25 February 2017, Volume 39 Issue 1
    

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  • Responses of active layer thickness on the Qinghai-Tibet Plateau to climate change
    XU Xiaoming, WU Qingbai, ZHANG Zhongqiong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 1-8. https://doi.org/10.7522/j.issn.1000-0240.2017.0001
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    The change of active layer thickness has significant influence on the ecosystem, energy balance and carbon cycle between ground and atmosphere, therfore Stefan formula was used to simulate the distribution and spatial variation of active layer thickness on the Qinghai-Tibet Plateau from 1981 to 2010. It is found that the active layer thickness is 2.39 m in average in permafrost regions, which is the smallest in Qiangtang Basin and the largest in the marginal zones of permafrost regions. Active layer thickness is larger in the Qilian Mountains, the West Kunlun Mountains and the Nyainqentanglha Mountains. Owing to climate change, active layer thickness on the plateau has an increasing tendency; during the 30 years from 1981 to 2010, the active layer thickness had changed from -1.54 to 2.24 m, with a change rate of -5.90 to 10.13 cm·a-1 and an average rate of 1.29 cm·a-1. The change of active layer thickness is basically consistent with the change of mean annual air temperature, which indicate that climate change has a great impact on the active layer thickness.
  • Analysis of the relation between glacier volume change and area change in the Tianshan Mountains
    WANG Puyu, LI Zhongqin, LI Huilin, LI Kaiming, XU Chunhai
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 9-15. https://doi.org/10.7522/j.issn.1000-0240.2017.0002
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    Glacier volume change has significant influence on sea level, regional water resources, eco-environment and social economy. However, it is very difficult to carry out in-situ measurement. The main aim of this study is to make quantitative investigation on the scaling relation between glacier volume change and area change based on the ice volume estimation of nine glaciers in the Tianshan Mountains. Then, the scaling relation between glacier volume change and area change, which is suited for current climate condition and response process of glaciers, is established by using statistical method in order to estimate glacier volume change from glacier area change. It is found that there is a linear relation between glacier reserve change and glacier area change, with a determination coefficient between 0.67 and 0.70. The determination coefficient does not improve much as adding samples of glaciers in the other mountain areas. The reason may be that, on the one hand, there are errors in the glacier change monitoring and volume estimating, on the other hand, the sensitivity of glacier change to climate change, which depended on the glacier type, size and their regional differentia, is not the same. Therefore, in further study, it is necessary to focus on not only glacier volume estimation, but also on the glacier type and its regional differentia.
  • Responsivity of glacier to climate change in China
    CHEN Hongju, YANG Jianping, TAN Chunping
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 16-23. https://doi.org/10.7522/j.issn.1000-0240.2017.0003
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    Clarifying the responsivity of glacier to climate change and revealing the spatial variation of the responsivity are the basis for carrying out a quantitative research of glacier change and the quantization study of glacier change influence on the society economy. Using the summer temperature and precipitation records from 1958 through 2010 from 150 meteorological stations in the western regions of China and the first and second “Glacier Inventory of China”, climate change and glacier change were identified quantitatively with the change rates of glacierized area. The methods of referencing and comparison were used innovatively. The response of glacier to climate change was studied in West China by geographic information system (GIS) technology. According to equal interval classification method, the responsivity was classified into five classes:extremely low, low, medium, high and extremely high responsivities. The results showed that the degree and style of glacier response to climate change was various, which had positive response to summer temperature change and negative response to precipitation change. Moreover, glacier accumulation increase due to precipitation increase in the glacierized area is not sufficient to offset the ablation increase due to air temperature increase. Warming is the decisive factor for glacier retreat in West China. On the whole, glacier change had low response to summer temperature change, but had extremely high sensitivity on temperature change with high or extremely high response in some areas. Different types of glacier change have different degree of response to summer temperature change. The maritime glaciers had medium or high responsivity. However, extreme-continental glacier change had extremely low or low responsivity; continental glaciers had two polarized responsivity.
