The degree-day model is one important method to estimate glacier melt, which is based on the specific relationship between glacial melting and the sum of daily mean temperatures above the melting point. According to t...The degree-day model is one important method to estimate glacier melt, which is based on the specific relationship between glacial melting and the sum of daily mean temperatures above the melting point. According to the observation data on the Koxkar Glacier(KG) from 2005 to 2010, we analyzed the temporal and spatial variation of degree-day factors(DDF) and its influential factors. The results indicate that the average value of DDF was 7.2~10.4 mm/(°C·d) on the KG from 2005 to 2010. It showed a decreasing trend between 3,700 m and 4,200 m, and the deceasing trend was more obvious in the upper part of the KG. On a spatial scale, the DDF increased evidently with increasing altitude. The DDF ranged from3.6 to 9.3 mm/(°C·d) at 3,700 m a.s.l., with the average value of 9.3 mm/(°C·d). It varied from 6.9 to 13.0 mm/(°C·d) at4,000 m a.s.l., with the average value of 10.2 mm/(°C·d). During the period of ablation, the fluctuation of DDF was not significant at the lower altitude(3,700 m a.s.l.), but it decreased at the higher altitudes(4,000 m a.s.l. and 4,200 m a.s.l.).The debris changes the transmission of heat, which accelerates the melting of a glacier; and the DDF showed high value.This paper will provide the reference for temporal–spatial parameterization schemes of DDF on Tuomuer glaciers of the Tianshan Mountains.展开更多
By using a degree-day based distributed hydrological model, regimes of glacial runoff from the Koxkar glacier during 2007-2011 are simulated, and variations and characteristics of major hydrological components are dis...By using a degree-day based distributed hydrological model, regimes of glacial runoff from the Koxkar glacier during 2007-2011 are simulated, and variations and characteristics of major hydrological components are discussed. The results show that the meltwater runoff contributes 67.4%, of the proglacial discharge, out of which snowmelt, clean ice melting, buried-ice ablation and ice-cliff backwasting account for 22.4%, 21.9%, 17.9% and 5.3% of the total melt runoff, respectively. Rainfall runoff is significant in mid-latitude glacierized mountain areas like Tianshan and Karakorum. In the Koxkar glacier catchment, about 11.5% of stream water is initiated from liquid precipitation. Spatial distributions for each glacial runoff component reveal the importance of climatic gradients, local topography and morphology on glacial runoff generation, and temporal variations of these components is closely related to the annual cycle of catchment meteorology and glacier storage. Four stages are recognized in the seasonal variations of glacier storage, reflecting changes in meltwater yields, meteorological conditions and drainage systems in the annual hydrological cycle.展开更多
Hydrology of the high glacierized region in the Tianshan Mountains is an important water resource for arid and semiarid areas of China,even Central Asia.The hydrological process is complex to understand,due to the hig...Hydrology of the high glacierized region in the Tianshan Mountains is an important water resource for arid and semiarid areas of China,even Central Asia.The hydrological process is complex to understand,due to the high variability in cli mate and the lack of hydrometeorological data.Based on field observations,the present study analyzes the meteorological and hydrological characteristics of the Koxkar Glacier River Basin during 20082011;and the factors influencing climate impact on glacier hydrology are discussed.The results show that precipitation at the terminus of the glacier was 426.2 mm,471.8 mm,624.9 mm,and 532 mm in 2008,2009,2010,and 2011,respectively.Discharge increases starting in May,reaches its highest value in July and August,and then starts to decrease.The mean annual discharge was 118.23×106 m3 during the four years observed,with 87.0%occurring in the ablation season(May September).During the study period,the runoff in August accounted for 29%of total streamflow,followed by July(22%)and June(14%).The runoff exhibited obviously high interannual variability from April to September,induced by drastic changes in climate factors.Discharge autocorrelations are very high for all the years.The climate factors show different influences on discharge.The highest correlation R between daily temperature and discharge was for a time lag of 23 days 2on the Koxkar Glacier(0.660.76).The daily depth of runoff to daily temperature and daily water vapor pressure had an R value of 0.56 and 0.69,respective ly,which could be described by an exponential function.A closer relationship is found between runoff and either tempera ture or water vapor pressure on a monthly scale;the R2 values are 0.65 and 0.78,respectively.The study helps us to under stand the mechanisms of the hydrological meteorological system of typical regional glaciers and to provide a reference for glacier-runoff simulations and water-resource management.展开更多
