31 August 2021, Volume 43 Issue 4
    

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  • Lijun DUAN, Hongyan SHEN, Di YU, Youxuan MA, Wenrong BAI, Wanzhi LI
    Journal of Glaciology and Geocryology. 2021, 43(4): 939-947. https://doi.org/10.7522/j.issn.1000-0240.2021.0050
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    Based on the precipitation data on the Tibetan Plateau and the monthly reanalysis data of NCEP during 1961—2017, the water vapor transport characteristics of the Tibetan Plateau during rainy season was discussed. The results are as follows: the average precipitation of the Tibetan Plateau during the rainy season (May to September) had a significant inter-annual change; there is dramatically difference between the southern and northern Tibetan Plateau in the first EOF mode, and the second EOF mode had the same anormaly in whole area. Climate moisture transport path on the Tibetan Plateau during rainy season is westerly wind from the Arabian Sea is divided into three steam delivery streams near the Bay of Bengal: one part goes north, some of them shifted to southerly winds near the South China Sea, some of them transferred to the westerly wind were blocked by the plateau topography. In the strong years of precipitation during rainy season, the main body of the plateau is characterized by northern convergence and southern divergence. In the weak years, the southerly water vapor flow from the Arabian Sea changes to an easterly water current near 25° N, a strong water vapor convergence center is formed at the southern edge of the plateau. During the rainy season, the water vapor budget at each boundary of the plateau is as follows: the west, south and east boundaries are dominated by water vapor input, only the north boundary is the water vapor output, and the south boundary is the largest water vapor input, followed by the west boundary.

  • Jinhua HU, Zheng LU, Jinhui TONG, Xiaoyan LI, Shaomin LIU, Xiaofan YANG
    Journal of Glaciology and Geocryology. 2021, 43(4): 948-963. https://doi.org/10.7522/j.issn.1000-0240.2021.0054
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    Cold regions, which supply freshwater to downstream communities, have been significantly disturbed by anthropogenic climate change that is pronounced to continue in future. As unique and critical elements of the cold regions, frozen soil plays a vital role in cold region hydrology. Although frozen soil is considered relatively impermeable to groundwater flow, the freezing and thawing of the frozen soils under seasonal and climate change may influence the hydrologic components such as surface water infiltration, groundwater recharge, and hydrogeologic connectivity that are important for water resources. Under the pronounced climate warming, increased soil temperature expedites the thawing of frozen soil in cold regions. Therefore, understanding the complex thermo-hydrologic processes in frozen soils is one of key issues in studying cold region hydrology. However, due to the harsh environment, it is difficult to conduct hydrometeorological and geophysical field observations yet collect gap-free, high-resolution datasets. With the recent development of computational methods and resources and based on the observational data in recent decades, it is essential to enable modeling and simulation of the thermo-hydrologic processes in frozen soils to study cold region hydrology. The thermo-hydrologic processes in frozen soils is fundamentally interpreted into multi-phase flow and heat transfer in porous media with phase change. The current challenges in simulating such processes, especially in cold regions include but not limited to the interactions among liquid water, vapor, ice and soil grains and the phase change between ice and liquid water, which introduce high non-linearities and uncertainties in the processes. However, traditional distributed or hydrogeological models were limited in terms of resolution, accessibility and capability of solving the coupled thermo-hydrologic processes with high fidelity. To account for these feedbacks as far as possible, a physically-based, massively-parallel, fine-resolution and fully-saturated cryo-hydrogeological model was in-house developed in OpenFOAM?http://www.openfoam.com), an open-source computational fluid dynamics (CFD) solver, which has been widely used in groundwater modeling and computational hydrology. The cryo-hydrogeological model, named darcyTHFOAM, was formulated by mass conservation, Darcy’s law, energy conservation and soil freezing function. To ensure the convenience and joy for users, an interface-based software was developed correspondingly using Python 3.5 (www.python.org) and designed with QT Designer (www.qt.io) in Linux environment. In general, rigorous validation and benchmarking of the numerical models are prerequisites and critical for their validation and applications. Hence, a series of benchmarking simulations under fully-saturated condition were performed to validate the current model, including the classical analytical solution of Stefan’s equation, two community-recognized benchmark cases (under thawing) using synthetic porous media samples in the Interfrost Project (wiki.lsce.ipsl.fr/interfrost) and laboratory freezing experiment with a 25 cm-long soil column. Simulated results include the evolution of temperature, liquid water content and ice content. Frozen depth, temperature profiles at fixed points or lines, the minimum of the temperature field were selected for quantitative comparisons. Simulated results were in excellent agreements with those obtained from the analytical solution, other cryo-hydrogeological models and experimental data, respectively, which demonstrated the reliability and accuracy of the current model. The study revealed that the proposed model is capable of simulating coupled thermo-hydrologic processes under fully-saturated condition in cold regions with high spatial resolutions and efficiency. Overall, the in-house developed cryo-hydrogeological model is expected to serve as a powerful tool for studying subsurface hydrology in cold regions. Further code developments involve coupling the surface processes, especially snow, and transport processes (e.g. contaminants) for studying groundwater-surface water interactions and hydro-biogeochemical processes in cold regions.

  • Shibo LIU, Lin ZHAO, Lingxiao WANG, Defu ZOU, Huayun ZHOU, Changwei XIE, Yongping QIAO, Guangyang YUE, Jianzong SHI
    Journal of Glaciology and Geocryology. 2021, 43(4): 964-975. https://doi.org/10.7522/j.issn.1000-0240.2021.0033
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    As an emerging space technology in geodesy, synthetic aperture radar interferometry (InSAR) has the advantages of all-day, high-precision, large range and fast speed. It has a great potential for application in surface deformation measurement, and is increasingly used in the monitoring of permafrost areas. In this paper, the principle of permafrost deformation and the application of InSAR to monitor permafrost deformation are reviewed. The results show that the interannual deformation of the permafrost is mainly settlement in the context of climate warming, and the amount of underground ice near the upper limit of permafrost is the main factor affecting the interannual variation. Soil moisture content within the active layer affects the magnitude of the seasonal deformation variables. There are large differences in interannual and seasonal surface deformation variables for different types of permafrost areas. It was also shown that the applicability of SAR products at different wavelengths varies for different types of permafrost zones, and that subsurface features have a greater influence on the magnitude of deformation obtained by InSAR data, while the L-band SAR data are more effective in the areas with better vegetation cover. Owing to the decoherence problem of InSAR processing and the lack of validation and calibration data for long-term, multi-type, high-frequency permafrost deformation monitoring, it is of great practical and scientific significance to establish surface deformation inversion algorithms for different permafrost areas and to construct surface deformation data sets with high precision spatial and temporal resolution.

