25 December 2018, Volume 40 Issue 6
    

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  • LIU Guangyue, XIE Changwei, YANG Shuhua
    Journal of Glaciology and Geocryology. 2018, 40(6): 1067-1078. https://doi.org/10.7522/j.issn.1000-0240.2018.0413
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    The situation of freezing and thawing within the active layer has a vital influence on the climate system, energy balance, hydrological processes and ecological system, and the onset date of freezing and thawing is an important index to describe the spatial and temporal variations of freezing and thawing condition. In order to find out the influence factors and process on onset of freezing and thawing within the active layer, eight typical observation sites in permafrost regions along the Qinghai-Tibet Highway were selected, and their onset date of freezing (OOF) and the onset date of thawing (OOT) at each site are analyzed. The analyses showed that:(1) Within the active layer in permafrost on the Tibetan Plateau, the initial thawing occurs mainly in the middle to late April, and the initial freezing occurs mainly in the middle to late October; the annual variation of OOT is greater than that of OOF, and the freezing of the active layer occurs more regular than thawing. (2) The air temperature when the initial thawing of the active layer occurs is generally 1-4℃ higher than that when the initial freezing occurs; the effect of air temperature at OOT is greater than that at OOF; the variation of OOT is mainly related to the mean air temperature in spring, and barely influenced by the mean air temperature in winter. (3) Vegetation and soil moisture play an important role to OOT and OOF; high soil moisture, as well as nice vegetation, generally delays the onset of freezing and thawing. (4) When the freezing or thawing is about to start, snow cover with great depth or rather long duration obviously inhibits the rising of ground temperature and then delays the OOT and OOF, however, this is an occasional event.
  • LI Lin, LI Hongmei, SHEN Hongyan, LIU Caihong, MA Yucai, ZHAO Yucheng
    Journal of Glaciology and Geocryology. 2018, 40(6): 1079-1089. https://doi.org/10.7522/j.issn.1000-0240.2018.0117
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    By using the monthly temperature, precipitation and greenhouse gases data from 88 meteorological stations in the Qinghai-Tibet Plateau from 1961 to 2012 as well as climate change scenarios data determined by CMIP5, several truth about warm and wet climate in the plateau for the 52 years are analyzed. The correlations among greenhouse gas, plateau heating field, plateau monsoon and the Arctic Oscillation (AO) index with its inter-annual oscillation are revealed. The possible climate change trend in the future 30-50 years is predicted. The results show that the warming trend has been alleviated since 2006 with a totally warming for 52 a; compared with global change, it has delayed for 8 a; precipitation has increased obviously in the plateau; climate wetting has delayed as compared with warming; 5 a short period precipitation variation has been not significant, instead of 12 a and 25 a period precipitation variation. With the greenhouse gas and aerosol increasing, plateau summer monsoon has enhanced, ENSO events and solar radiation has decreased, climate in the plateau has become warmer continuously but eased; plateau heating field has enhanced in spring and plateau summer monsoon has erupted early and kept strong, which lead to more rainfall in spring and summer, as well as the annual precipitation; yet in autumn and winter, AO has been relatively stable, east Asian trough intensity also has changed not obviously, as well as the plateau winter monsoon, as a result, precipitation in autumn and winter also has changed insignificantly. Temperature and precipitation in the plateau will be kept increasing in the future 20-40 years.
  • JI Qin, YANG Jianping, CHEN Hongju
    Journal of Glaciology and Geocryology. 2018, 40(6): 1090-1099. https://doi.org/10.7522/j.issn.1000-0240.2018.0415
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    Changes of precipitation, the seasonal distribution and pattern have always been one of the hotspots of global climate change research. From new perspectives of combinations of trend, fluctuation characteristics and extreme event, the changes of trend, fluctuation and extreme event of precipitation are analyzed using daily precipitation data from 72 meteorological stations on the Tibetan Plateau from 1961 to 2015. The following conclusions can be drawn:(1) Temporally, over the 55 years, the regional-averaged annual precipitation, maximum daily precipitation and the days when precipitation ≥ 10 mm had increased with the rates of 6.59 mm·(10a)-1, 0.33 mm·(10a)-1 and 0.26 d·(10a)-1, up to 36.2 mm, 1.8 mm and 1.4 d, respectively. (2) Spatially, over the 55 years, annual precipitation had increased in most areas of the Tibetan Plateau, along with an instability increase. But there were great regional differences in precipitation fluctuation variation. The annual precipitation fluctuation had increased slowly in the vast central and western regions, while in the eastern regions, the rapid increasing regions of and the rapid decreasing regions of precipitation fluctuation had alternatively distributed from north to south, and so did the extreme precipitation intensity and frequency. (3) The combination of trend, fluctuation characteristics and extreme changes had indicated that the future extreme precipitation events will likely increase obviously in the Qilian Mountains, the eastern Qaidam Basin, Qinghai Lake basin and source regions of the Yangtze River in the eastern part of the plateau, the probability of heavy precipitation will also increase in the central and western regions of the plateau, and the drought events will probably increase in the southeastern margin of the plateau.