Various water samples were collected for electrical conductivity (EC) and δ^18O analysis,and the proportion and contribution of atmospheric precipitation,glacier ice and shallow groundwater to discharge in the Koxkar...Various water samples were collected for electrical conductivity (EC) and δ^18O analysis,and the proportion and contribution of atmospheric precipitation,glacier ice and shallow groundwater to discharge in the Koxkar glacier basin at the south slope of the Tianshan Mountains were studied.The results show that glacial ice-water recharge was dominant,accounting for 72.11% of the annual runoff.It also had a significant positive correlation with temperature during the warm season (from May to September).However,glacier ice ablation replenishment still existed when the temperature in the cold season was below the critical temperature of 0 ℃.This could be that the heat generated by the friction between the ice body and the ice bed during the subglacial ice sliding process led ice to melt,what's more,the stored water in the geometric passages inside and below the glacier could slowly release.Groundwater recharge accounted for 16.38% of the total runoff.The supplement was small and its variation range was relatively small in the cold season.But in the warm season,the amount of groundwater recharge increased and changed drastically.It might be that the seasonal frozen soil in the basin was widely developed and was affected by temperature changes.Atmospheric precipitation replenishment only accounted for 11.51%.The daily precipitation recharge river water had a significant response to regional precipitation,but there was hysteresis in time,and there was still precipitation recharge runoff even in the absence of precipitation.展开更多
We use multi-frequency ground penetrating radar （GPR） to detect and map debris thickness and shallow layer structure of buried ice-body under debris-covered. The basis analysis is depend on mainly （1） the stacking...We use multi-frequency ground penetrating radar （GPR） to detect and map debris thickness and shallow layer structure of buried ice-body under debris-covered. The basis analysis is depend on mainly （1） the stacking wave velocity in a common mid-point （CMP） survey, （2） the ratio of attenuation of an electromagnetic wave passing through different media, and （3） the vertical resolu- tion. Through a series of analysis, it was found that the optimal average velocity in the shallow layer （0-4 m） is 0.06 m/ns. Images obtained with antennas having different frequencies have different char- acteristics; i.e., the 50 MHz antenna provides much worse vertical resolution than the 200 and 100 MHz antennas （90 and 160 ns, respectively） and the performance of the 200 MHz antenna for a debris-covered glacier is best. This study provides the basis for accurate analysis of the structure and thickness of the debris layer in the zone of ablation of a debris-covered glacier, this study also provides a reference for research into the formation mechanism and estimation of the ice volume of glacier covered by debris.展开更多
基金supported by the National Natural Science Foundation of China (41501073, 41471060, 41421061)the project of State Key Laboratory of Cryospheric Science (SKLCS-ZZ-2017)China Postdoctoral Science Foundation (2015M580893, 2016T90966)
文摘The degree-day model is one important method to estimate glacier melt, which is based on the specific relationship between glacial melting and the sum of daily mean temperatures above the melting point. According to the observation data on the Koxkar Glacier(KG) from 2005 to 2010, we analyzed the temporal and spatial variation of degree-day factors(DDF) and its influential factors. The results indicate that the average value of DDF was 7.2~10.4 mm/(°C·d) on the KG from 2005 to 2010. It showed a decreasing trend between 3,700 m and 4,200 m, and the deceasing trend was more obvious in the upper part of the KG. On a spatial scale, the DDF increased evidently with increasing altitude. The DDF ranged from3.6 to 9.3 mm/(°C·d) at 3,700 m a.s.l., with the average value of 9.3 mm/(°C·d). It varied from 6.9 to 13.0 mm/(°C·d) at4,000 m a.s.l., with the average value of 10.2 mm/(°C·d). During the period of ablation, the fluctuation of DDF was not significant at the lower altitude(3,700 m a.s.l.), but it decreased at the higher altitudes(4,000 m a.s.l. and 4,200 m a.s.l.).The debris changes the transmission of heat, which accelerates the melting of a glacier; and the DDF showed high value.This paper will provide the reference for temporal–spatial parameterization schemes of DDF on Tuomuer glaciers of the Tianshan Mountains.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences under Grant No. KZCX2-YW-GJ04National Nature Science Foundation of China (NSFC) under Grant Nos. 41130641 and 41271078
文摘By using a degree-day based distributed hydrological model, regimes of glacial runoff from the Koxkar glacier during 2007-2011 are simulated, and variations and characteristics of major hydrological components are discussed. The results show that the meltwater runoff contributes 67.4%, of the proglacial discharge, out of which snowmelt, clean ice melting, buried-ice ablation and ice-cliff backwasting account for 22.4%, 21.9%, 17.9% and 5.3% of the total melt runoff, respectively. Rainfall runoff is significant in mid-latitude glacierized mountain areas like Tianshan and Karakorum. In the Koxkar glacier catchment, about 11.5% of stream water is initiated from liquid precipitation. Spatial distributions for each glacial runoff component reveal the importance of climatic gradients, local topography and morphology on glacial runoff generation, and temporal variations of these components is closely related to the annual cycle of catchment meteorology and glacier storage. Four stages are recognized in the seasonal variations of glacier storage, reflecting changes in meltwater yields, meteorological conditions and drainage systems in the annual hydrological cycle.