  • Remote sensing monitoring of the glacier change in the Gangrigabu Range, southeast Tibetan Plateau from 1980 through 2015
    WU Kunpeng, LIU Shiyin, BAO Weijia, WANG Rongjun
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 24-34. https://doi.org/10.7522/j.issn.1000-0240.2017.0004
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    Researches reveal that most glacier around the globe have retreated due to climate warming in recent decades. In this study, the change of glaciers in the Gangrigabu Range, southeast Tibetan Plateau, was analyzed using the 1:50 000 topographical maps based on the aerial photos taken in 1980 and the Landsat OLI images in 2015. The following conclusion can be drawn that most glaciers in the Gangrigabu Range were in retreat, where the glacierized area had decreased by 679.50 km2, or 24.91% (0.71%·a-1), and the average elevation of glacier terminal had uplifted 111 m. In the study area, there were 10 glaciers advancing, which had experienced a mean advance of 566.17 m, and other glaciers had retreated 823.49 m in average. Compared with glacier change in other mountains of China, one can see that the annual average area shrink ratio of glaciers was larger in the Gangrigabu Range, with a maximum annual average length retreat rate, which was one of the regions with strongest glacier shrinkage. There was a close relation between glacier retreat and climate change in the Gangrigabu Range. It is revealed from the records in three meteorological stations in the study area that the average temperature from May to September has increased significantly since 1980, but precipitation from May to September has insignificant change, resulting in glacier fast retreating.
  • Measurements of the surface features and the reflectance of Arctic sea ice during the initial phase of the melt season in Barrow
    AN Hongmin, DOU Tingfeng, CHE Tao, XIAO Cunde, DU Zhiheng
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 35-42. https://doi.org/10.7522/j.issn.1000-0240.2017.0005
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    In the initial phase of the melt season of the Arctic sea ice, the overlying snow melts dramatically and the melt ponds begin to form, resulting in complicated physical characteristics of sea ice surface. Due to lack of observational data, there are still large uncertainties in the study of sea ice changing during this period. In this study, the physical features and spectral reflectance on the surface of the sea ice in Elson Lagoon ocean area at Barrow, Arctic were observed in May 2015. The reflectances of surface snow cover, bare ice and melt ponds at the early ablation stage of sea ice were analyzed and the potential influence factors were also explored. The results showed that in the initial phase of the melt season, the heterogeneity of sea ice surface was significant with alternate distribution of snow cover, bare ice and melt ponds. In snow cover area, snow played a decisive role on sea ice reflectance. The observed reflectances at different snow depths (3~23cm) ranged between 0.53 and 0.85, positively correlated with snow depth. For the areas with same snow depth, higher water content of the bottom would lead to smaller surface reflectance. Observations also showed that sea ice reflectance decreased dramatically at the melt pond area, reaching 0.206 at the beginning formation period of the melt ponds, which was slightly lower than the reflectance of bare ice, 0.216. The reflectance would decrease with the development of the melt ponds and approach to that in open water when the depth of the melt ponds reached 10 cm.
  • Air temperature from May through August in northern Xinjiang reconstructed from multi-site tree-ring density
    CHEN Feng, YUAN Yujiang, WEI Wenshou, YU Shulong, SHANG Huaming, ZHANG Tongwen, ZHANG Ruibo, WANG Huiqin
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 43-53. https://doi.org/10.7522/j.issn.1000-0240.2017.0006
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    Tree-ring density from five sites in northern Xinjiang and the Tianshan Mountains was analyzed by using principal component analysis and arithmetic average method. It is found that the first principal component of density chronology accounted for 40.86% of the total variances of the five site density chronologies, and highly correlated with the arithmetic average of the five site density chronologies. The arithmetic average of the five site density chronologies was highly positively correlated with the May-August mean temperature averaged over the thirty-three meteorological stations in northern Xinjiang and the Tianshan Mountains. The climate/tree-growth model accounted for 44.5% of the temperature variance from 1960 to 2008. There were six warm phases during 1656-1664, 1667-1692, 1711-1734, 1804-1832, 1855-1956 and 2000-2008. There were several severe cold phases coinciding with major volcanic eruptions. Some temperature variations also correspond to the variations in solar activity. Low-frequency change of the reconstructed temperature had correlated positively with Northern Hemisphere temperatures. The reconstructed temperature was significantly correlated with sea-surface temperature (SST) in the tropical Atlantic Ocean (positive), the North Pacific Ocean (positive) and the North Atlantic Ocean (positive). The spatial correlation patterns between the reconstructed temperature and SSTs of the Atlantic and Pacific Oceans, cloud cover, and volcanic eruptions suggested that there was a connection between regional temperature variation and the high-mid latitude northern atmospheric circulation (westerlies).