  • LIANG Jingjing, ZHANG Bo, MA Bin, WEI Huaidong, ZHANG Jiaqi, MA Shangqian
    Journal of Glaciology and Geocryology. 2018, 40(6): 1100-1109. https://doi.org/10.7522/j.issn.1000-0240.2018.0412
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    According to the data of temperature and precipitation from 74 weather stations on the Tibetan Plateau from 1980 to 2014 and combining the Penman-Monteith formula, the evapotranspiration and the standardized precipitation evapotranspiration index (SPEI) have been calculated. The M-K trend analysis, mutation analysis and wavelet analysis have been used to analyze the spatial and temporal variation of SPEI on the Tibetan Plateau. The results show:(1) The daily SPEI based on the Penman-Monteith formula can well reflect the drought characteristics of the plateau. Since 1980, the SPEI on the plateau has increased, that is, partial to the wet and the drought intensity decreased. (2) The drought on the plateau in the past 35 years had obvious interdecadal variation, drought had been more severe before the 1990s; M-K mutation analysis showed that a mutation occurred in 1990, the severity and duration of drought had reduced after the 1990s. (3) Wavelet analysis revealed that there was a 2-4 years oscillation period of plateau drought. The dry-wet period had changed overall with a time scale of 2-4 years; there were three indicators in the 3.7 years primary period all passing 95% red noise test.
  • SHI Jiqing, GAN Chenlong, Bianduo, Chuduo, DOU Yongli, Pubu Ciren, GUO Yinan
    Journal of Glaciology and Geocryology. 2018, 40(6): 1110-1119. https://doi.org/10.7522/j.issn.1000-0240.2018.0120
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    The observations from 39 meteorological observation stations in Tibet Autonomous Region from 1981 through 2015 were analyzed in relation to season changing. The analyses include the initial date and the duration of various seasons, the extreme date and the extreme duration of various seasons, season sooner or later, season getting longer and shorter, including rating of their trends, as well as their change trend and impact on agriculture, animal husbandry and tourism. The results indicate that the 35 a average initial dates of spring, summer, autumn and winter are February 25th, May 31st, September 15th and November 28th, respectively. The 35 a average durations of the four seasons were 99 d, 106 d, 73 d and 87 d, respectively, with an obvious regional difference. The initial date of spring had been -5.8, -1.2, -3.3, 2.5 and 2.3 d·(10a)-1 sooner in Bomi, Jiacha, Nimu, Shiquanhe and Shenzha, respectively. The initial date of autumn (winter) had been later 1.4 (1.5), 2.1 (4.2), 1.9 (4.4), 1.0 (2.5) and 1.2 (4.0) d·(10a)-1 in Bomi, Jiacha, Nimu, Shiquanhe and Shenzha, respectively. The duration in spring (summer, autumn) had extended 7.0 (1.3, 0.1), 0.04 (3.3, 2.1), 1.0 (4.6, 2.5), 0.1 (3.4, 1.6) and 1.7 (1.8, 2.8) d·(10a)-1, respectively, in the five stations. The duration in winter had shortened 8.5, 5.4, 7.8, 5.1 and 6.2 d·(10a)-1, respectively, in the five stations. The advancing of spring and the extension of spring duration make the planting time and the herbage turning-green early; the postponement of autumn and shortening the autumn duration make the opportunity of replanting crops great; at the same time, it has a certain impact on the planting structure, the mature distribution of crop varieties, as well as on the tourism.