  • Huaqiu ZHAO, Xin WANG, Xuanru ZHAO, Wanqin GUO, Shiyin LIU, Junfeng WEI, Yong ZHANG
    Journal of Glaciology and Geocryology. 2021, 43(4): 976-986. https://doi.org/10.7522/j.issn.1000-0240.2021.0055
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    For the regional and global natural environment and economic and social development,it is of great significance to investigate the distribution and changes of glacier. In this paper, the boundary of the existing glaciers in China was achieved by manually visual interpretation guided by the methodology of the Second Chinese Glacier Inventory based on 315 Landsat 8 OLI remote sensing images, global watershed data and Google Earth in 2018. The state and area changes of glacier were examined during 2008—2018 compared to glacier boundary from the Second Chinese Glacier Inventory. The results show that there are 53 238 glaciers with a total area of (47 174.21±19.93) km2 in China currently, 72% of the glaciers in China are less than 0.5 km2, and the area of glaciers with a scale of 1 to 32 km2 accounts for 60% of the total area of Chinese glaciers. From 2008 to 2018, the total area of glaciers in China has decreased by 1 393.97 km2, and the area change rate was -0.43%?a-1. The area change rate of glacier shows obvious spatial heterogeneity. The fastest rate of glacier area retreat is the Gangdisê Mountains, reaching -1.07%?a-1; the slowest is the Qiangtang Plateau, with -0.05%?a-1. In terms of slope, the difference in change rate of glacier area between various mountains is relatively obvious. During 2008—2018, more than 70% of the mountains are located in the east and southeast with a fast average retreat ratio, which is -5.0%, and the retreat of glaciers in the north direction is relatively slow, with a retreat ratio of -3.8% during the same period. Differences in temperature and precipitation change rates, as well as differences in altitude, slope and aspect, affect glacier changes in China together.

  • Xin LIU, Xubing ZHANG, Yao WANG
    Journal of Glaciology and Geocryology. 2021, 43(4): 987-998. https://doi.org/10.7522/j.issn.1000-0240.2021.0057
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    Landsat-8 has great advantages in retrieving Arctic glacier surface velocities on a large scale due to its 15 m pixel scale resolution and 12-bit radiometric quantization of OLI band 8, with moderate repetition interval, high image acquisition rate, and high image quality. Based on Landsat-8 panchromatic band images on 2017/2018 of five typical Arctic regions—Greenland, Svalbard, Severnaya Zemlya, Franz Josef Land, and Devon Islands, we have retrieved surface velocities of marine-terminating glaciers during the ablation season using feature tracking method. Combined with MEaSUREs velocity data, we have analyzed the velocity spatial characteristics of total 198 marine-terminating glaciers in Arctic, and reflected the possible forces resulting in the spatial differentiation of velocity distribution. Also, we have analyzed the temporal and spatial velocity characteristics of Kangerlussuaq Glacier on the east coast of Greenland between March and October in 2018. Research shows that Arctic glaciers with front velocities of 5~10 m·d-1 or 10~20 m·d-1 mainly lying on the east and west coast of Greenland, and the highest speed reaches 31.79 m·d-1. Greenland internal velocity diversity is reflected in that average velocity among north coast is the slowest (1.99 m·d-1), while east coast (6.18 m·d-1) is higher than west coast (4.17 m·d-1). The spatial differences of glacier velocity may be attributed to glacier scale, bedrock terrain, ice-sea interaction, ice sheet ablation condition or other factors, and the influencing mechanism can be very complicated and intricate. Besides, between April and September in 2018, ice front speed of Kangerlussuaq Glacier is about 21.02~22.87 m·d-1 and the average glacier center streamline velocity is about 10.02~11.39 m·d-1. The peak velocity of Kangerlussuaq Glacier appears in June-July and September-October, and the trough appears in August-September, which is mainly due to the glacial meltwater lubrication and glacier mass balance.

  • Wanpin HU, Cunde XIAO, Aihong XIE, Yongping SHEN, Huajin LEI
    Journal of Glaciology and Geocryology. 2021, 43(4): 999-1008. https://doi.org/10.7522/j.issn.1000-0240.2021.0067
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    The Irtysh River originates from the southern slope of the Altai Mountains in Xinjiang, China, and is the only river in China that flows into the Arctic Ocean. With the “Polar Silk Road” proposed by China and Russia, the navigation of the Irtysh River is of great significance, and it is particularly necessary to monitor the changes of its river ice phenology. Based on the second band data of MOD09GQ from 2001 to 2018, this paper analyzes the annual river ice phenology information of the Irtysh River from Burqin to Lake Zaysan, including the beginning time of river freezing, the end time of river ice breaking, the maximum coverage time of ice/snow, the duration of river ice period, the freezing rate and the breaking rate. The results show that: (1) the reflectivity of MOD09GQ gradually decreases with the opening of the river ice. Compared with the observed duration of the river ice period at Nanwan station, the obtained duration of the river ice period coincides with the observed duration of the river ice period, and has an extended trend. This shows that MOD09GQ can effectively monitor river ice phenology information. (2) The beginning of river closure and the end of river closure both showed an early trend. The beginning of river closure was 45 days earlier than the end of river closure, and the end of river closure was 31 days earlier than the end of river closure. (3) The closure rate tends to slow down and the opening rate tends to accelerate gradually, which means that if the river reaches are navigable in the future, the annual navigation period will be extended. Bring greater economic benefits.

  • Xin LIU, Zhiying NIU, Yangzi LI, Maoyong HE, Huayu HUANG, Ninglian WANG
    Journal of Glaciology and Geocryology. 2021, 43(4): 1009-1017. https://doi.org/10.7522/j.issn.1000-0240.2021.0061
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    Snow is an important environmental medium and can be used to reflect regional characteristics and to trace sources of air pollution. To understand the spatial distribution and possible sources of arsenic (As) and mercury (Hg) in snow pack, snow pack samples were collected in 58 sample sites from the northern Xinjiang, and dissolved As and Hg concentrations were analyzed using an atomic fluorescence spectroscopy. The spatial distribution pattern was investigated by inverse distance weighted interpolation algorithm, and the possible sources of snow pack As and Hg were tracked by using backward trajectory model. The results indicate that the concentrations of As and Hg were within a range of 0.21 to 2.69 μg?L-1 and 5.32 to 64.09 ng?L-1, respectively. The average concentrations of the dissolved As and Hg in the snow samples were (0.70±0.46) μg?L-1 and (15.94±10.49) ng?L-1, respectively. The average concentrations of the dissolved As and Hg are lower than the standard limit of Chinese surface water quality I, indicating that snow pack As and Hg were less polluted. The inverse distance weight analysis shows that snow pack As and Hg had differences patterns in spatial distribution, and the snow pack As and Hg were mainly influenced by the industrial coal combustion and winter heating. Moreover, the higher concentrations of snow pack As and Hg were observed in the Junggar Basin and northern Tianshan slope, due to the domination of heavy industries in the area. The backward trajectory model analysis shows that the regional/local anthropogenic activities and desert sand transport are likely the sources of As and Hg in the snow pack. However, these pollutants in surface snow were less affected by the long-range transport of air pollution. Our study can provide important scientific insights for assessing the quality of remote ecosystems and implementing air pollution control in northern Xinjiang.

  • Hongliang LI, Puyu WANG, Zhongqin LI, Panpan WANG, Chunhai XU, Shuangshuang LIU, Shuang JIN, Zhengyong ZHANG, Liping XU
    Journal of Glaciology and Geocryology. 2021, 43(4): 1018-1026. https://doi.org/10.7522/j.issn.1000-0240.2021.0068
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    This study reports recent changes of the Urumqi Glacier No.1 during 2012—2018 based on RTK-GPS, terrestrial laser scanning (TLS) and unmanned aerial vehicle (UAV) data. Our analysis suggests that the Urumqi Glacier No.1 had experienced accelerated shrinkage for the investigated periods. The result shows that the total area decreased by 0.07 km2, with a decrease rate of -0.01 km2 a-1 from 2012 to 2018, the terminus retreat rate was 6.28 m·a-1 and its retreat rate from 2015 to 2018 was higher than from 2012 to 2015. Urumqi Glacier No.1 experienced a mean mass loss of (-1.13±0.18) m w.e.·a-1 with lowering surface elevation from 2012 to 2018 and mass loss mainly occurred in the ablation area. It is consistent by comparison between glaciological and geodetic mass balances of the Urumqi Glacier No.1 for 2012 to 2018. The mass loss during 2012—2018 (-0.64 m w.e.·a-1) was greater than that during the period 1980—2012 (-0.47 m w.e.·a-1) indicating that the Urumqi Glacier No.1 continued to shrink recently.

