基于VIC_glacier模型的拉萨河水文模拟及冰川径流研究

拉萨河作为青藏高原南部雅鲁藏布江最大的支流,冰川融水是其径流的重要组成部分。本文基于VIC模型和度日模型构建的VIC_glacier模型,模拟了1990—2010年拉萨河流域径流过程。结果表明:(1)与VIC模型相比,VIC_glacier模型在研究区的径流模拟效果更好,日径流模拟值与观测值的相关系数接近0.8,纳什效率系数在0.75以上;(2)从上游到下游,冰川融水对径流的贡献率分别为21.4%(旁多站)、17.7%(唐加站)、14.5%(拉萨站),呈逐渐减少趋势;(3)冰川径流和非冰川径流年内变化均呈现“单峰型”形态,且在8月份达到峰值;(4)1990—2010年间,年冰川径流量整体呈现上升趋势,与同期气温上升的变化规律一致;年冰川融水对径流的贡献率与年降水量呈反比关系。研究成果可为拉萨河流域的水资源管理提供参考。

Adaptation models of mountain glacier tourism to climate change: a case study of Mt. Yulong Snow scenic area

Mountain glaciers have an obvious location advantage and tourist market condition over polar and high latitude glaciers. Due to the enormous economic benefit and heritage value, some mountain glaciers will always receive higher attention from commercial media, government departments and mountain tourists in China and abroad. At present, more than 100 glaciers have been devel- oped successfully as famous tourist destinations all over the world. However, global climate change seriously affects mountain glaciers and its surrounding environment. According to the current accelerated retreat trend, natural and cultural landscapes of some glaciers will be weakened, even disappear in the future. Climate change will also inevitably affect mountain ecosystems, and tourism routes under ice and glacier experience activities in these ecosystems. Simultaneously, the disappearance of mountain glaciers will also lead to a clear reduction of tourism and local economic benefits. Based on these reasons, this paper took Mr. Yulong Snow scenic area as an example and analyzed the retreat trend of a typical glacier. We then put forward some scientific and rational response mechanisms and adaptation models based on climate change in order to help future sustainable development of mountain glacier tourism.

Coupled 2D Hydrodynamic and Sediment Transport Modeling of Megaflood due to Glacier Dam-break in Altai Mountains,Southern Siberia

One of the largest known megafloods on earth resulted from a glacier dam-break,which occurred during the Late Quaternary in the Altai Mountains in Southern Siberia.Computational modeling is one of the viable approaches to enhancing the understanding of the flood events.The computational domain of this flood is over 9460 km2 and about 3.784 × 106 cells are involved as a 50 m × 50 m mesh is used,which necessitates a computationally efficient model.Here the Open MP(Open Multiprocessing) technique is adopted to parallelize the code of a coupled 2D hydrodynamic and sediment transport model.It is shown that the computational efficiency is enhanced by over 80% due to the parallelization.The floods over both fixed and mobile beds are well reproduced with specified discharge hydrographs at the dam site.Qualitatively,backwater effects during the flood are resolved at the bifurcation between the Chuja and Katun rivers.Quantitatively,the computed maximum stage and thalweg are physically consistent with the field data of the bars and deposits.The effects of sediment transport and morphological evolution on the flood are considerable.Sensitivity analyses indicate that the impact of the peak discharge is significant,whilst those of the Manningroughness,medium sediment size and shape of the inlet discharge hydrograph are marginal.

喜马拉雅山入湖冰川物质变化研究综述

入湖冰川在喜马拉雅山地区广泛分布,其快速消融和末端崩解,是该地区冰湖溃决洪水最重要的触发因子和影响因素。近年来入湖冰川整体处于物质持续且加速亏损状态,1975—2000年入湖冰川物质平衡为-0.33±0.07 m w.e.·a^(-1),近10 a达到-0.56±0.08 m w.e.·a^(-1),其平均物质损失速率-0.45±0.08 m w.e.·a^(-1)。入湖冰川物质损失速率明显高于其他类型冰川,末端消融及崩解是其主要原因。当前冰川末端水下物质损失仍无法准确估算,广泛应用于入海冰川末端消融模拟的羽流模型,为估算入湖冰川末端湖-冰物/热交换过程研究提供了可行方法,其中冰下融水径流量、冰川末端切面形态、湖水温度和密度是影响羽流模型估算结果的重要参数。基于羽流模型评估冰川末端水下消融特征,为准确评估未来情境下冰川物质变化奠定基础。

Glacier mass balance and its impacts on streamflow in a typical inland river basin in the Tianshan Mountains, northwestern China

Glaciers are known as natural ’’solid reservoirs’ ’, and they play a dual role between the composition of water resources and the river runoff regulation in arid and semi-arid areas of China. In this study, we used in situ observation data from Urumqi Glacier No. 1, Xinjiang Uygur Autonomous Region, in combination with meteorological data from stations and a digital elevation model, to develop a distributed degree-day model for glaciers in the Urumqi River Basin to simulate glacier mass balance processes and quantify their effect on streamflow during 1980–2020. The results indicate that the mass loss and the equilibrium line altitude(ELA) of glaciers in the last 41 years had an increasing trend, with the average mass balance and ELA being-0.85(±0.32) m w.e./a(meter water-equivalent per year) and 4188 m a.s.l., respectively. The glacier mass loss has increased significantly during 1999–2020, mostly due to the increase in temperature and the extension of ablation season. During 1980–2011, the average annual glacier meltwater runoff in the Urumqi River Basin was 0.48×108 m3, accounting for 18.56% of the total streamflow. We found that the annual streamflow in different catchments in the Urumqi River Basin had a strong response to the changes in glacier mass balance, especially from July to August, and the glacier meltwater runoff increased significantly. In summary, it is quite possible that the results of this research can provide a reference for the study of glacier water resources in glacier-recharged basins in arid and semi-arid areas.

