Permafrost research in China during the years of 2010 and 2011 continues actively on the following issues: permafrost investigations at representative areas, permafrost ecology and hydrology on the Qinghai-Tibet Plateau (QTP), including that in the Qilian Mountains on the northern edge of the QTP, monitoring and engineering experimental studies of permafrost roadway and railbed along the Qinghai-Tibet Highway (QTH) and Qinghai-Tibet Railways (QTR) from Golmud to Lhasa and along the upgrading Qinghai-Kang (West Sichuan Province) Highway (QKH) from Golmud to Yushu (NH G214), monitoring and modeling studies of permafrost and pipeline engineering in Northeastern China, as well as the study on the extent of permafrost in China during the Last Glaciations Maximum (LGM) and the Megathermal. In the same time, some new science and engineering research programs have been proposed and are under evaluation, such as the cryospheric change and its impact assessment and adaption, Trans-Tianshan Expressway from Urumqi to Yuli. In particular, the experimental station for highway engineering at Huashixia along the QKH has been relocated to the east of Modoi, and a new research base on permafrost environment and cold regions engineering is being built at Mo’he, the northernmost point in Northeastern China. Altogether, 123 boreholes, 30 active layer process sites, 18 automatic weather stations, and 6 carbon cycle sites have been established and in operation for long-term monitoring (Figure 1 and Table 1).
Figure 1. Distribution of permafrost in China and bordering regions, and boreholes for monitoring the thermal state of permafrost.
Table 1. Summary of TSP, ALP, AWS and CC in permafrost regions in China (incomplete statistics, could be about 100 off as some new holes and boreholes from certain sources were not included, and all sites impacted by engineering activities were excluded. Note: QTR/H --- the Qinghai-Tibet Railway/Highway; SAYR --- the Source Area of the Yellow River; QLM --- the Qilian Mountains; QKH --- Qinghai-Kang (Western Sichuan) Highway; Others include Eastern Tianshan, Southern Altai and Western Kunlun Mountains.
Permafrost Survey on the QTP
The survey on the permafrost extent of about 200,000 km2 (between 78.83°-86.13°E and 35.98°-33.03°N) and with an average elevation of 4,900 m. The surveyed areas include the continuous permafrost on the Qiangtang Plateau in the Interior QTP and the transitional areas in the northwest and southwest.
The fieldwork includes total length of drilling and casing of 858 m in permafrost: 51 boreholes for long-term monitoring of permafrost, with depths from 6 to 53 m and at elevations at 4,300 to 5,225 m. Two new sites for the active layer processes were also deployed at Tianshui’hai in the Western Kunlun Mountains and at Gumu in the western Qilian Mountains. Soil samples for physical, chemical and biological properties were obtained from 87 soil profiles and 93 vegetation plots. About 100 ground penetration radar (GPR) profiles were conducted, with a total length of 55 km. Through this survey, understanding on the frozen ground, vegetation and soils have been improved in Western Kunlun Mountains and in the Gaize area. Preliminary analysis indicates that the lower limit of permafrost is at 4,700 m in the Western Kunlun Mountains, whereas it is at 5,000 m in Gaize. Soils are generally very dry (halic), and vegetation is characteristic of alpine deserts or steppes.
Permafrost and ecology on the Qinghai-Tibet Plateau (QTP)
In 2010, 12 boreholes, 4 active layer process stations and 1 automatic weather station were deployed in the sources area of the Yellow River (SAYR) on the north and south slopes of the Bayan Har Mountains along the QKH. Eleven sites for monitoring the active layer processes and three automatic weather stations were established, but the accompanying boreholes were unable to be completed (Figure 2). The preliminary surveys on frozen ground, cryosols and vegetation were completed, and draft map for the distribution of frozen ground was drawn in 2011.
Figure 2. Distribution of permafrost and boreholes for monitoring the thermal state of permafrost in the sources area of the Yellow River (SAYR).
Permafrost and ecology in the Qilian Mountains
The research activities in the Qilian Mountains in 2010 include the assessment of thermal stability of Chaida’er-Muli Railway, and investigation and study on the thermal state of permafrost on the southern slopes of the Qilian Mountains.