  • Characteristics of CO2 flux over the alpine wetland in the Tibetan Plateau and its control factors
    ZHANG Haihong, LI Lin, ZHOU Bingrong, XIAO Hongbin
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 54-60. https://doi.org/10.7522/j.issn.1000-0240.2017.0007
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    Using the data observed by eddy-covariance flux in Longbao wetland, Yushu, in 2015, characteristics of CO2 flux and its control factors were analyzed. The results show that daily change of CO2 flux in Longbao wetland was inverted unimodal and was negative in daylight and positive at night. Daily range of CO2 flux was maximum in July and minimum in January. From April to September there was a carbon sink in the alpine wetland ecosystem and a carbon source in other months. Annual CO2 net absorption was 465 g·m-2. CO2 flux decreased with photosynthetically active radiation increase in daylight. CO2 emission was positively correlated with soil temperature and daily rangeability of air temperature. Alpine wetland soil moisture effected on CO2 flux very weak. CO2 emission increased in short order after rain event. CO2 flux strongly correlated with photosynthetically active radiation, following by daily rangeability of air temperature and soil temperature. CO2 flux weakly correlated with soil moisture.
  • Assessment and analysis of the freeze-thaw erosion sensitivity on the Tibetan Plateau
    WANG Liyan, XIAO Yi, JIANG Ling, OUYANG Zhiyun
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 61-69. https://doi.org/10.7522/j.issn.1000-0240.2017.0008
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    Following the water erosion and wind erosion, freeze-thaw erosion is the third strong soil erosion in China. The Tibetan Plateau is a severe freeze-thaw erosion area owing to its high altitude, strong radiation and low temperature. Five indices are chosen to assess freeze-thaw erosion. They are annual range of temperature, annual precipitation, slope, slope aspect and vegetation coverage. The results show:(1) The distribution of freeze-thaw erosion is very extensive in the Tibetan Plateau, with the freeze-thaw erosion area of 149.02×104 km2, accounting for 62.20% of the total area of the Tibetan Plateau. Freeze-thaw erosion sensitive area is 56.80×104 km2, among which moderate and more sensitive area is 27.39×104 km2, accounting for 48.22% of the total freeze-thaw erosion sensitive area in the Tibetan Plateau; (2) The regional differentiation of freeze-thaw erosion sensitivity is obvious. Different intensities of freeze-thaw erosion sensitivity appear in different regions. The sensitivity is heavy in south and southeast of the plateau, Karakoram Mountains, Qilian Mountains, and Hengduan Mountains.
  • Accuracy verification of the Tibetan Plateau Permafrost Map based on MODIS LST product
    SHI Yaya, YANG Chengsong, CHE Tao
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 70-78. https://doi.org/10.7522/j.issn.1000-0240.2017.0009
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    The use of remote sensing data can greatly improve the efficiency of the Tibetan Plateau permafrost classification and mapping, and less require the observation in cold terrain, which avoid the huge consumption of manpower and material resources. To assess the accuracy of the Permafrost Map based on MODIS LST products, in this study, the 1:4 000 000 Tibetan Plateau Permafrost Map, the 1:3 000 000 Tibetan Plateau Permafrost Map and the Tibetan Plateau Permafrost Map based on MODIS LST product were validated comprehensively in the Wenquan area in the east of the plateau and the West Kunlun Mountains in the northwest of Tibetan Plateau. The results show that the Tibetan Plateau Permafrost Mapping based on MODIS LST product can better reflect the distribution and features of the permafrost. At the same time, there are many differences between the permafrost and seasonal frozen soil edge regions, mainly due to the mapping time difference, local factors, vegetation, snow cover and other multiple factors.
  • Settlement analysis of embankment-bridge transition section in the permafrost regions of Qinghai-Tibet Railway
    WANG Jinchang, WU Qingbai
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 79-85. https://doi.org/10.7522/j.issn.1000-0240.2017.0010
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    Since the beginning of the Qinghai-Tibet Railway operation, the train has safely run for nearly ten years owing to better stability of permafrost engineering. However, it is also inevitable to appear some damages to the railway. Survey results in-situ show that serious thaw settlement has be found in the transition section between embankment and bridge. Based on the thaw settlement characteristics and analysis of engineering geological conditions, it is found that thermal erosion of subsurface and supra permafrost water lead artificial permafrost table lower and permafrost with high ice content thawing, resulting in extensive thaw settlement of embankment. To transact this damage, measures of keeping cool of permafrost should be taken to strengthen the freeze of roadbed. While, engineering conditions in subsurface water and waterproofing and drainage should be improved to decrease thaw settlement caused by thermal erosion of subsurface and supra permafrost water. This study provides a scientific basis for stabilizing and maintaining the transition section between embankment and bridge.