  • Xiaoyu ZHOU, Chunyu ZHAO, Na LI, Mingyan LIU, Yan CUI, Xue AO
    Journal of Glaciology and Geocryology. 2021, 43(4): 1027-1039. https://doi.org/10.7522/j.issn.1000-0240.2021.0069
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    Based on the daily data of frozen soil depth, snow depth, average temperature, average surface temperature and precipitation of 121 meteorological stations in Northeast China, the variation characteristics of frozen soil and the influence on frozen soil by meteorological elements in winter half year of 1964 to 2017 were analyzed. The results show that: the correlation coefficients between snow depth, average temperature, and surface average temperature with frozen soil depth are relatively high, but the correlation with precipitation is small. In the 1960s, the average temperature, average surface temperature and negative accumulated temperature are the lowest, and the maximum frozen soil depth is the deepest; while the climate warming, the maximum frozen soil depth decreased significantly at the rate of 6.15 cm?(10a)-1. In winter-half year, the average maximum frozen soil depth is 123 cm, showing a significant latitudinal distribution, increasing from Liaodong Peninsula to the north of Greater Khingan Mountains; with the increase of latitude and altitude, the average temperature and surface temperature decrease, the negative accumulated temperature increase, and surface-air temperature difference increases from north to south. The maximum depth of frozen soil decreases in more than 90% of the stations, and the decreasing rate is mainly 0.1~10 cm?(10a)-1. The duration of frozen soil increases with the increase of latitude; the monthly maximum depth of frozen soil and snow appear in March and January respectively, and the increase of maximum frozen soil depth lags behind that of snow. Due to the heat preservation effect of snow on surface temperature, the frozen soil depth increases obviously, when the snow depth is shallow, while with the increase of snow depth, the frozen soil depth changes little, snow has played role in insulation on frozen soil. For stations in high latitudes, limit value of snow for heat preservation is about 30 cm; for coastal stations, the limit value of snow for heat preservation is about 5 cm; in the same terrain, the value of snow for heat preservation in shallow frozen soil area also varies with the characteristics of altitude and climate. The response of the maximum frozen soil depth to the rising of the average surface temperature is more significant, the maximum frozen soil depth will decrease by 8.4 cm and 10.6 cm when the average surface temperature and average temperature increases by 1 ℃, and the maximum frozen soil depth will decrease by 4.9 cm when the negative accumulated temperature decreases by 100 ℃·d.

  • Ting HAN, Xiangjie LEI, Yali LI, Yiyong WANG
    Journal of Glaciology and Geocryology. 2021, 43(4): 1040-1048. https://doi.org/10.7522/j.issn.1000-0240.2021.0129
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    Using a total of 37 a high mountain snow observation data from 32 national meteorological stations in the Qinling Mountains in Shaanxi Province from 1980 through 2016, statistical analysis has been done of the regional alpine snow cover processes with 5 or more consecutive days with snow cover more than or equal to 3 days. The regional stable alpine snow cover processes of long-term alpine snow cover process with 5 or more weather stations with continuous snow cover days greater than or equal to 20 days, 5 or more weather stations with continuous snow cover days greater than or equal to 60 days, have been studied also. The results show that in the Qinling Mountains from 1980 through 2016 there were 114 regional alpine snow cover events, including 29 regional long-term alpine snow cover events and 6 regional stable alpine snow cover events. Regional alpine snow cover events occurred from November to April (the cold season), among them 60% occurring in winter (December to February). There were 6 regional stable snow cover events with an average of 73.7 days per snow cover event. The longest regional stable snow cover event, totally lasting 81 days, occurred from November 7, 2003 to April 18, 2004. The number of regional alpine snow events was the highest in the 1980—1989 (44 times), followed by 1990—1999 and 2000—2009 (29 times each), and the least one in 2010—2016 (12 times). The average temperature and precipitation in winter had significantly correlated with the atmospheric circulation index, and had significantly negatively correlated with the Tibetan Plateau Index, the Indo-Burma Basin Intensity Index, the Antarctic Oscillation Index and the Western Pacific Subtropical High West Point Index. Beside, they had clearly positively correlated with the Pacific Trade Wind Index and the Asian Polar Vortex Area Index. In the context of climate warming, the regional snow cover events in the Qinling Mountains had showed a significant reduction trend in 1980—2016, with a reduction rate of -0.8 times/10a. The average number of long-term incidents in various epochs was once a year in the 1980s, 0.9 times a year in the 1990s and only 0.4 times per year in the 1910s. After 2004, there was no regional stable mountain snow cover event in the Qinling Mountains. In 1980—2016, there were 161 snow events in Taibai Station, including 58 long-term snow cover events and 37 snow-stabilizing events. At the 37 a, the regional alpine snow cover events at Taibai Station had showed a decreasing trend with a reduction rate of -0.47 times per 10 years.

  • Qiuyang TAN, Lei CHENG, Zongxue XU, Yanjun ZHAO, Jiangtao LIU, Xiaowan LIU
    Journal of Glaciology and Geocryology. 2021, 43(4): 1049-1059. https://doi.org/10.7522/j.issn.1000-0240.2021.0070
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    Snow cover is an important part of the hydrological process. Based on long-term snow cover depth data set of China, as well as the regional surface meteorological element data from the China Meteorological Data Set (1979—2017), combined with DEM digital elevation model, the spatiotemporal distribution of snow cover depth in the Yarlung Zangbo River basin from 1979 to 2017, as well as the correlation between snow cover depth and meteorological factors (temperature, precipitation), and the correlation between snow cover depth and terrain factors (elevation, slope and aspect) are analyzed by using Mann-Kendall trend test, Sen’s slope estimator and Pearson correlation analysis method. The results show: (1) from 1979 to 2017, the annual average snow cover depth in the Yarlung Zangbo River basin was 1.95 cm, with a decreasing rate of 0.02 cm·a-1; (2) the spatial difference of snow cover depth was obvious, showing a characteristic of "two peaks and two valleys"; the large value area located in the western edge and the eastern mountainous area of the basin, and the small value appeared in the middle valley and the outlet valley; (3) meteorological factor played a decisive role to the variation of snow cover depth; the correlation coefficient between annual average temperature and snow cover depth was -0.63, quite significantly; (4) the snow cover depth increased with elevation, but the maximum snow cover depth did not appeared at the highest elevation; (5) with slope changing, the snow cover depth presented a three-step distribution, i.e., “decrease-increase-decrease”, and the snow cover depth on the east slopes and the south slopes were greater than that on the west slopes and the north slopes.