  • SHI Tenglong, CUI Jiecan, PU Wei, WANG Xin, ZHANG Xuelei
    Journal of Glaciology and Geocryology. 2018, 40(6): 1120-1132. https://doi.org/10.7522/j.issn.1000-0240.2018.0121
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    A new radiative transfer model (Spectral Albedo Model for Dirty Snow, or SAMDS) based on the asymptotic radiative transfer theory was applied to simulate the spectral albedo of snow due to different parameters, such as solar zenith angle, snow grain size, impurities concentrations, and mass absorption cross-section of impurities. The results show that the SAMDS model produced a snow broadband albedo in the range of 0.95~0.75 for fresh snow, with a snow grain optical effective radius increasing from 50 μm to 800 μm. The snow albedo for spherical snow grains is lower than that for the other two shapes. In addition, the variations of spectral albedo of snow in the infrared is mainly dominated by the snow grain size and by the solar zenith angle, also the snow grain shape has a slight effect. Nevertheless, the variations of spectral albedo of snow in the visible and ultraviolet bands is governed largely by the load of pollutants. Moreover, the simulated snow albedo by SAMDS agree well with the observed values. Simultaneously, the modeled broadband albedo decrease by 2%~8% due to 0.1~1 μg·g-1 of black carbon (BC) in snow with snow grain optical effective radius equal 250 μm, and the associated instantaneous radiative forcing were 9~35 W·m-2.
  • YANG Xiaoling, GUO Limei, ZHANG Chunyan, WANG Heling
    Journal of Glaciology and Geocryology. 2018, 40(6): 1133-1140. https://doi.org/10.7522/j.issn.1000-0240.2018.0503
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    Nowadays, it is urgent to improve forecast level of snowfall, to study regional climate change, to utilize scientifically water resources and to protect ecological environment in east Hexi Corridor. Using daily snow data from five meteorological stations in east Hexi Corridor during 1960-2016, temporal and spatial variations of snowy days in this region were analyzed with climatic statistics method. The results showed that temporal and spatial variations of snowy days had been decreased from southwest to northeast because of the effect of altitude, topography and weather system. Except for Liangzhou, annual and decadal snowy days had decreased, expecially in Tianzhu. Time series of annual snowy days had a six to eight years quasi-periodic variation. Temporally, monthly variation of snowy days had been rather consistent; snowy days mainly appeared from January to April and from October to December, with a peak in March, and winter was the primary snow season. Annual anomalism of snowy days was consistent every where, with an occurrence probability of 68.4%~73.7% normally, and declining to both ends in turn. Less snowy days had a high percentage of snowy days in east Hexi Corridor, with a occurrence probability of 78.6%~93.5% and decreasing rapidly with magnitude. Less snowy days of 0.0 mm had decreased significantly and had negatively contributed to total snowy days; less snowy days of ≥ 0.1 mm and middle snowy days had increased mostly and positively contributed to total snowy days; heavy snow days had weakly decreased mostly and had negatively contributed to total snowy days.
  • HU Wentao, YAO Tandong, YU Wusheng, YANG Wei, GAO Yang
    Journal of Glaciology and Geocryology. 2018, 40(6): 1141-1152. https://doi.org/10.7522/j.issn.1000-0240.2018.0504
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    Under the background of climate change, it is believed that the glacier avalanches will become a new normal in the Tibetan Plateau, which severely threatens the destiny of "the Asian Tower" and the ecological security of "the Third Pole". Consequently, to study the glacier avalanches in High Asia is of important significance for the human and the environment. In this paper, several glacier avalanches historically documented are presented and the development of glacier avalanches are introduced; the research content is summarized based on the material composition, motion characteristics, possible causes and impact of the glacier avalanches; the available research methods are presented; finally the existing problems in recent research on glacier avalanches are discussed and the research direction of glacier avalanches is prospected from the perspective of study methods.
  • QIN Yanhui, WU Tonghua, LI Ren, HU Guojie, QIAO Yongping, ZHU Xiaofan, YANG Shuhua, YU Wenjun, WANG Weihua
    Journal of Glaciology and Geocryology. 2018, 40(6): 1153-1166. https://doi.org/10.7522/j.issn.1000-0240.2017.0307
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    The knowledge of the thermal condition within the active layer is of great significance for understanding the variation characteristics of the active layer, the thermal effect of the upper underlying ground and for predicting climate change on the Qinghai-Tibet Plateau. In this paper, the GIPL2 model was used to simulate the soil thermal variations at different depths under different vegetation in permafrost regions over the Qinghai-Tibet Plateau. The simulated results indicate that the GIPL2 model has performed better at the alpine steppe observation site (QT06), but at the alpine swamp meadow observation site (QT03) it has performed bad; between both there are the alpine meadow observation site (QT01), the alpine desert steppe observation site (QT05) and the alpine steppe observation site (QT04). The root-mean-square errors at QT01, QT03, QT04, QT05 and QT06 are 0.67, 1.29, 0.73, 0.7 and 0.56℃, respectively; their correlation coefficients are 0.99, 0.87, 0.98, 0.98 and 0.96 and their mean bias errors are 0.37, 0.61, 0.31, 0.45 and 0.16℃, respectively. The GIPL2 model has better result at QT06, which probably results from the soil stratification used in the model is closer to real condition. The simulated results at QT03 is worse, which may be due to the existence of gravel in the soil and the thermal conductivity parameter in the model has not considered the gravel content. Overall, the GIPL2 model can simulate soil temperature of multiple soil layers in permafrost regions on the plateau. It means that the GIPL2 model could be used to simulate the thermal regime of the active layer of the permafrost on the Qinghai-Tibet Plateau.