  • Direct shear tests of freezing strength at the interface between cast-in-situ concrete and frozen soil
    JI Yanjun, JIA Kun, YU Qihao, JIN Huijun, GUO Lei, LUO Xiaoxiao
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 86-91. https://doi.org/10.7522/j.issn.1000-0240.2017.0011
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    Previous experimental study of interface strength between concrete pile and frozen soil has focused more on the mechanical properties of the interface between precast concrete block or specimen and frozen soil with less information about direct shear test of freezing strength between cast-in-situ concrete and frozen soil. Based on a new specimen preparation method, a series of laboratory direct shear tests of the interface between cast-in-situ and frozen soil were performed. The results show that because of difference in thermal parameters of concrete, the interface between cast-in-situ concrete and frozen soil appears irregular model. Freezing strength of rough interface will increase by 71.9% as compared with that of smooth interface. Stress concentration occurs on the rough interface, resulting in stress intermittently increasing and jumping in the shear failure process. With the increase of roughness at the interface, φ contribution increase more than c contribution increase by degree. Thus φ can play more important role in the growth of freezing strength. When water cement ratio increases from 0.4 to 0.6, with the thermal conductivity of concrete decreasing, the interface becomes smoother and the freezing strength will decrease; when water content increases from 15% to 30%, freezing strength will increase first and then decrease; when water content increases to 40%, freezing strength will decrease. Thus, it is recommended that 0.4~0.5 is a reasonable water cement ratio, according to this study.
  • Research state of deformation characteristics of frozen soil under cyclic loading and problems in frozen soil excavation
    LI Xiaolin, WANG Hongjian, ZOU Shaojun, MA Haocheng, NIU Yonghong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 92-101. https://doi.org/10.7522/j.issn.1000-0240.2017.0012
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    The deformation characteristics of frozen soil under cyclic loading are discussed, with the research achievements of predecessors on the deformation properties of frozen soil. The state of research and main conclusions on the impacts of the main factors, such as soil type, moisture content, ice content, temperature, confining pressure, amplitude and frequency of cyclic loading, are deeply studied. The importance of mechanical excavation method of frozen soil is stressed after a brief discussion of the present of the excavation practices in frozen soil. At last, some suggestions are presented for further studies on the deformation characteristics of frozen soil, aiming at improving the efficiency of frozen soil excavation.
  • Review of the coupled hydro-thermo-mechanical interaction of frozen soil
    LU Jianguo, ZHANG Mingyi, ZHANG Xiyin, PEI Wansheng
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 102-111. https://doi.org/10.7522/j.issn.1000-0240.2017.0013
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    Research on the coupled hydro-thermo-mechanical interaction of frozen soil is important for solving engineering problems in cold regions. In this paper, a general overview of the coupled hydro-thermo-mechanical of frozen soil is made. First, the basic theory of the coupled hydro-thermo-mechanical of frozen soil is summarized, it is found that the current hypothesis of the driving force of moisture transfer is limited to reveal the moisture transfer characteristics in freezing soil and the formation mechanisms and criterion of the segregated ice are still needed further study. Then, the existing coupled hydro-thermo-mechanical models are classified and evaluated. It is found that the fluid dynamics model is able to describe moisture-heat transfer well but have not consider the non-continuous ice lens; the rigid ice model has considered the coupled moisture-heat transfer in the frozen fringe but there are multitudinous parameters applied; the thermodynamic model is able to describe the coupled hydro-thermo-mechanical phenomena and pore suction from the microscopic view but also contains a lot of parameters. These coupled hydro-thermo-mechanical models reveal heat, moisture, stress and their coupling relations from different aspects, but the limitations are also obvious. Meanwhile, the pre-melted films theory can be introduced to explain the energy, driving force and the migration rate of the moisture in the coupled hydro-thermo-mechanical model of frozen soil. From the above discussions, it is proposed and suggested that coupled hydro-thermo-mechanical study of frozen soil should be taken, including establishing a conceptual model for steady and transient state, undertaking the dynamic study of the physical parameters of the frozen soils, studying the interaction among the moisture, heat and stress in freezing-thawing process of unsaturated soil, promoting the application research of the pre-melted films theory in the large-scale phenomenon, the land surface processes and hydro-thermal boundary conditions.