  • Junze DUAN, Weiyi MAO, Yijing HUANG, Jing CHEN, Tuoliewubieke DILINUER, Junqiang YAO, Yongping SHEN
    Journal of Glaciology and Geocryology. 2021, 43(4): 1060-1072. https://doi.org/10.7522/j.issn.1000-0240.2021.0071
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    Using the daily minimum temperature of Nursultan and Urumqi from 1951 to 2016, the characteristics of cold waves were compared and the relationship between Arctic Oscillation (AO), North Atlantic Oscillation (NAO) and the cold wave in two cities were analyzed. From this July to next June was regarded as a statistic year in this paper.The results show that: (1) The average annual cold wave frequency of Nursultan (15.7 times·a-1) is 3.88 times that of Urumqi (4.1 times·a-1), strong cold wave and super cold wave is 5.91 and 7.55 times, respectively. The distribution of the super cold wave in Nursultan is unimodal, the most in January, and the Urumqi is bimodal, with peaks appearing in November and April. The cold wave process in Nursultan is generally shorter than Urumqi. (2) There was a significant correlation between Nursultan and Urumqi in recent 65 years. The annual frequency linear decline rates of the cold wave in Nursultan and Urumqi are -0.111 times·(10a)-1 and -0.445 times·(10a)-1, respectively. The linear trend of cold wave, strong and super cold wave frequencies were decline, except winter in Nursultan and spring in Urumqi. The cold wave in Nursultan is most frequent in the last 5 years, and it has a significant period with 31 years and 20 years. The frequency of the annual cold wave in Urumqi has a significant period of around 39 years and 8 years. (3) The NAO is more closely related to the cold wave of Nursultan and Urumqi than the AO. The frequency of the cold wave in Nursultan is more affected by NAO and AO.

  • Yitian LIU, Jimin YAO, Lin ZHAO, Yao XIAO, Yongping QIAO, Jianzong SHI
    Journal of Glaciology and Geocryology. 2021, 43(4): 1073-1082. https://doi.org/10.7522/j.issn.1000-0240.2021.0072
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    There are few studies on the influence of the freeze-thaw cycle on surface energy in the permafrost region of the Qinghai-Tibet Plateau. Based on the measured data of Tanggula permafrost, to divides each stage of the freeze-thaw cycle of the active layer according to the 10 cm soil temperature. Combine with surface energy closure and surface energy fluxes to discuss the influence between freeze-thaw cycle of active layer and water-heat exchange. The results show that: each stage of the freeze-thaw cycle of the active layer is affected by climate change. The starting time of the thawing process is advancing and the starting time of the freezing process is delayed. As a result, the duration of soil complete thawing increases and gradually approaches that of complete freezing; in different freeze-thaw states of shallow soil, the energy closure rate different is large, and the energy closure in the stage of complete thawing is generally better than that in the stage of complete freezing; the net radiation value in the stage of complete melting is higher than that in the stage of complete freezing, sensible heat flux dominates in the stage of complete freezing, latent heat flux dominates in the stage of complete melting, and surface soil heat flux is positive in the stage of complete melting and negative in the stage of complete freezing.

  • Doudou JIN, Ze ZHANG, Wenjie FENG, Jinguo WANG, Pan YUE, Shuguang YANG
    Journal of Glaciology and Geocryology. 2021, 43(4): 1083-1091. https://doi.org/10.7522/j.issn.1000-0240.2021.0030
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    Studies have found that unfrozen water in frozen soil will migrate under the action of electrification. This continuous migration is a complex physical and chemical process and is eventually accompanied by a process of frost heave. Laboratory tests of frozen Lanzhou loess were conducted to investigate the electro-osmosis effects of deformation, distribution of water content, current and energy consumed of each test, the following conclusions were drawn. With the increase of the electric potential gradient, the difference between the deformation of the anode and the cathode of the soil gradually increases, and the cathodes both expand and the anodes settle; with the increase of the electric potential gradient, the amount of water migration from the anode to the cathode increasing, the amplitude of current reduction increases, and the change characteristics of the two are similar to the change characteristics of the water content difference; under a potential gradient of 5 V?cm-1, the total energy consumption of electric energy is the largest, and the energy consumption per unit of water content is the smallest.

  • Mingli ZHANG, Bin WANG, Dekai WANG, Weilin YE, Zongyun GUO, Qiang GAO, Guodong YUE
    Journal of Glaciology and Geocryology. 2021, 43(4): 1092-1101. https://doi.org/10.7522/j.issn.1000-0240.2021.0073
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    Changes of surface radiation on the Qinghai-Tibet Plateau affect the energy balance of the permafrost region, the boundary conditions of the temperature field in thermal calculation and the thermal stability of permafrost. Rainfall is the key factor affecting the surface radiation. Based on the surface radiation and shallow surface water-heat data of the Qinghai-Tibet Plateau Beiluhe area, the effects of rainfall on surface radiation were analyzed. The results show that under the influence of precipitation the radiation component has obvious diurnal and interannual variation characteristics. The short-wave radiation is seriously weakened, the long-wave radiation on the ground is slightly weakened, while the long-wave radiation of the sun is enhanced. After the action of light rain, the daily volume of solar short wave, ground short wave and ground long wave decreased by 24.6%, 37.9% and 4.2% respectively, and the solar long wave increased by 4.3%.After the action of rainfall, the daily volume of solar short wave, ground short wave and ground long wave decreased by 32.2%, 43.4% and 1.7% respectively, and the solar long wave increased by 11.6%.After the effect of heavy rain, the daily volume of solar short wave, ground short wave and ground long wave decreased by 56.3%, 65.5% and 4.4% respectively. The solar long wave increased by 10.7%. Rainfall decreases the surface albedo and increases the net surface radiation. The surface albedo presents an asymmetric U-shape and the effect of long-term rainfall on net radiation is not obvious. The effect of rainfall on radiation characteristics is positively correlated with rainfall intensity and the response of surface radiation to rainfall has a hysteresis effect. In the climate warming and wetting scenario, the effect of rainfall on the surface energy balance and water thermal boundary of permafrost regions should be considered in the thermal calculation of permafrost and the thermal simulation of frozen soil.

  • Siqi LI, Ping YANG, Ting ZHANG, Jun’an BAO
    Journal of Glaciology and Geocryology. 2021, 43(4): 1102-1110. https://doi.org/10.7522/j.issn.1000-0240.2018.1194
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    In order to study the frost heave and thaw settlement properties, experimental researches were carried out with silty clay in Nanjing region. Test control factors include the mixing ratio of cement, moisture content, age, cold junction temperature and load. Each control factor selects representative conditions within the interval containing the benchmark value to conduct a single variable test. The test was carried out with frost heave and thaw settlement instrument. The lower part of the instrument was equipped with a refrigeration block, and the upper part was equipped with a water supplement, to simulate water migration process when real soil is frozen. Frost heave of cement-improved silty clay declines exponentially with mixing ratio of cement and age increasing, enhances linearly with moisture content, cold junction temperature rising and load reducing. The mixing ratio of cement also influences thaw settlement of cement-improved silty clay, which is in line with the law in frost heave. Thaw-settlement coefficient is higher than frost heaving ratio in same situation. The time of completing thaw settlement declines with thawing temperature, while thawing temperature has no impact on final thaw-settlement coefficient. The reasonable mixing ratio of silty clay in Nanjing is 10%. Frost heaving ratio is 1.56% and thaw-settlement coefficient is 2.15% in reasonable mixing ratio. In conclusion, mixing cement into soil beforehand can control frost heave and thaw settlement effectively in artificial freezing construction and enhance productivity.