  • WANG Ningning, ZHANG Hu, ZHANG Jianming, ZHAO Zhonghu, ZHOU Panfeng
    Journal of Glaciology and Geocryology. 2018, 40(6): 1167-1172. https://doi.org/10.7522/j.issn.1000-0240.2018.0125
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    Variation of pore-water pressure is a key to reveal the deformation mechanisms of soil under an external load. In order to study the property of pore-water pressure in warm frozen soil, compressive consolidation experiment under different temperatures and different drainage conditions have been carried out. The pore-water pressure and displacement at -1, -0.5 and -0.3℃ were monitored respectively. The results reveal that temperature has great effect on pore-water pressure and deformation of warm frozen soil. When the temperature is higher, the deformation rate of the soil, the peak pore-water pressure and the rate of dissipation are greater. At the same temperature, the peak pore-water pressure under drainage condition is lower than that under non-drainage condition, but the displacement is larger than the latter. It can be found from the results that the pore-water pressure is subjected to two actions simultaneously:increase caused by solid skeleton compression and slowly dissipation.
  • LI Jielin, LIU Hanwen
    Journal of Glaciology and Geocryology. 2018, 40(6): 1173-1180. https://doi.org/10.7522/j.issn.1000-0240.2018.0411
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    In this paper, the expansion mechanisms of pores in sandstone under freezing-thawing cycles were studied, and a volumetric deformation model of water frozen in the pores under saturated condition has been established based on the theory of elasticity and thermodynamics. By combining the change of porosity in the saturated sandstone and T2 spectrum distribution test results under the effect of freezing-thawing cycles by means of nuclear magnetic resonance, a volumetric deformation model has been established, thus the rule of pore volumetric deformation of sandstone due to freezing-thawing has been analyzed. The results show that the value of volume expansion coefficient of saturated sandstone under the effect of freezing-thawing cycles is more than 8.69%. The damage of once freezing-thawing to the sandstone sample is less, and the change of the pore volume is within the range of 0.80%-1.03%. It is found that the variation of the pore shrinkage coefficient and the proportion of the pore elastic deformation volume are consistent, both are increasing first and then decreasing. The pore shrinkage coefficient of sandstone is within the range of 7.92%-8.04%, and the average volume proportion of pore elastic deformation is 97.79%. In the process of freezing-thawing, the elastic deformation of large pores is less than that of small pores.
  • TAO Qi, WANG Yan
    Journal of Glaciology and Geocryology. 2018, 40(6): 1181-1186. https://doi.org/10.7522/j.issn.1000-0240.2018.0416
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    In this paper, the mechanical properties and frost resistance of magnesium phosphate cement (MPC) concrete under 20℃, -10℃, -15℃ and -20℃ has studied, in order to provide scientific basis for MPC concrete using in emergency repair engineering in cold and arid environment. The experimental method of MPC concrete mechanical properties was based on GB/T 50081-2002, and the experimental method of MPC concrete frost resistance was based on GB/T 50082-2009. The experiment results showed that under curing condition of 20℃, 28-d compressive strength of MPC concrete is 65.3 MPa and flexural strength is 6.8 MPa. Under curing condition of -10℃, 28-d compressive strength of MPC concrete is 59.7 MPa and flexural strength is 7.2 MPa. The mass loss ratio of MPC concrete is 3.5% and the relative dynamic elastic modulus of MPC concrete is 83.5% under curing condition of -10℃ after 300 fast freeze-thaw cycles. The MPC concrete frost resistance under curing condition of -10℃ is better than that under curing condition of 20℃. In conclusion, the mechanical properties and frost resistance of MPC concrete are excellent under curing condition of -10℃, which could be used in emergency repair engineering in cold and arid environment.