  • Interactions between the pipeline and soils in permafrost regions:a review
    HUANG Long, SHENG Yu, HU Xiaoying, WANG Shengting
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 112-122. https://doi.org/10.7522/j.issn.1000-0240.2017.0014
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    Pipeline is one of the most economical and effective tool for long distance transportation of gas and oil. The pipeline may be subject to bending deformation and possible failures caused by the frost heaving and thawing through permafrost regions. Therefore, the interactions between pipe and soils have been one of the most important factors for pipe design and operation to consider in permafrost regions. In this paper, the development and progress in design theory of main pipeline projects in permafrost regions(e.g., Norman Wells Pipeline, Far East Pipeline of Russian, Alyeska Pipeline, and Pipelines in China) are briefly reviewed, the latest achievements and progresses in indoor and outdoor experiments and analysis theory, together with the method of numerical simulations for studying the interaction between the pipeline and soil are summarized. In the end, further research and prospect on the pipe-soil interactions in permafrost regions are proposed.
  • Variation of the runoff in the upper and middle reaches of the main Heihe River and its causes
    CHENG Jianzhong, LU Zhixiang, ZOU Songbing, CHENG Wenjia
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 123-129. https://doi.org/10.7522/j.issn.1000-0240.2017.0015
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    The interannual variability, annual distribution and variation of the runoff in the upper and middle reaches of the main Heihe River and their reasons are analyzed based on the measured hydrological and meteorological data, together with the groundwater level data in in the midstream. The results show that the runoff in the upper reaches of the river has slightly increased since 1945 as a whole, and the month with the maximum runoff has shifted from July to August since the beginning of the 21st century, which was mainly controlled by the precipitation. The runoffs at Gaoya and Zhengyixia Stations have increased slightly since 1977 with the rates of 1.7 million m3 and 10.2 million m3 per year, respectively. The water consumption in the section from Yingluoxia to Gaoya have increased at the rate of 8.5 million m3 per year due to the social and economic development; the amount of the irrigation return water and groundwater recharging to the river have been almost the same as the irrigation water diversion and other water consumption in the section from Gaoya to Zhengyixia. Excessive exploitation of groundwater have slowed down water consumption pressure in Heihe River basin to a certain extent, but it was bad to the sustainable utilization of water resources. This results will be helpful for scientific allocation and reasonable regulation of water resources in the Heihe River basin.
  • Effects of seasonal grazing on vegetation water consumption and water utilization efficiency in alpine meadow of the source regions of the Yellow River
    HE Huidan, YANG Yongsheng, ZHU Jingbin, LI Hongqin, WEI Yaxi, LI Yingnian
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 130-139. https://doi.org/10.7522/j.issn.1000-0240.2017.0016
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    Research of seasonal grazing impact on vegetation water consumption and water utilization efficiency is one of the important contents of how to improve the capacity of water conservation. Taking the alpine meadow under the condition of seasonal grazing and natural grazing in Maqin, Qinghai Province as the research object, the dynamic changes of vegetation water consumption, water surplus and deficit, vegetation productivity and water utilization efficiency and their relations with environmental factors were analyzed. The results show that in vegetation growing season (from May to September), vegetation water consumption first increase in May and then drop in the seasonal grazing plots and natural grazing plots. The maximum water consumption is in July, up to 160.94 mm, and 145.96 mm, respectively. The total vegetation water consumption of seasonal grazing plots (395.52 mm), 13.61% more than that of natural grazing plots (348.14 mm). On average, from May to September, water surplus amount of seasonal grazing plots and natural grazing plots is 13.58 mm and 70.96 mm, respectively. But they all have a slight deficit in August. The vegetation water consumptions of seasonal grazing plots and natural grazing plots are all weak positively correlated with precipitation, and have nothing to do with soil moisture storage. Seasonal grazing can increase the amount of vegetation production. The aboveground and belowground net primary productions and the total net primary production are 32.54 g·m-2, 5.96 g·m-2, and 38.50 g·m-2, respectively, larger than those in natural grazing plots. The water utilization efficiency of aboveground net primary production in seasonal grazing plots is higher than that in natural grazing plots. Besides, belowground net primary production and total net primary production in seasonal grazing plots are lower than those in natural grazing plots by 13.06% and 9.97%, respectively, showing that seasonal grazing can improve the vegetation production and water consumption, but the impact on water utilization efficiency depends on a lot of indexes.