  • Zhengmin SONG, Yanhu MU, Wei MA, Qihao YU, Xiaolin LI
    Journal of Glaciology and Geocryology. 2021, 43(4): 1111-1120. https://doi.org/10.7522/j.issn.1000-0240.2021.0074
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    In high altitude permafrost regions, roadway embankment construction will exert significant impacts on underlying permafrost thermal regime. In order to protect the long-term stability of permafrost subgrad, ventilation duct embankment is an effective cooling measure used in roadway construction. For ventilation duct embankment, wind speed in ventilation duct is an important factor determining the intensity of convection heat transfer between environment and embankment filling. In this paper, characteristics and influence factors of wind speed in ventilation duct of ventilation duct embankment are studied by field measurement and numerical simulation. The results shows that wind speed in ventilation duct increase exponentially with increasing diameter of the duct. But when the diameter of the duct is greater than 0.6 m, the wind speed does not increase further. The influence of extended length of the ventilation duct on the wind speed is slight, but with increasing environmental wind speed the influence becomes considerable. The wind speed in the ventilation duct add with increase in ventilation duct buried depth. When the buried depth is greater than 2 m, the wind speed does not change considerable. When roadway is constructed with two separated embankments, the wind speed in ventilation duct of the leeward embankment will be influenced by the windward embankment. Taking the discrepancy of wind speeds in the ventilation ducts of the two embankments not exceeding 0.4 m·s-1 as a standard, the minimum spacing between the two separated embankments is about 50 m with their thickness being 3 m.

  • Ze’an XIAO, Linze ZHU, Zhenrong HOU, Xiaoqiang DONG
    Journal of Glaciology and Geocryology. 2021, 43(4): 1121-1129. https://doi.org/10.7522/j.issn.1000-0240.2021.0064
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    Saline soil is widely distributed in cold and arid regions of Northwest China. Detrimental frost heave and salt expansion occur in these areas due to harsh natural conditions, and then cause great damage to the stability of the engineering structures. Salt expansion and frost heave are caused by salt crystallization and ice formation, respectively; then the phase transition temperatures become very important to judge the water freezing-thawing and salt crystallization-dissolution in saline soil. Multiple ions exist in the pore solution of natural saline soil, but the phase transition mechanism of the multi-component pore solution in saline soil is studied less. In order to explore the water and salt phase transition mechanism of multi-component pore solution in the freezing process, remolded loess on Datong basin (in Shanxi Province) was taken as research object, and two kinds of salts (sodium chloride and sodium sulfate) were chosen; by changing the mass ratio of sodium chloride and sodium sulfate under different total salt contents, the phase transition temperatures of ternary pore solution during cooling were investigated. In the cooling tests, the temperature was controlled by cold bath (TMS8035-R40, precision: ±0.01 ℃). Considering the salt solubility, the cold bath was first set to 30 ℃ for a specific period of time to maintain the consistent temperature of each soil samples, and then the cold bath was adjusted to -30 ℃ for cooling the soil samples. The temperatures of soil samples were measured by high-precision temperature sensor (precision: ±0.05 ℃) at intervals of 10 s, and CR300 was used to collect the measured data for later analysis. If there is no phase change occurs in saline soil during the cooling process, the cooling curve is continuous. And temperature mutation appears on the cooling curve, when phase change occurs. The temperature mutation indicates the phase transition of pore solution (ice formation or salt crystallization), and the latent heat of phase change compensates the heat lost from the system to the environment. By drawing the cooling curves of soil samples, the temperature mutation points are obtained, then the phase transition mechanism are determined based on the phase diagram of aqueous solution. The experimental results showed that the crystallization temperature varies with the mass ratio of sodium chloride and sodium sulfate under the same total salt content. With adding an appropriate amount of sodium chloride, sodium sulfate is easier to crystallize under the common-ion effect of sodium ion. However, the eutectic temperature of ice and mirabilite in soil decreases, reducing the proportion of solid phase in pore solution, thus restrain the salt expansion and frost heave of sulfatesaline soil. When only sodium sulfate exists in saline soil, the eutectic temperature of ice and mirabilite first increases, and then decreases slowly with sodium sulfate increasing. The leading cause of this tendency is the accumulation of ice and hydrated salt before the second phase transition stage. The three-phase eutectic temperature of saline soil increases with the increase of sodium chloride content. This is because the solid phase content in pore solution decreases with the addition of sodium chloride before three-phase eutectic point, which makes a less impact of pore structure. In addition, for saline soil containing sodium chloride and sodium sulfate, water and salt may precipitate in single solid phase, double solid phase and three solid phase state. The diversity of phase transition temperature of different salt content brings great uncertainty for modeling the water and salt migration and deformation of saline soil during cooling. The result of this study will further enrich the related theory of saline soil in cold area, and it is helpful for understanding the phase transition mechanism and properties of saline soil in freezing process.

  • Tianhao HE, Hongkai GAO, Xiangying LI, Tianding HAN, Zhihua HE, Zhicai ZHANG, Zheng DUAN, Min LIU, Yongjian DING
    Journal of Glaciology and Geocryology. 2021, 43(4): 1130-1143. https://doi.org/10.7522/j.issn.1000-0240.2021.0053
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    The hydrological model of glacier basin is an important method to study glacier water resources, but its uncertainty affects its wide application and the ability to support decision-making. Water stable isotope tracing provides important “fingerprint” information for understanding the runoff process of glacier basins, but there is still a lack of effective models to couple this information with glacier hydrological models, and the effect of stable isotope information on the uncertainty of hydrological models of glacier basins at different time and space scales also needs to be tested. In this study, the water stable isotope information (δ18O) is coupled with the glacier-hydrological model FLEXG to realize the coupled modeling of the water stable isotope and runoff process (FLEXG-iso) of the glacier basin. We take the catchment of Glacier No. 1 in headwater of Urumqi River as the research area. The data used are the temperature, precipitation and runoff data of the Glacier No. 1 hydrological station from 2013 to 2016, the stable isotope data (δ18O) of rainfall and runoff measured during the same period, and the Glacier No. 1 glacial material balancing data, terrain data and the Second Chinese Glacier Inventory. To compare the effects of stable water isotope information on the quantitative simulation and uncertainty range of runoff process, four schemes with different calibration data design by using the glacier-hydrological model (FLEXG-iso) coupled with water stable isotope information (δ18O). Finally, based on the simulation results, the runoff composition of the Glacier No.1 in headwater of Urumqi River section is analyzed. The results show that: under the four schemes, the model not only has a good simulation of the runoff process during 2013—2016, but also can reproduce important processes such as stable water isotope and glacial mass balance. The use of stable water isotope data for the model calibration test improves the reliability of the simulation results during calibration period and evaluation period, resulting in a lower uncertainty range. During calibration period and evaluation period, Scheme 4 has the smallest uncertainty range and good simulation results (the mean KGE of runoff depth is greater than 0.8, the mean square error of runoff δ18O is less than 0.61‰, and the mean volume deviation efficiency of the glacier mass balance is less than 0.37). Comparing the four schemes, most of the parameters of Scheme 4 produce the smallest uncertainty range, which shows that the water isotope data has the ability to further restrict the parameters. The use of water stable isotopes as auxiliary data improves the identification of model parameters, especially the parameters related to snow and glacier runoff processes (TtFddCwh and Kf,g), and reduces the mutual compromise effect of various water sources in the simulation process and the uncertainty range. Calculated from Scheme 4, from 2013 to 2016, about 32%~34% of the runoff from Glacier No.1 in headwater of Urumqi River came from snowmelt, 48%~51% from melting ice, 0%~7% from groundwater, and 12%~15% from rainfall runoff. In the ablation season, melting ice is the largest runoff component, while snowmelt is the second largest runoff component, followed by rainfall runoff, and finally groundwater. In the non- ablation season, snowmelt and groundwater dominate, and ice melting and rainfall runoff contribute little. Stable water isotopes have obvious constraints on the intermediate processes related to snow and glaciers, and the original model’s simulation of the contribution to ice melting is about 7% higher. The establishment of the FLEXG-iso model establishes a bridge for communication between experiment and model scientists, and helps to promote the development of hydrological theories and methods in cold regions, as well as decision-making related to water resources and ecological environment protection in cold regions.