  • CHEN Hui, YANG Shengli, CHENG Ting, LIU Nannan, LI Shuai, LIANG Minhao, TANG Guoqian
    Journal of Glaciology and Geocryology. 2018, 40(6): 1187-1194. https://doi.org/10.7522/j.issn.1000-0240.2018.0507
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    The relationship between magnetic susceptibility (MS) and climatic factors in modern topsoil is of great importance for regional magnetic enhancement mechanisms and paleoclimate reconstruction, which has had significant advancement in the Loess Plateau but not in the Tibetan Plateau. 106 samples of topsoil have been collected in the eastern Tibetan Plateau and variations of their MS have been analyzed by using Bartington Instruments MS2 Magnetic Susceptibility Meter. In addition, the effects of climatic factors on the low-frequency magnetic susceptibility (χlf) and frequency-dependent magnetic susceptibility (χfd) of modern topsoil in the eastern plateau were discussed based on the correlations between surface magnetic susceptibility and climatic factors. Climate data of topsoil were calculated by ARCGIS-interpolation of the mean annual temperature (MAT) and precipitation (MAP) from 1981 through 2010 from 274 meteorological stations. The results showed that MS of topsoil in the study area is mainly depended on temperature and precipitation, as well as the difference in hydrothermal composition which affected the MS value of topsoil. χlf has a little relation with climatic factors also. In addition, the correlation of χlf with temperature is better than that with precipitation. χfd is more sensitive to the change of precipitation and has a positive correlation with precipitation. This has clear indication significance and can be used for quantitative reconstruction of paleo-precipitation in the eastern part of the Tibetan Plateau.
  • ZHOU Xianwei, ZHAO Yu, ZHU Yumei, LOU Dejun
    Journal of Glaciology and Geocryology. 2018, 40(6): 1195-1206. https://doi.org/10.7522/j.issn.1000-0240.2018.0417
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    Water vapor, thermal and dynamic conditions and mesoscale features of two snowstorm processes in Heilongjiang Province caused by the merger of Jiang-Huai cyclone and the Mongolian cyclone were compared and analyzed by using various data. The results show that:(1) The two snowstorms occurred in the merger of the north branch trough and the shortwave trough, and then a cold vortex formed in the north of the north branch trough, the low vortex combined at 850 hPa, resulting in a merger of the Jiang-Huai cyclone and the Mongolian cyclone; after the cyclone merged, the low-level jet stream provided sufficient water vapor for the snowfall, and the strong warm advection made the cyclone explosively developing and strengthening the snowfall. (2) Comma cloud system developed combinedly in the two snowfalls. A high-level vortex formed by west during the "1211" snowstorm. The southerly wind in the eastern part of the 700 hPa low vortex guided the cyclone northwards and west-northwestwards. The eastward wind of 700 hPa low vortex southerly guided the cyclone north to the west, and the low-level jet stream and the topography worked together to make the warm and humid air rise strongly, resulting in convective clouds. Snowstorm occurred at the head of a A-type comma cloud system, and had a large snowfall intensity and a wide range; in the "1412" snowstorm case, the high-altitude trough low-vortex position was eastwards, and the 700 hPa low-vortex east-west wind always guided the cyclone to move to the northeast. There was a cold wedge in the near ground layer. Snowstorm mainly occurred in the middle and low cloud clusters on the west side of the head of the B-type cyclone comma cloud system, and the snowfall range and intensity were smaller than the "1211" cases. (3) The cold air of the lower layer (0.3 km) invasion and the transition of the upper layer (5.5 km) to the northerly wind had a good representational significance for judging whether the snowfall starts and ends. (4) The strong ridges in the front of the cold vortex moved the cold vortex slowly, which prolonged the duration of precipitation, and the cyclone moving path closely related to its direction.