基金supported by the National Natural Science Foundation of China(41971094,41871055,41871059)a project of the State Key Laboratory of Cryospheric Science(SKLCS-ZZ-2019)+1 种基金the Youth Innovation Promotion Association CAS(2019414)the CAS Pioneer Hundred Talents Program(Xiaoming Wang)
文摘Hydrology of the high glacierized region in the Tianshan Mountains is an important water resource for arid and semiarid areas of China,even Central Asia.The hydrological process is complex to understand,due to the high variability in cli mate and the lack of hydrometeorological data.Based on field observations,the present study analyzes the meteorological and hydrological characteristics of the Koxkar Glacier River Basin during 20082011;and the factors influencing climate impact on glacier hydrology are discussed.The results show that precipitation at the terminus of the glacier was 426.2 mm,471.8 mm,624.9 mm,and 532 mm in 2008,2009,2010,and 2011,respectively.Discharge increases starting in May,reaches its highest value in July and August,and then starts to decrease.The mean annual discharge was 118.23×106 m3 during the four years observed,with 87.0%occurring in the ablation season(May September).During the study period,the runoff in August accounted for 29%of total streamflow,followed by July(22%)and June(14%).The runoff exhibited obviously high interannual variability from April to September,induced by drastic changes in climate factors.Discharge autocorrelations are very high for all the years.The climate factors show different influences on discharge.The highest correlation R between daily temperature and discharge was for a time lag of 23 days 2on the Koxkar Glacier(0.660.76).The daily depth of runoff to daily temperature and daily water vapor pressure had an R value of 0.56 and 0.69,respective ly,which could be described by an exponential function.A closer relationship is found between runoff and either tempera ture or water vapor pressure on a monthly scale;the R2 values are 0.65 and 0.78,respectively.The study helps us to under stand the mechanisms of the hydrological meteorological system of typical regional glaciers and to provide a reference for glacier-runoff simulations and water-resource management.
基金Supported by the National Natural Science Foundation of China(41471060,41401084,41730751 and 41871055)
文摘Various water samples were collected for electrical conductivity (EC) and δ^18O analysis,and the proportion and contribution of atmospheric precipitation,glacier ice and shallow groundwater to discharge in the Koxkar glacier basin at the south slope of the Tianshan Mountains were studied.The results show that glacial ice-water recharge was dominant,accounting for 72.11% of the annual runoff.It also had a significant positive correlation with temperature during the warm season (from May to September).However,glacier ice ablation replenishment still existed when the temperature in the cold season was below the critical temperature of 0 ℃.This could be that the heat generated by the friction between the ice body and the ice bed during the subglacial ice sliding process led ice to melt,what's more,the stored water in the geometric passages inside and below the glacier could slowly release.Groundwater recharge accounted for 16.38% of the total runoff.The supplement was small and its variation range was relatively small in the cold season.But in the warm season,the amount of groundwater recharge increased and changed drastically.It might be that the seasonal frozen soil in the basin was widely developed and was affected by temperature changes.Atmospheric precipitation replenishment only accounted for 11.51%.The daily precipitation recharge river water had a significant response to regional precipitation,but there was hysteresis in time,and there was still precipitation recharge runoff even in the absence of precipitation.
基金supported by the Chinese Glacier Inventory(Nos.2008DFA20400 and 2012M521817)
文摘We use multi-frequency ground penetrating radar （GPR） to detect and map debris thickness and shallow layer structure of buried ice-body under debris-covered. The basis analysis is depend on mainly （1） the stacking wave velocity in a common mid-point （CMP） survey, （2） the ratio of attenuation of an electromagnetic wave passing through different media, and （3） the vertical resolu- tion. Through a series of analysis, it was found that the optimal average velocity in the shallow layer （0-4 m） is 0.06 m/ns. Images obtained with antennas having different frequencies have different char- acteristics; i.e., the 50 MHz antenna provides much worse vertical resolution than the 200 and 100 MHz antennas （90 and 160 ns, respectively） and the performance of the 200 MHz antenna for a debris-covered glacier is best. This study provides the basis for accurate analysis of the structure and thickness of the debris layer in the zone of ablation of a debris-covered glacier, this study also provides a reference for research into the formation mechanism and estimation of the ice volume of glacier covered by debris.
