Li Zongxing

Changes of the Hailuogou glacier, Mt. Gongga, China, against the background of global warming in the last several decades

Great change, associated with global warming, has occurred at the Hailuogou glacier, Mt. Gongga, China, since the early 20th century. Various data indicate that the glacier has retreated 1 822 m in the past 106 years, with an annual mean retreat of 17.2 m, and the front elevation has risen by 300 m since 1823. Comparison of glacier variations and temperature fluctuations in China and the Northern Hemisphere, over the last 100 years, indicates that glacier retreat stages occurred during the warm phase, and vice versa. Mass balance records during 1959/60-2003/04 have shown that the glacier has suffered a constant mass loss of snow and ice. The accumulated mass balance, -10.83 m water equivalent, indicates an annual mean value of -0.24 m water equivalent. The correlation between the mass balance and temperature is significant, which also indicates that climate warming is the crucial cause of glacier loss. Local hydrological and climatic data demonstrate that runoff from the glacier has been increasing both seasonally and annually. The correlation analysis and trend analysis indicate that ice and snow melted water is the main cause of an increase in the runoff. As the climate hag become warmer, changes in the glacier surface morphology have obviously occurred. These include a decrease in glacier thickness, enlargement of glacial caves, and reduction of the size of clefts on the glacier surface. The ablation period has lengthened and the ablation area has expanded. A variety of factors thus provide evidence that the Hailuogou glacier has suffered a rapid loss of snow and ice as a result of climatic warming.

Chemistry of snow deposited during the summer monsoon and in the winter season at Baishui glacier No. 1, Yulong mountain, China

The glaciers on Yulong mountain (5596 m a.s.l.), China, are the southernmost in mainland Eurasia. The largest is Baishui glacier No. 1. Up to 90% of the annual precipitation there falls in summer, when warm moisture-rich air masses associated with the southwest monsoon reach the area from the Indian Ocean. The winter climate is influenced by air masses with a continental origin and by the southern branch of the westerlies. The snow that accumulates on Baishui glacier No. 1 includes marine aerosols associated with the summer monsoon, and dust brought in winter from central/west Asia, Africa or the Thar Desert area. Studies in May 2006 at two sites, one in the accumulation area (4900 m) and one in the ablation area (4750 m), revealed differences between the ionic composition of the snow that had accumulated in the 2005/06 winter and that of the snow which had been deposited during the preceding summer monsoon. Differences in the chemistry of the summer-accumulated snow at the two sites probably reflected local differences in ablation and elution rates, rather than differences in ion supplies. Differences in the chemistry of the winter-accumulated snow may reflect the influence of up- valley winds, which bring more crustal material to the lower site.

土地节约集约利用技术方法研究:现状、问题与趋势

Currently,intensive land use research have got many research fruits. But some problems about basic theory, evaluate scale and methods, control technology of economizing land have been existed. Based on the review on researches on intensive land use,the developing trend and keystone of intensive land use research which should be enhanced in the future have been discussed in this paper.It can be concluded following research contents: ① the basic theory of intensive land use. Relevant technology and criterion, pattern and policy should be reviewed in order to construct the theory system of intensive land use research. ② surveying and evaluation of intensive land use. It is urgent to propose the indices and contents of investigating and monitoring on intensive land use and to study on surveying methods and evaluation methods from different angles of view and the process of environment change in different modes of intensive land use. ③control technology of economizing land, including controlling indicators of major types of construction land, methodologies of land use planning and zoning, engineering technologies of intensive land use. ④restoration and reuse technologies on wasted land and degraded land, including information mining and evaluation, ecological restoration and reuse on wasted and degraded land, risk evaluation and ecology restoration on contaminated land, etc. ⑤criterions and standards of intensive land use, including investigation and evaluation criterion, controlling criterion of industry land, etc. The results and conclusions in this paper will provide scientific basis for accelerating the study of intensive land use in China.

Environment significance and hydrochemical characteristics of supra-permafrost water in the source region of the Yangtze River

This paper analyzed the environment significance and hydrochemical characteristics of the main ions on the supra-permafrost water from the view of space-time and different ablations. The study is conducted through collected 330 samples from June to September in 2016 and 2017 in the Source Region of the Yangtze River (SRYR). The results showed the pattern of ionic dominance based on mean value was following as: Cl- > Na+ > SO42- > Ca2+ > Mg2+ > K+ > NO3- > NO2- > NH4+ > F- > Li+. Cl- alone contributed 40.57%, and Cl-, Na+, SO42- and Ca2+ accounted for 94.06% of the total ionic concentrations. The spatial variation of ionic concentration was larger at the initial stage of ablation, and more stable in strong ablation and the end of the ablation stage. The area with elevation of 4500 m was the region where the control source of ions was more sensitive to the hydrochemical characteristics of supra-permafrost water in the study area. Through the analysis of the sources of ions, the anions and cations in supra-permafrost water in the study area were mainly controlled by crustal sources including evaporates rocks and carbonate rocks. The recharge effect of precipitation and snow-melt water only affected the concentration of Cl-, NH4+, NO3-, F-, Li+ and K+, but did not affect NO2-, SO42-, Mg2+ and Ca2+. The hydrochemical type of supra-permafrost water was Ca2+-SO42- in high elevation (>4800 m). However, the hydrochemical type of middle elevation (from 4400 m to 4700 m) was Na+-Cl-. The type of hydrochemistry at low altitude was more complex than at high and middle elevation. This study provides insights on the construction of hydrological models in the cold regions and scientific basis for water resources management in the Tibet Plateaus.