  • XU Junli, LIU Shiyin, WANG Jian
    Journal of Glaciology and Geocryology. 2018, 40(6): 1207-1215. https://doi.org/10.7522/j.issn.1000-0240.2018.0419
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    The acceleration of the rock glacier movement due to global warming means that the ability to move gravels (material source of debris flow) downstream is increased. Due to the warming of the climate, the rock glacier may be an important future cause of the cryosphere disaster. With the continuous development of socio-economic and technological level, the scope of human activities is constantly expanding, more and more engineering projects are being advanced to remote high-altitude mountainous areas, which face the problem of glaciers and rock glaciers inevitably. It is important to monitor the distribution of rock glaciers in the upper reaches of the Bayu Hydropower Station. Therefore, our study uses GEOeye-1 remote sensing images with 0.5 m resolution to identify the distribution information of rock glaciers upstream of Bayu Hydropower Station by artificial interpretation through the unique texture features of the glacier combined with the slope information extracted by SRTM. It concludes that:(1) The upstream glacier in the proposed Bayu Hydropower Station is concentrated on the north side of the Yarlung Zangbo River with a total of 27 rock glaciers, covering an area of 12.2±0.9 km2 with an average area of 0.5 km2, and an average length of 1 456 m, and an average width of 280 m. (2) The rock glaciers are located at an elevation of 4 570 m to 5 720 m with an average terminal elevation of 4 920 m. Most rock glaciers are tongue-shaped. Thirteen (about 1/2) rock glaciers are in the active period, of which 5 rock glaciers collapsed terminally, will lead to debris flow and other large disasters.
  • ZHANG Lele, GAO Liming, CHEN Kelong
    Journal of Glaciology and Geocryology. 2018, 40(6): 1216-1222. https://doi.org/10.7522/j.issn.1000-0240.2018.0418
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    Based on the solar radiation data observed from May 2014 to November 2015 in the Wayanshan Wetland, Qinghai Lake watershed, a comprehensive analysis of the solar radiation was made in this study. The results showed that the maximum net radiation and global radiation in the Wayanshan Wetland appeared in July and the minimum values appeared in December. The maximum atmospheric long-wave radiation appeared in August and the minimum value appeared in December. The maximum ground long-wave radiation appeared in July and the minimum value appeared in February. The cloudy day had obviously decreased the global radiation and obviously increased the atmospheric long-wave radiation, but to net radiation and ground long-wave radiation it had different effect in different seasons, with great seasonal difference in ground long-wave radiation and net radiation. The annual average value of surface albedo in the Wayanshan Wetland was 0.26. Under no snow cover condition, the surface albedo in freezing period was significantly greater than that in ablation period, with the maximum value appeared in December. The average value of summer surface albedo in Wayanshan Wetland was 0.185, much smaller than that in Tanggula Station. The underlying surface of the two stations was all meadow. In warm season, soil moisture was also an important factor affecting surface albedo of alpine wetland, and albedo decreased with increase of soil water content.
  • ZHANG Haihong, SU Yongling, JIANG Haimei, CHAO Hongyan, SU Wenjiang
    Journal of Glaciology and Geocryology. 2018, 40(6): 1223-1230. https://doi.org/10.7522/j.issn.1000-0240.2018.0420
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    Using the observed data at Longbao, Yushu, Qinghai in Dec. 2014, influence of snow subliming process on land-atmosphere interaction were analyzed. The results show that shallow soil temperature increases in a short time during snow falling and subliming. Responses of deep soil temperature and soil moisture to snowfall are insensitive. Daily averages of net radiation, sensible heat flux and latent heat flux increase during snow subliming process. Daily average of upward shortwave radiation decreases during snow subliming process. The energy absorbed by ground and transferred to atmosphere both increases on account of snow subliming. Sensible heat ratio (H/Rn) and latent heat ratio (LE/Rn) increase while soil heat flux ratio (G/Rn) and heat storage ratio (S/Rn) decrease along with snow subliming process. Surface albedo and surface emissivity increase but sensible heat transfer coefficient decreases with snow cover depth increasing.
  • DU Yahan, ZHOU Shunwu, Hengbati, LI Yaohui, WANG Tie, SONG Yao
    Journal of Glaciology and Geocryology. 2018, 40(6): 1231-1241. https://doi.org/10.7522/j.issn.1000-0240.2018.0133
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    According to the daily precipitation data collected from 51 stations in Xinjiang during the recent 51 years (1965-2015), the precipitation intensity can be classified into three levels:light rain; moderate rain and heavy rain. The spatial patterns of the three-level precipitation amounts, precipitation days, and precipitation intensity during summers of the 51 years in the area were analyzed, we discuss their spatial pattern differences of total precipitation through spatial correlation coefficient calculation and the contribution of precipitation at different levels to summer total precipitation. Results show as follows:(1) The precipitation occurred most frequently in summer, and the light rain was the major of this area. Taking Tianshan Mountains as the boundary, there was significant differences in the spatial distribution of precipitation in the north and south Xinjiang, the summer precipitation amounts (precipitation days) in North Xinjiang accounted for 36%~45% (36%~39%) of annual precipitation amounts(precipitation days), and in South Xinjiang accounted for 51%~63% (48%~60%) of annual precipitation amounts (precipitation days); (2) The spatial distribution of amount, days and intensity for different grades of precipitation in Xinjiang were uneven. The spatial correlation coefficient of summer total precipitation and the precipitation amounts of each grades was most closely, with the precipitation intensity of each grades were relatively poor; (3) The contribution rate of Xinjiang summer precipitation mainly was light rain, the moderate rain took the second place, and the heavy rain ranked the third. The change of precipitation amounts and precipitation days in summer was mainly affected by light rain.