  • Analysis of the characteristics of runoff yield and confluence in the Laohugou basin, Qilian Mountains
    ZHANG Xueyan, QIN Xiang, WU Jinkui, ZHANG Xiaopeng
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 140-147. https://doi.org/10.7522/j.issn.1000-0240.2017.0017
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    In order to study the characteristics of runoff yield and confluence in Laohugou basin, the hydrological characteristics are analyzed in this paper based on the measurements in the Laohugou Glacier No.12 from April to October, 2009. The results show that from May to September, monthly runoff accounted for 7%, 26%, 33%, 19%, 14%, respectively, of the annual total. Precipitation contributed to the annual runoff about 22%. Glacier meltwater and groundwater contributed the annual runoff about 78%. The runoff during the daytime was higher than that in the night except May. The most part of the Laohugou glacier surface was bare ice, with a small amount of little lakes, resulting in minor water storage ability. On average, the peak and valley of runoff lagged the peak and valley of temperature for 7.0 h, 3.5 h, 2.5 h, 2.5 h, 4.5 h, respectively, from May to September. Glacier drainage system also experienced a slow-fast-slow process.
  • Response of glacier runoff to climate change in the Laohugou basin, Qilian Mountains
    ZHANG Xiaopeng, QIN Xiang, WU Jinkui, CHEN Jizu, WANG Qiang, DU Wentao, LIU Yushuo
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 148-155. https://doi.org/10.7522/j.issn.1000-0240.2017.0018
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    For quantitatively researching the response of Laohugou basin's runoff to climate change, using meteorological and runoff data of Laohugou basin in the strong ablation period of 1959 and 2014, the changes of air temperature, precipitation, evaporation, glacial ablation, runoff in the strong ablation month (July) of 1959 and 2014 in the whole basin were analyzed. The melting process and runoff response to climate change in the Laohugou basin also discussed. The results showed that in July, 2014, the climate change led to runoff increase 159 mm, accounting for 49.67%, higher than that in 1959; the monthly mean air temperature in July had increased 0.38℃, and the monthly minimum temperature had increased 1.34℃ as compared with that in July, 1959. Precipitation was the same nearly in July, 1959 and July, 2014. There was a negative correlation between precipitation and runoff; there was small change in evaporation; the ratio of mixed state precipitation had decreased by 23.01%, resulting in increasing the proportion of precipitation translating directly into runoff. The cumulative positive temperature had played a decisive role. The cumulative positive temperature in July, 2014 was 11.71℃·d higher than that in July, 1959, mainly due to the temperature of 2-4℃ increasing, resulting in cumulative positive temperature increasing, which intensified the supply of meltwater to runoff.
  • Hydrograph separation of melt-water:review and expectation
    ZHOU Minpei, YU Zhongbo, LI Xiangying, GAO Yiyan
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 156-164. https://doi.org/10.7522/j.issn.1000-0240.2017.0019
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    The global climate continues to warm, resulting in the sustaining increase of the glacier-snow melt water and permafrost degradation in the alpine zone. The glacier-snow melt water increased significantly. Different hydrograph separation methods of melt-water can quantify the contribution of snow and ice melt water to the river and reflect the changes of snow and ice in the alpine area and their response to climate warming. In this paper, different hydrograph separation methods and their advantages and disadvantages are reviewed, with an emphasis on the calculation methods of isotopic/chemical hydrograph separation and the selection of tracers. The results of hydrograph separation of different watersheds are compared and analyzed, and the main factors influencing the change of melt-water runoff are discussed in detail. Aimed at the idealized hypothesis of the isotope hydrograph separation, an extended study of quantified uncertainty is proposed. Finally, the development of isotope hydrograph separation is prospected, with the improvement of high frequency sampling technique.