  • Kewei HUANG, Genxu WANG, Chunlin SONG, Qihao YU
    Journal of Glaciology and Geocryology. 2021, 43(4): 1144-1156. https://doi.org/10.7522/j.issn.1000-0240.2021.0056
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    The Qinghai-Tibet Plateau, known as the Third Pole, with 42.4% permafrost coverage, is sensitive to climate change. Runoff generation of small-scale watershed with high permafrost coverage is significantly controlled by temperature factor, which makes ordinary hydrological model unsuitable for this area, while lack of measured data such as soil temperature and moisture makes common permafrost hydrological model difficult to be applied. Moreover, increase in air temperature will result in permafrost degradation, which fundamentally changes the hydrogeological conditions in permafrost regions and finally changes the runoff process in permafrost watershed. Thus, the air temperature is a key factor in permafrost runoff modeling. LSTM (long short-term memory) is a special recurrent neural network with a more detailed internal processing unit, which contains cell state and gate structures, helping it effectively use long-distance time series information in hydrology. In this study, we developed a permafrost hydrological model at small-scale watershed based on LSTM neural networks with the consideration of runoff generation mechanism in permafrost. And it was applied in Fenghuoshan watershed, a tributary of the source region of the Yangtze River with 100% permafrost coverage, located at the central of Qinghai-Tibet Plateau. In the LSTM permafrost hydrological model, the precipitation and air temperature are employed as model inputs, while the runoff is regarded as the output. The daily precipitation, air temperature, and runoff observation data from year 2017 to 2018 were employed to train the model, and the dataset of year 2019 was used for model validation. Benefiting from the special cell state and gate structures of LSTM, the model is capable of learning and reflecting freeze-thaw processes and soil moisture seasonal variation in the active layer, with cell state evolution of some LSTM neurons consistent with these processes. It gives the model a certain permafrost hydrological significance and the high performance of permafrost runoff simulation. The values of R2, NSE and RMSE were 0.93, 0.93, 0.63 m3·s-1 during training period, 0.81, 0.77, 0.69 m3·s-1 during validation period, respectively. Besides, the model performed well in all periods within the year, including spring flood period, summer recession period, summer flood period, autumn recession period and winter freezing period. The model was also applied in the Tuotuohe watershed, which is close to Fenghuoshan watershed. The values of R2, NSE were 0.73, 0.73 during training period, 0.66, 0.64 during validation period, respectively. The model result was comparable to the results of CRHM model and WEB-DHM-SF model, which demonstrates it was reasonable and reliable. And the model was employed to predict runoff changes of Fenghuoshan watershed under 10 different climate change scenarios, those were 10% or 20% increase in precipitation with 0 ℃, 1.0 ℃, 2.0 ℃ increase in air temperature and 0.5 ℃, 1.0 ℃, 1.5 ℃, 2.0 ℃ increase in air temperature with precipitation unchanged. It shows that every 10% increase in the precipitation will result in approximately 12% increase in the annual runoff, while every 0.5 ℃ increase in the air temperature will result in approximately 1% increase. The thaw of underground ice induced by increase in air temperature contributes little to the runoff increase. However, it significantly changes the runoff process through altering the freeze-thaw processes in the active layer, which has a different influence on the runoff during different periods. Increase in the air temperature will result in significant increase in the runoff during spring thaw and autumn freeze period, while the runoff decreases in August due to the increased evaporation and deepened active layer caused by the increase in the air temperature. Meanwhile, increase in the air temperature prolongs the thaw period and shortens the freeze period, which will change the runoff compositions. This illustrates the temperature-induced variable source area runoff generation process, namely the runoff generation in permafrost region not solely determined by soil moisture but controlled by temperature conditions. The results show that the trained model can be employed to simulate and predict runoff of small permafrost watershed with only precipitation and air temperature as inputs, which are easier available in permafrost areas. It provides a simple and effective method, with a certain physical meaning, for permafrost watershed lacking observation data such as soil temperature and moisture.

  • Huan MOU, Li ZHAO, Xu WANG, Dawei AN
    Journal of Glaciology and Geocryology. 2021, 43(4): 1157-1165. https://doi.org/10.7522/j.issn.1000-0240.2021.0037
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    By using the data from automatic weather stations in Xinjiang, the NCEP/NCAR reanalysis data, GDAS data and the airflow trajectory model based on the Lagrangian Method (HYSPLITv4.9), the water vapor sources and moisture transport paths of a severe torrential in the western of southern Xinjiang from May 16 to 22, 2018 were analyzed. The results of HYSPLIT backward trajectories simulation showed that the severe torrential water vapor originates from the Barents Sea, the Kara Sea, the Norway Sea and the Mediterranean Sea, and the water vapor in the two regions first transported to the downstream along the northwest stream and the western stream, respectively. After converging in the Kazakh Hills, the water vapor trajectories entered the northern Xinjiang, then bypassed the eastern side of the Tianshan Mountains to reach the Lop Nur, and then reached the upper part of the severe torrential area with the lower level easterly jet. Although the water vapor trajectories from the Barents Sea, the Kara Sea and the Norway Sea were slightly more than those in the Mediterranean Sea, the contribution rates of water vapor were 62% and 38%, respectively, in the two regions. Therefore, the water vapor of Barents Sea, Kara Sea and Norway Sea played an obvious role in strengthening the rainstorm. In addition, there was no low-level eastward water vapor from the Bay of Bengal in the simulation result of backward trajectories, which indicated that the water vapor in this region was not a necessary condition for the formation of severe torrential water vapor in the western part of southern Xinjiang. It was found that the sea surface temperature anomalies in the Barents Sea, the Kara Sea, the Norway Sea of the Arctic were high, which basically coincide with the moisture source regions of the severe torrential. The results indicated that the anomalously high sea surface temperature in the Arctic was conducive to enhanced evaporation from the water vapor source and the formation of an updraft background field, and that the temperature anomalies in the Arctic waters were a good indicator of regional climate change.