  • JING Mingbo, WANG Jincheng, DUAN Chunyan, YANG Ruiqi, REN Peng, WU Shengwei
    Journal of Glaciology and Geocryology. 2018, 40(6): 1242-1254. https://doi.org/10.7522/j.issn.1000-0240.2018.0414
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    In order to further understand the environmental factor response mechanisms of crude-oil contaminated soil ecological remediation by using cold-tolerance degrading microbial agent under low temperature stress in eastern Gansu, an experiment based on the cold-tolerance degrading bacteria agent had been selected to do the ecological remediation of crude-oil contaminated soil for 7 months at Longdong oil sludge treatment station of Changqing Oilfield Company in Qingyang Prefecture of Gansu Province, and the changes and seasonal response of environmental factors to the ecological remediation in soil physicochemical properties, enzyme activity and microbial community properties were investigated using the conventional methods. The results showed that:(1) Cold-tolerance degrading microbial agent group (M2, cold-tolerance degrading microbial agent) demonstrated a higher crude oil degradation rate (28.64%±4.12%) than that of the group of room temperature degrading microbial agent combined Calendula officinalis (JZJ+M1) (15.37%±3.51%) from September to November (P<0.01). (2) The activity of soil dehydrogenase and polyphenol oxidase of M2 was the highest in the low temperature season (LT), with an obvious interaction between treatment and temperature (P<0.01). In terms of soil nutrient elements, the content of both methods (JZJ+M1 and M2) were both higher than that of LT (P<0.05) and significantly higher than that in CK group (P<0.05). (3) Index of soil microbial community Shannon-Wiener and evenness index in Group M2 also demonstrated a higher level in the cold temperature season than that in room temperature season (P<0.05). (4) Nonmetric multidimensional scaling (NMDS) analysis suggested that Group M2 in cold temperature season demonstrated a higher crude oil degradation rate, which were strongly affected by activity of soil dehydrogenase and polyphenol oxidase, Shannon-Wiener index of soil microbial community, as well as showing a positive correlation with monthly TPH degradation rate (μ2). This work was aimed to optimize and accelerate soil TPH degradation rate for ecological remediation under low temperature stress via analyzing environmental factors responses to ecological remediation of crude-oil contaminated soil, as well as to offer the basic data to application of cold-tolerance degrading microbial agent in Longdong Loess Plateau.
  • ZHANG Tao, WANG Genxu, YANG Yan, MAO Tianxu
    Journal of Glaciology and Geocryology. 2018, 40(6): 1255-1264. https://doi.org/10.7522/j.issn.1000-0240.2018.0135
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    The ecosystem respiration (ER) of various vegetation and in various seasons is very important for accurate estimation of CO2 emissions in the Qinghai-Tibet Plateau. The ER had been measured of alpine meadow and swamp meadow in different seasons in 2013 on Fenghuoshan Mountain in the permafrost regions of the Qinghai-Tibet Plateau. ER diurnally and seasonally varied significantly in the two meadows; the diurnal variable coefficient of alpine meadow (0.30~0.92) was higher than that of swamp meadow (0.12~0.29); the seasonal variations of ER changed dynamically with soil temperature (for example, at 5 cm depth). The mean ER was 0.31 and 0.36 mol·m-2·s-1 in non-growing season and 1.99 and 2.85 mol·m-2·s-1 in growing season in alpine meadow and swamp meadow, respectively. The annual emission of ER was higher in swamp meadow (1 419.01 gCO2·m-2) than that in alpine meadow (1 042.99 gCO2·m-2), the former was 27% higher than the latter in non-growing season and 39% higher than the latter in non-growing season, respectively. ER in non-growing season was 268.13 and 340.40 gCO2·m-2 in alpine meadow and swamp meadow, respectively, contributed to 25.71% and 23.99% of annual ER. Of both meadows, the ER was correlated significantly to air temperature, as well as soil temperature, for example, at 5 cm and 20 cm depths, account for 37%~73% of seasonal variations. It was found that a highest correlation between ER and soil temperature at 5 cm depth, expect for the swamp meadow in growing season. There was no significant relationship between ER and soil moisture in the growing season, but there was a positive relationship (R2:0.21~0.40) in non-growing season. The Q10 corresponding to the ground temperature of 5 cm in the non-growing season was 4.34~5.02, higher than that in the growing season (2.35~2.75), and that in swamp meadow higher than that in alpine meadow. There was no significant relationship between ER and soil moisture in the growing season, but ER in the non-growing season was significantly affected by soil moisture (R2:0.21~0.40), increasing with soil moisture.