  • Study of the difference in climate response of Dahurian Larch and Pinus sylvestris growth in the north Great Higgnan Mountains of permafrost regions, Northeast China
    ZHANG Xuanwen, YANG Li, LIU Xiaohong, ZHANG Qiuliang, WANG Wenzhi, ZENG Xiaomin, WU Guoju
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 165-174. https://doi.org/10.7522/j.issn.1000-0240.2017.0020
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    Based on the Dahurian Larch and Pinus sylvestris tree-ring samples taken from Genhe, Hanma and Huzhong permafrost regions in the north Great Higgnan Mountains, five tree-ring width chronologies were established, and then the basal area increment (BAI) was calculated for the five sites. The response analysis showed that temperature was the dominant factor affecting the tree growth in these regions, with distinct difference between the two species. BAI of Dahurian Larch was significantly and negatively correlated with the monthly average temperature in March. BAI of Pinus sylvestris was significantly and negatively correlated with the monthly averaged temperature from previous December to current April. The climate limiting factor on the radial growth of Dahurian Larch had transformed from a significant negatively correlation with SPEI index in Janurary from 1957 to 1990 into a significant correlation with SPEI index from Janurary to April and temperature in March from 1991 to 2013, and the climate limiting factor for Pinus sylvestris had changed from a significant negative correlation with February and August temperatures from 1957 to 1990 to a significant correlation with precipitation in July and SPEI index from June to July from 1991 to 2013. These results indicated that the two species responding to climate change, especially, to temperature change, was different under the background of global warming, even the climate limiting factor on radial growth would change in different periods for the same species.
  • Effect of freezing and thawing cycles on soil microbial activity and organic carbon density in forest swamp wetland with various drainage afforestation years
    GUO Dongnan, ZANG Shuying, ZHAO Guangying
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 175-184. https://doi.org/10.7522/j.issn.1000-0240.2017.0021
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    Taking the wetland soil in the Xiaoxing'an Mountains as the object, changing trends of soil microbial biomass, enzyme activity and organic carbon density in forest swamp wetland with various drainage afforestation years under different freezing and thawing cycles were analyzed. The relation between soil microbial activity and organic carbon density was investigated in order to reveal the soil carbon cycle process in alpine-cold and high latitude regions during the freezing-thawing season. Freezing-thawing cycles has impacted significantly on microbial biomass carbon and nitrogen in soil (P<0.05). After nine freezing-thawing cycles, microbial biomass carbon and nitrogen in soil decreased obviously, and the shorter the drainage time, the more the decrease in microbial biomass carbon and nitrogen in soil, as showing in three different drainage afforestation wetlands. These reveal that repeated freezing and thawing would result in deeper degree of microbial biomass reduction for a long time. Before and after the freezing and thawing, soil invertase and amylase activities showed a declining trend. Compared to -5 to 5℃, -25 to 5℃ repetitive freezing-thawing treatment could decrease enzyme activity, which suggested that the larger range of freezing and thawing temperature would accelerate the activity reducing. With the change in number of freezing and thawing cycles and temperature, soil organic carbon density in the four wetlands was stable basically, but still remained positive correlations with microbial biomass and enzyme activity. Therefore, studying the regulating process of soil microbial activity is useful to understand, directly or indirectly, the change trend and verify the essential response mechanism of soil organic carbon density.
  • Variation of vegetation net primary productivity in Hunshandak Sandyland during 2000-2013
    YUAN Zhihui, CHI Yongfeng, LEI Jun, BAO Gang, BAO Yuhai, SA Chula, YONG Mei
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 185-199. https://doi.org/10.7522/j.issn.1000-0240.2017.0022
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    Using remote sensing data and ground meteorological station data, sand land net primary productivity (NPP) during the growing season from 2000 to 2013 in Hunshandak Sandyland were estimated using CASA model, and the spatial-temporal characteristics of NPP were analyzed. Impacts of climatic factors and human activities on the sand land NPP were primarily revealed by statistical analysis. The results showed that the sand land NPP had increased by fluctuation during growing season in Hunshandak Sandyland from 2000 to 2013, with an average annual NPP of 239.8 gC·m-2·a-1 in the study area. The area of high NPP (NPP>150 gC·m-2·a-1) had increased while that of low NPP (NPP<150 gC·m-2·a-1) had decreased. In spatial pattern, the NPP in northern, central and southern fringe regions of the study area had increased, but no obvious trends had been observed in eastern and some of the western parts. As a whole, the annual NPP had depended more frequently on precipitation fluctuation. The correlation coefficient between NPP and precipitation was 0.86, indicating precipitation was the dominant driving force in vegetation dynamics. The correlation coefficient between NPP and temperature was -0.42. While temperature, sown area of feeding, the total livestock at the year-end and the number of sheep in Hunshandak Sandyland showed a decrease trend, the sand land NPP had increased rapidly and remarkably.