  • Yaman ZHOU, Jing LIU, Yong ZHAO, Chao MA, Na LI
    Journal of Glaciology and Geocryology. 2021, 43(4): 1166-1178. https://doi.org/10.7522/j.issn.1000-0240.2021.0075
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    Based on the daily precipitation data of 47 stations in northern Xinjiang, NOAA SST data and NCEP/NCAR reanalysis data from 1961 to 2017, the precipitation threshold of single station in northern Xinjiang in summer was determined by using 90% position, and the extreme precipitation was obtained. The relationship between tropical sea surface temperature in spring and extreme summer precipitation in northern Xinjiang was discussed. The results show that: the extreme summer precipitation in northern Xinjiang was positively correlated with the sea surface temperature in the Indian Ocean (20° S~15° N, 50°~110° E) and the eastern equatorial Pacific (15° S~15° N, 90°~180° W) in spring. When the sea surface temperature in the two key regions were abnormally warmer in spring, the extreme summer precipitation in northern Xinjiang was increased. Only when the sea surface temperature in the key region of the Indian Ocean was abnormally warmer in spring, the extreme summer precipitation was increased in the northwest of northern Xinjiang. When the sea surface temperature in the two key regions of the Indian Ocean and the eastern equatorial Pacific increased abnormally in spring, the axis of westerly jet was obviously southward at 200 hPa, the low-value systems were active in western Siberia and Central Asia at 500 hPa, and the increase of moisture transported by the southern route was conducive to the occurrence of extreme summer precipitation in northern Xinjiang. Only when the sea surface temperature in the key region of the Indian Ocean was abnormally warmer in spring, the intensity of westerly jet increased at 200 hPa, the low value systems were active in western Siberia at 500 hPa, the extreme summer precipitation in the northwest region of northern Xinjiang was increased which cooperated with the water vapor transportation in the eastward path.

  • Xiuna WANG, Yongjian DING, Jian WANG, Chuancheng ZHAO
    Journal of Glaciology and Geocryology. 2021, 43(4): 1179-1189. https://doi.org/10.7522/j.issn.1000-0240.2018.1151
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    Based on the daily precipitation data of 18 meteorological stations in the Hexi region from 1960 to 2017, linear trend analysis, sliding average and Thiessen polygon method were employed to analyze the spatial and temporal precipitation variability and the variation trend of rainy days and precipitation intensity at different precipitation magnitudes. Results show that the average annual rainfall in the Hexi region is 99.0 mm?a-1 and represents a decreasing trend from southeast to northwest. The average annual rainfall showed an increasing trend with the interannual variation rate of 8.72 mm?(10a)-1. The annual distribution of precipitation presents a unimodal character and shows a distinct seasonal distribution, with more than 89.2% of annual rainfall occurred in summer and autumn. The average number of annual rainy days in the Hexi region is 36.7 days, showing a significant increasing trend, with the interannual variation rate of 3.18 d?(10a)-1. The rainy days are mainly concentrated in summer and represent a decreasing trend from southeast to northwest. The average precipitation intensity in the Hexi region is 2.70 mm?d-1, showing a decreasing trend, with the interannual variation rate of -0.04 mm?d-1?(10a)-1. The precipitation days of sporadic light rain, light rain and light to moderate rain showed an increasing trend, with growth rates of 1.70 d?(10a)-1, 1.13 d?(10a)-1 and 0.16 d?(10a)-1, respectively. The average precipitation intensity of sporadic light rain and light rain showed a decreasing trend, with the rates of -0.02 mm?d-1?(100a)-1 and -0.21 mm?d-1?(100a)-1, but the average precipitation intensity of light to moderate rain showed an increasing trend, with the rate of 0.07 mm?d-1?(100a)-1. There are fewer precipitation events in moderate rains and above, and most stations are less than one time in a year, thus the long-term trend is not obvious.

  • Shaoning LI, Xiaopeng JIA
    Journal of Glaciology and Geocryology. 2021, 43(4): 1190-1199. https://doi.org/10.7522/j.issn.1000-0240.2021.0076
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    Water resources are scarce in the arid region in Northwest China, and the ecological environment is fragile. In the context of global climate change and human activity interference, the use of isotope methods to conduct fine-scale surface water-groundwater interaction studies is a basic requirement for exploring local water cycle changes and water resources management. Research of water cycle and runoff variation has always been a difficult issue of assessment of water resources in arid basins. In May and August, 2019, samples of river water and groundwater had taken, then 222Rn concentration of these samples were measured and river runoff were also gauged. Then spatial and temporal characteristics of 222Rn concentrations in river water and groundwater had analyzed, together with interactions between them. The results show that (1) 222Rn concentration of river water in mountains are high, with a mean value of 948.72 Bq·m-3, indicating that groundwater coming out of bedrock fissure water is an important source of river water in the mountains, especially near a tectonic faults; (2) 222Rn concentration of river water in the alluvial floodplain with less groundwater recharge are low, 76.71 Bq·m-3 inaverage; (3) 222Rn concentration rises to average 676 Bq·m-3 in the transitional zone of alluvial floodplain and low-lying plain, where groundwater recharges to the river as spring. Toward downstream low plain, 222Rn concentration of river water go down again; (4) temporally, compared to May, 222Rn concentration of river water is relatively low in August, showing a decline of groundwater recharge; (5) 222Rn concentration of groundwater is 2-3 orders of magnitude higher than river water and demonstrate a spatial variation of high in the middle whereas low in the east and west; (6) in S1~S2, two concurrent processes of groundwater discharging to river and river water leaking to groundwater dominate the surface-groundwater interaction. A mass balance method was used to calculate the exchange flux which indicates accumulated river leakage flux in May and August is 3.87 m3?s-1 and 0.9 m3?s-1, separately, while 0.51 m3?s-1 and 0.47 m3?s-1 for groundwater discharge flux. River leakage is more powerful than river discharge and the flow flux between surface and groundwater varies noticeably in different sections and different time.

  • Junxin JIANG, Ming CAI, Yongjun XU, Gonghuan FANG, Zhi LI, Yongjin CHEN
    Journal of Glaciology and Geocryology. 2021, 43(4): 1200-1209. https://doi.org/10.7522/j.issn.1000-0240.2021.0128
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    Global warming has accelerated water cycling and increased flood risk. The Aksu River basin, located on the southern slope of the Tianshan Mountains, is an important tributary of the Tarim River basin. Floods in the Aksu River basin is not only caused by storm, glacier and snow melt water, but also glacial-lake outburst floods (GLOF). Based on the long-term daily streamflow data of the Kumarak River and the Toshgan River, two headwaters of the Aksu River, this study investigated the changing nature of flood events from 1958 to 2011. In addition to the bulk maximum method, this work also applied the Peak Over Threshold (POT) method to extract flood events and 106 and 112 flood events were identified in the Kumarak River and the Toshgan River, concentrated in June, July and August. The flood intensity of the Kumarak River and the Toshgan River both increased based on the two flood-identification methods. The occurring time of flood of the glacier-melt water dominated Kumarak River has pushed forward, while that of the rainfall and snowmelt recharged Toshgan River has become more dispersed as the spring flood being pushed forward while the autumn flood being postponed.