On 28 July 2010, the program “Thermal stability of permafrost Railbed along the Chaidaer-Muli Railway” successfully passed the technical review organized by the Science and Technology Department, Qinghai Province, drawing a full conclusion of the research program since 2007. This program verified the effectiveness of thermosyphons, airducts, block railbed, and grassy protective berms in stabilizing permafrost railbed traversing the wetlands (Figures 3 to 5).
Figure 3. Application of thermosyphons along the Chaidaer-Muli Railway
Figure 4. Air-duct ventilated blocky railbed along the Chaidaer-Muli Railway
Figure 5. Side protective berm of grass mat along the Chaidaer-Muli Railway
The survey on the features of frozen ground and environments were a continuation from 2009, and the areas worked in 2010 and 2011 included the semi-humid area Datong River in the eastern Qilian Mountains, the arid areas in the sources of the Shule River in the northern Qilian Mountains, and the Yashatu in the western Qilian Mountains. The major contents for the research include features of permafrost, influences of local environmental factors on the development of permafrost and vegetation (Figure 6).
Figure 6. Monitoring site for permafrost in the arid western Qilian Mountains
In 2010-2011, four activities were undergoing: 1) Continued monitoring and maintenance of three existing sites; 2) Two automatic weather stations were installed in the sources area of the Datong River and Yashatu; 3) Surveys on vegetation in the watershed of the Datong River in a transition zone from sporadic and continuous permafrost (Figure 7), and; 4) Seven boreholes of 15 m in depth and 1 hole of 100 m in depth were deployed for monitoring the thermal state of permafrost. Preliminary results indicate that the mean annual ground temperature is -2.5°C on the mountain top, and that is close to 0°C in other boreholes.
Figure 7. Sites for vegetation surveys in the Datong River watershed
Permafrost Science and Engineering in the Northeastern China
About 34 new boreholes were added during the last two years for monitoring the thermal state of permafrost, with the deepest 80 m. In the same time, 4 active layer processes, and two automatic weather stations, and two additional AWS and snow-ALP-permafrost monitoring systems were added in studying the permafrost and snow cover processes in the forested areas in the Xing’anling Mountains.
In Gen’he permafrost station, ground temperature and meteorological data since January 2009 were obtained from the existing 8 holes. Along the CRCOP, data from 2007-2011 were obtained. Numerical and empirical analysis on the engineering geology, thermal regimes of pipeline foundations, transitional sections of various causes in particular, and frost hazards were made for the design and construction of the pipeline, which was put into operation in November 2010. The research was published in a Cold Regions Science and Technology special issue (6 May 2010, 64(3)) on China-Russia Crude Oil Pipeline in Permafrost Regions in Northeast China; Chief-edited by G Timco, and Guest-edited by H. Jin, G. Gay, and M. C. Brewer, with 10 papers. However, the oil temperatures were much higher (3-17°C) than anticipated (-4 to+6°C), significant thaw subsidence has resulted in the pipeline foundation soils during the first year of operation from November 2010 to October 2011. In the eight boreholes monitored for the thermal state of the pavement under the runway at the Mo’he Airport, data from 2006 to 2010 were collected, indicating the temperatures were relatively warm but stable.
Figure 8. Distribution of permafrost, and boreholes for monitoring the thermal state of permafrost in the Xing’anling Mountains in Northeastern China
Launching and proposing New Programs/Projects
a) There were two new projects launched during 2010-2011: National 973 Program on the Changes in the Cryosphere in the Northern Hemisphere and Their Adaptation, and; Chinese Academy of Science (CAS) Permafrost extent during the Last Glaciations Maximum and Megathermal. Two new programs were also proposed and are now under review: Super 973 on Cryosphere change and its adaptation, which includes five subprojects related to permafrost (thermal state of permafrost, carbon in permafrost regions, Hydrology in cold regions, frost hazard mitigation, and adaptive measures for changing permafrost environments) and; Investigation and mitigation of the proposed Express Highway across the Tianshan Mountains.
Huijun Jin (firstname.lastname@example.org)