost-related engineering problems for the construction of the Qinghai-Tibet Railway

At present, more than 30% of the railway roadbed is severely impacted by frost damage in permafrost regions worldwide, and construction of railroads in cold regions is still a great challenge for permafrost scientists and engineers. It is even more difficult task when the impact of climate change is considered in the design and construction.Professor Cheng, based upon the occurrence and distribution of permafrost under natural conditions, evaluated the conventional method of passively preserving permafrost by increasing thermal resistance, and concluded that this traditional preservation was inadequate for ensuring long-term engineering stability. He invented a new, active cooling approach, namely "cooled roadbed" over permafrost, using a series of techniques to preserve permafrost by modifying road surface conditions, controlling the amount of solar radiation reaching the ground, and adjusting heat convection and conduction patterns in the roadbed. The mechanism of these engineering methods and their effectiveness were verified through field prototype and laboratory experiments, and numerical modelling. One of these techniques is to use a crushed rock layer over on embankment to successfully cool underlain permafrost, which is economically sound and extremely environmentally friendly. One of his papers, "The semi-conductor effect of crushed rocks," was reviewed in "Research Highlights" byNature China(Nature China, Published online 6 June 2007, doi:10.1038/nchina.2007.98).

This new, active cooling approach was well accepted by the Ministry of Railways of China, and has been widely applied to the design and construction of the Qinghai-Tibet Railroad. The Qinghai-Tibet Railway began operations on July 1, 2006. Up till the present, the roadbed has been stable, and the train speed is up to 100 km/h,which is the highest record for trains in permafrost regions of the world. Fifty-six permafrost scientists and engineers from 17 countries including Russia, Canada, the United States of America, Austria, Japan, and China inspected the Qinghai-Tibet Railway after the Asia Permafrost Conference in August of 2006. They unanimously agreed upon the success and superb quality of the "cooled roadbed" design and construction method. "The Qinghai-Tibet Railway represents the latest development of permafrost engineering," said Dr. Jerry Brown, then President of the International Permafrost Association, "Other countries can learn from China’s achievements in this field." In his paper titled "The Tibetan Railroad: Innovative construction on warm permafrost in a low-latitude, high-altitude region," the famous Canadian geocryologist, Professor Stuart A. Harris, pointed out: "From an international point of view, the railroad represents an important milestone in the development of methods of construction on "warm"permafrost. The experience gained by this project will undoubtedly have far-reaching effects on the design of future engineering projects in this type of environment."

(2) Cheng Hypothesis–Theory of Repeated Ice Segregation Mechanism

Professor Cheng discovered the Repeated Ice Segregation Mechanism for the formation of near-surface rich ground ice in permafrost regions, which resolved a long-disputed key theoretical issue in geocryology, and was later recognized as the "Cheng Hypothesis" by the international permafrost community. Canadian scholars conducted observational experiments at field stations for three years in order to validate the hypothesis. Their results, based upon both the field and laboratory observations,confirmed Professor Cheng’s conclusion. This achievement was awarded the Natural Science Award of the Chinese Academy of Sciences in 1993. He also proposed a three-dimensional zonation model for classifying high-altitude permafrost in middle and low latitudes, which was well received and extensively cited by international colleagues. As a result, he was invited many times to present keynote speeches at international conferences. His classification of high-altitude permafrost based upon the thermal stability of the ground thermal regime has been widely applied in engineering practices in recent years. As the leader of the Taskforce on the Impact Assessment of Climatic Change on Snow Cover, Glaciers and Permafrost in China, Professor Cheng drafted a national report on "Assessment of and Countermeasures to the Impact of Climatic Change on China," part of which was later submitted by the Chinese Government to and was adopted by the Intergovernmental Panel Climatic Change (IPCC). The publication of this report has greatly promoted research programs both on climatic change and on Cryospheric research in China.

(3) Establishment of interdisciplinary and integrated research network in arid and semi-arid regions in China

As Chief Scientist, Professor Cheng proposed and implemented an interdisciplinary and integrated research framework focusing on water and also encompassing complex interactions of hydrology, ecology and economy on a watershed scale. He proposed and promoted the 3-M (Monitoring, Modelling and Manipulating) research platform. His research team has built a preliminary "Digital Heihe Watershed," providing a platform for integrated and interdisciplinary studies. Professor Cheng has paid great attention to research on arid and semi-arid regions ecological hydrology, which has significantly advanced the development of ecological hydrology in arid and semi-arid regions in China. He also enthusiastically promoted ecological economy in China, encouraging the transformation from traditional social science to interdisciplinary studies that combine both social and natural sciences, with great success.

(4) Initiation and enhancement of international scientific exchange and collaboration

Professor Cheng was one of a few early scientists who visited the United States and Canada and initiated international scientific exchange in the late 1970s. The international cooperation program later expanded into many other countries such Russia, Mongolia. He organized the Sixth International Conference on Permafrost in Beijing during the summer of 1993. More than 500 scientists and engineers from more than 30 countries attended the conference. During the conference, he was elected as the President of International Permafrost Association. Working closely with International Permafrost Association, Professor Cheng organized the 1stAsian Conference on Permafrost in August of 2006 and led delegates to tour milestone project– Qinghai-Tibet Railroad. He served as a Co-Chairman of 3rdto 7thInternational Symposium on Permafrost Engineering held in 1988, 2000, 2002, 2004, and 2007, respectively. He was also a Co-Chairman of the International Symposium on "Sustainable Water Resources Management and Oasis-hydrosphere-desert Interaction in Arid Regions" in 2005.