  • Wenkang DOU, Zeping WANG, Jinxin FANG, Tongtong HAN, Tao PU, Peng ZHANG
    Journal of Glaciology and Geocryology. 2021, 43(4): 1210-1217. https://doi.org/10.7522/j.issn.1000-0240.2021.0009
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    Yulong Snow Mountain is the most typical representative area for the development of marine monsoon glaciers in China, and it is also the nearest modern glacier area to the equator in the northern hemisphere. Part of Lijiang’s water source comes from the meltwater of the Yulong Snow Mountain glaciers, and the Yulong Snow Mountain Scenic Area attracts tens of millions of tourists every year to admire the modern glaciers. Tourism activities are closely related to and interact with the water environment. The accurate description of the water environment is the basis for guiding and optimizing regional tourism activities. Taking the world-famous tourist city of Lijiang as an example, based on field sampling and data analysis, a coupling analysis of the tourism activities and water environment of Lijiang in 2018 was carried out. The results show that the coupling degree between tourism activities and water pollution in Lijiang basin is extremely high, and the coupling degree between tourism activities and water eutrophication and water toxicity is low. There is a strong correlation between tourism activities and the water environment, especially the permanganate index in the water environment indicators, there is a strong coupling relationship. In general, tourism activities have a correlation with the water environment, and the quality of the water environment in the peak tourist season is worse than in the off-season.

  • Penglong WANG, Xiaoyu SONG, Bao WANG, Xiaobo WANG, Yibo NIU
    Journal of Glaciology and Geocryology. 2021, 43(4): 1218-1227. https://doi.org/10.7522/j.issn.1000-0240.2021.0077
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    Water rights for towns is the premise of the research on water resources carrying capacity in towns. It lays groundwork for implementation of the strictest water resources management and water right trade system in town, and provides material guarantee for rural revitalization and beautiful rural construction in the new era. The total water consumption control target of Ganzhou determined by the strictest water resource management system is adopted as total distributable water rights. On the basis of giving priority to ensuring basic use for domestic water and ecological water, 2017 selected as the planning level year, five methods, namely the single index of population, area, output value, and mixed index model, and comprehensive index model, are adopted to carry out a comparative study on water rights allocation at the town level. The results show that: (1) experts pay more attention to equity than efficiency in water rights allocation. Regional water resource managers pay more attention to equity in water rights allocation, while researchers tend to be more efficient. (2) The allocation result of water rights in the same township is relatively even under the five models, but the proportions of water rights in the specific towns are different due to different emphasis of the five methods. In each town, the proportion of maximum water rights in different modes is above 10%, while the minimum proportion is less than 0.3%. (3) The comprehensive index allocation model, based on Analytic Hierarchy Process, produces more rational results, and the results are more in line with the current situation of water resources utilization and future economic and social development potential of every town, which lays a foundation for the research of water resources carrying capacity in town level.

  • Nai’ang WANG, Antuk, Dehao SUN, Xiao LIU, Chen’ao LU, Nan MENG, Dan YANG, Yuanyuan WANG, Zhenxin XI
    Journal of Glaciology and Geocryology. 2021, 43(4): 1228-1242. https://doi.org/10.7522/j.issn.1000-0240.2021.0078
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    Geomorphology and sedimentology evidences show that the relics of geological disasters in Shandong Mengshan Mountains are prevalent. They are usually distributed along the channels in the form of debris levees and accumulation terraces. Among them, Eyukou boulder levee is one of the most typical and representative levees. To gain a deeper understanding of the Quaternary environmental change process in Eastern China (east of 105° E) and to improve geo-science education better, it is of critical significance to clarify the formation history and genetic type of the Eyukou boulder levee. During the two field trips to Mengshan Mountains in October 2020 and February 2021, a series of data was collected, several sets of gravel fabric measurement data and four AMS14C dating samples of dead tree trunks which was found in the crevices of boulders were reported here. The results show that: (1) The Eyukou Levee distributed on the cut bank at downstream Eyu Valley discontinuously and asymmetrically. Its depositional features including gravel fabric, roundness, stone-trace structure, cavernous structure of stacked boulders and structure of boulders group along with the brightness of scratches on the surface of boulders can definitely attribute Eyukou Levee to a debris flow genesis occurred several hundred years ago and was transformed by the later mountain floods. (2) According to the AMS 14C dating results and remote sensing data, a catastrophic flood was occurred in Eyukou Levee about 30 years ago, which is consistent with a recorded geological disaster happened in Summer 1991. It further enhances the possibility that the Eyukou Levee was formed by catastrophic debris flows. (3) The historical debris flows may be a rapid geomorphological disaster process which is induced by torrential rain. The materials mainly come from the mass movement process, which occurred in the upper of Eyukou. This result is consistent with the fresh scratches on the surface of boulders and supported by the historical records of modern debris flows. (4) The formation of Eyukou Levee is irrelevant to frost-action, additionally the levee is not a block stream. The reported “block stream” in Mengshan Mountains is unreliable due to the lack of reliable evidence of combined geomorphological features, and chronological or sedimentological evidence. The local climate does not have the conditions for the formation of block stream or permafrost environment in the Early Holocene. (5) The Mengshan region is rich in detrital materials with steep longitudinal profiles. During torrential rains, debris flows have a high possibility to occur. Therefore, surrounding residential areas, roads and hiking trails should strengthen the prevention of geological disaster, especially debris flows.

  • Hongchao LIU, Junjie MA, Ren LI
    Journal of Glaciology and Geocryology. 2021, 43(4): 1243-1252. https://doi.org/10.7522/j.issn.1000-0240.2021.0079
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    Based on the meteorological observation data from 2004 to 2012 at Tangula Station, using the KNN algorithm, combined with machine learning ideas, a meteorological regression model was established to simulate the surface soil water-theamal change trend in Tangula region in 2005, and the measured values were combined with the observed values. The value comparison is made to evaluate the simulation effect of the model. The results show that the KNN model can well simulate the hydrothermal conditions of the soil in the active layer. The results show that the KNN model can well simulate the soil water and heat conditions in the active layer, and the correlation coefficients between the simulated values of the simulated soil temperature and the observed values are above 0.99, and the root mean square error is within 1.25 ℃; The correlation coefficients between the simulated and observed values of soil moisture are above 0.95, and the root mean square error is within 0.02 m3?m-3. In general, the KNN model can simulate the hydrothermal process of Tangula station in the permafrost region of the Qinghai-Tibet Plateau, and its applicability to other parts of the Qinghai-Tibet Plateau needs further research and verification.

  • Shuping YANG, Haidong HAN, Feiteng WANG, Yanqun BI, Xing WANG
    Journal of Glaciology and Geocryology. 2021, 43(4): 1253-1266. https://doi.org/10.7522/j.issn.1000-0240.2021.0080
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    Snow storage is one of the effective measures to solve the problems caused by climate warming, such as shorter operation time of ski resorts, higher snow production cost and lack of snow guarantee for large-scale sports events. However, there is a shortage of research on snow storage technology based on efficient thermal insulation structures and new materials, which cannot meet the increasing demand for skiing events and entertainment. In order to select the optimal technical scheme for snow storage, four snow storage banks with comparable construction costs were set up in Wanlong Ski Resort in Chongli District, Zhangjiakou City, Hebei Province, based on different thermal insulation materials and thermal insulation structures. The results show that: from the outside, inside and inside of the main heat insulation structures to the snow surface, the temperature fluctuation decreases gradually, and the difference of heat insulation performance of different heat insulation structures is gradually. Among the four snow banks, the vacuum interlayer in snow bank had the best thermal insulation effect, followed by the thick layer polyurethane snow bank, the multi-layer hollow snow bank, and the vacuum insulating plate had the worst thermal insulation effect. According to the test results, it is recommended to use vacuum sandwich insulation structures and thick insulation material for snow storage.