  • WEI Yaxi, YANG Yongsheng, HE Huidan, ZHU Jingbin, LI Hongqin, LI Yingnian
    Journal of Glaciology and Geocryology. 2018, 40(6): 1265-1274. https://doi.org/10.7522/j.issn.1000-0240.2018.0136
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    Soil physicochemical properties and metallic elements were analyzed under three grassland types in the middle and east of Qinghai-Tibet Plateau, aiming to provide basic data for "intelligent" and "high quality" animal by-products and "farm-animal coupling" model optimization. The results showed that (1) the coverage of vegetation was ordered as kobresia pygmaea meadow (91%) > meadow grassland (85%) > warm steppe (75%), and the maximum number of species occurred in meadow grassland, reaching 25 kinds, which was 1.89 and 1.40 times as much as k. pygmaea meadow and meadow grassland, respectively. (2) The soil bulk density of warm steppe was 1.89 and 1.40 times than k. pygmaea meadow and meadow grassland in 0~10 cm depth, and was 1.42 and 1.29 times than k. pygmaea meadow and meadow grassland in 10~20 cm depth, respectively. (3) The soil organic matter and total nitrogen were the highest in k. pygmaea meadow soil, for example, the content of organic matter was 1.20 and 2.65 times than meadow grassland and warm steppe, and the total nitrogen content was 1.18 and 2.47 times than meadow grassland and warm steppe, respectively. However, the soil pH value reaching the top point in warm steppe, with 8.46, was 1.04 and 1.10 times than meadow grassland and k. pygmaea meadow. (4) The peak of heavy metals content occurred in Kobresia meadow, next came meadow grassland and then the lowest point occurred in temperate grassland. In general, the contents of heavy metal elements analyzed in soils with three different grassland can be defined as the first-class safety standard, indicating those regions were suitable for developing organic livestock production.
  • DU Yu'e, LIU Baokang, HE Weiguo, ZHOU Jianping, DUAN Shuiqiang
    Journal of Glaciology and Geocryology. 2018, 40(6): 1275-1284. https://doi.org/10.7522/j.issn.1000-0240.2019.0304
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    The plateau lakes are sensitive indicators of climate change. The variation of lake area were monitored by using multi-source satellite data from 1976 to 2017 in the Qaidam Basin. The results show that the climate of the basin had been warming and humidifying in the 50 years, especially since 2000. The rising rate of annual average temperature had increased from east to west, and the increasing rate of precipitation had decreased from east to west. The Torsu Lake in the eastern part of the basin had less decreased from 1956 to 2017, with a rate of -0.41 km2·a-1. However, during the period of 2005-2017, the lake surface had expanded at a rate of 1.34 km2·a-1. The area of Xiaochaidan Lake in the basin middle had increased 19.87 km2 as compared with that in the past 13 years; while the area of the western Gaskule Lake had increased first and then decreased. Climate change, variations of vegetation area and lake runoff and human activity are the main causes of lake area change in Qaidam Basin.
  • CHEN Li, LI Shuai
    Journal of Glaciology and Geocryology. 2018, 40(6): 1285-1290. https://doi.org/10.7522/j.issn.1000-0240.2018.0138
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    Blowout and leak of heat-supply pipe are popular in urban centralized heating system. Large heat-supply network failure often occurs in the depth of winter. If the period of no heat-supply or limited heat-supply for repairing the network is too long, it will cause serious social and economic impact. At the same time, the energy supply might be lack if weather keeps extreme cold. In order to strengthen the risk assessment and emergency management capability, it is necessary to offer a method of quantitative assessment on energy for heating and methods of meteorological risk assessment on energy supply and heat network maintenance. The energy supply risk is followed by a normal distribution. Formulas are proposed to describe the cold risk level corresponding to the period of heat network maintenance in this paper. Future more, some risk assessment cases are provided.