  • Impact of human factors on environment in a Silk Road economic belt node city
    YU Wenbao, SONG Xiaoyu, JIAN Fuhui
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 200-206. https://doi.org/10.7522/j.issn.1000-0240.2017.0023
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    To construct “OBOR” has been upgraded to a national strategy, Northwest China will become the frontline of reform and opening. With the introduction of STIRPAT model, analyzing the impact of human factors on the environment and predicting the future carbon emissions in a Silk Road economic belt node city show that the human factors are the significant driving forces for carbon emissions, with a goodness of 95.2%; the elastic coefficients of energy consumption intensity, affluence and population are 0.511, 0.285 and 0.222, respectively. The carbon emission rises steadily in the business as usual scenario, however, in the policy scenario and low carbon scenario there is a inflection point with a peak in 2025-2033. The peak of low carbon scenario arrived eight years earlier than that of policy scenario, reducing the peak amount of 407 900 tons. Finally, suggestions are made for policy makers based on the analysis results, that is to control the population size, to optimize the industrial structure and to strengthen pollution control.
  • Regional comparison of water footprint in China based on the multi-regional input-output analysis:in the analytical level of economic regions
    WU Zhaodan, WU Zhaolei, ZHANG Changzheng
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 207-219. https://doi.org/10.7522/j.issn.1000-0240.2017.0024
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    Based on the analytical level of economic regions, applying the multi-regional input-output analysis, Theil index spatial difference decomposition method and pseudo-Gini coefficient difference causes decomposition method, the water footprint similarities, differences and the difference genesis are unearthed in the scale of both the inter-economic region and the inter-province in each economic regions, from three aspects of total amount, department structure and relevant index, accompanied by the regions where water use is necessary to adjust in the water security system with Chinese characteristics. The results show that:(1) The contribution of inter-economic region divergence and the inter-province difference in each economic region are almost the same to the overall spatial variation of water footprint in China. (2) The water footprint in the northwest, middle and southwest regions are higher than that in any other economic regions. Both the inter-region divergence of per capita water footprint in the agriculture, forestry, animal husbandry and fishery and that of the population are the main cause of water footprint difference among economic regions. The water footprint of primary industry in the north coast region and northwest region and that of food manufacturing and tobacco processing industries in other regions are, respectively, the main component of the water footprint in the corresponding region. (3) There are similarities and differences among the most contributors of the inter-province water footprint difference in each economic region. While most contributors of them come from the inter-province divergence of the corresponding department per capita water footprint. Some similarity and differences are also shown in the structures of the departments in provincial water footprint. (4) It is greatly necessary to adjust water use in northeast region (especially Heilongjiang), Beijing-Tianjin region (especially Tianjin), Shandong, Shanghai, Hainan, Ningxia, Chongqing and Shanxi, while it is less necessary to adjust water use in the northern coastal region (except Shandong), the eastern costal region (except Shanghai), the northwest region (except Ningxia), followed by Yunnan and Jiangxi.
  • Study of the social economic development impacting the desertificationin southern Xinjiang
    Obul Talip, Alimujiang Kasimu
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2017, 39(1): 220-228. https://doi.org/10.7522/j.issn.1000-0240.2017.0025
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    Ecosystem degradation intensifies the desertification in southern Xinjiang. In this paper, desertification in southern Xinjiang is analyzed by using the NDVI data through the support of ENVI software. The result shows that the area of desertification in southern Xinjiang had increased 11 percent from 1952 through 1983. Among them, the area of heavy desertification had increased approximately 14.21%, while the area of moderate and mild desertification had increased 7%~8%. The area of desertification had kept stationary from 1983 through 1993. At the beginning of the 21st century, the area of desertification reached 96.11×103 km2, which was calculated from the remote sensing data interpretation in 2000. It was accounting for 90.41% of the total land area, of which the area of heavy desertification and moderate-mild desertification were, respectively, 157.6×103 km2and 74.2×103 km2. The area of desertification reached 953.1×103 km2 in 2014, which had shrunk 1.24% as compared with that in 2000, while heavy moderate-mild desertification area had changed constantly. According to the deeply observing and searching of predecessors, the change of desertification should be ascribe to human activities and natural factors.
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