天山南坡阿克苏流域冰川物质平衡及其融水径流对气候变化的响应研究

冰川融水是西北干旱区水资源重要组成部分,定量评估其变化对中、下游生态环境保护和工农业经济可持续发展具有重要意义。本文基于国家气象台站日降水和气温资料、数字高程模型(DEM)以及第一次冰川编目数据,利用度日模型模拟了天山南坡阿克苏流域1957—2017年冰川物质平衡及其融水径流变化,分析了融水径流组成及其对气候变化的响应。结果表明:1957—2017年流域年平均物质平衡为-94.6 mm w.e.,61年累积物质平衡为-5.8 m w.e.。流域冰川物质平衡线呈显著上升趋势,年均上升速率为1.6 m/a。研究区年均融水径流量为53.1×10^(8)m^(3),融水增加速率为0.24×10^(8)m^(3)/a,融水径流及其组成分量均呈显著增加趋势。在气候暖湿化背景下,流域降水的增加使得冰川区积累量增加,在剧烈的升温作用下,冰川消融加剧,气温对融水径流的作用增大,因此冰川物质平衡亏损产生的水文效应增强。研究结果可提升区域冰川水资源效应变化及其影响的认识。

表碛覆盖型冰川参数提取方法研究进展

表碛的存在影响了大气与冰川间的能量传输过程,一方面,促进了冰面湖(塘)、冰崖的发育;另一方面,改变了冰川的消融过程和水文模式。利用表碛各项属性和物理参数模型化气候-表碛-冰川间的相互作用和反馈过程能够正确认识表碛覆盖型冰川变化的过程和机理,有助于准确估算和预测冰川物质平衡,进而判断冰川未来演变趋势。本文系统总结和对比了识别表碛范围、提取冰川流速以及获取表碛物理参数的各种技术手段,介绍了表碛覆盖影响下冰川消融模型的原理和应用情况,同时还对这些方法或模型的局限性和发展趋势进行了讨论。表碛覆盖型冰川所处山区地形起伏大、地表变化复杂,为遥感方法识别表碛范围和提取冰川流速带来了诸多困难,如现有表碛识别方法仍无法克服固有干扰因素的影响,而流速提取方法需具备较强抗干扰能力,且配对影像时间基线需尽可能短。当前表碛覆盖型冰川相关研究中关键参数、数据存在大量空缺的状况有望在将来得到改善,冰川动力学过程和表碛动态变化的模型描述将更为精细,冰川物质平衡、径流量等指标的评估和预测也将更为真实准确。

中国阿尔泰山冰川变化脆弱性及适应能力影响因素分析

冰川是冰冻圈重要的组成要素,作为我国西部干旱区重要的淡水资源,冰川变化的脆弱性与区域社会经济发展密切相关。本文以中国阿尔泰山为例,基于遥感影像分析了1990—2020年间阿尔泰山冰川变化的特征,构建了阿尔泰山冰川变化脆弱性的评估框架和指标体系,分析得到2000—2020年阿尔泰山冰川变化脆弱性的时空演变格局,并利用障碍度模型深入探析了冰川变化适应能力的影响因素。研究结果表明,在1990—2020年的近30年间,我国阿尔泰山冰川的面积和储量均减小了约20%,且不同县市冰川面积变化率存在较大的差异,青河县冰川面积缩小率最大,达到73%,布尔津县的冰川面积缩小率最小,仅为18%。阿尔泰山冰川变化脆弱性随时间呈先缓慢下降、后加速上升的趋势,区域差异在不断下降。在空间分布上阿尔泰山西北部和东部地区冰川变化脆弱性中等偏高;西南部地区冰川变化脆弱性偏低;中部地区冰川变化脆弱性在全局范围内最低。适应能力的提升能有效降低阿尔泰山地区冰川变化的脆弱性,以2010年为分界点,阿尔泰山冰川变化适应能力在前期依赖于区域经济和水资源状况的提升和改善,在后期适应能力的提升向社会公共收入与投资以及公共服务质量倾斜明显,各县市适应能力提升途径更加多元且均衡。

Sensitivity analysis of glacier systems to climate warming in China

Data of 44 glacier systems in China used in this paper were obtained from Chinese Glacier Inventories and the meteorological data were got from Meteorological Atlas of Plateau of west China. Based on the statistical analysis and functional model simulation results of the 44 glacier systems in China, the glacier systems were divided into extremely-sensitive glacier system, semi-sensitive glacier system, extremely-steady glacier system and semi-steady glacier system in terms of glacier system＇s level of water-energy exchange, rising gradient of the equilibrium line altitudes and retreating rate of area to climate warming, their median size and vertical span distribution, and their runoff characteristics to climate warming. Furthermore the functional model of glacier system to climate warming was applied in this paper to predict the average variation trends of the 4 types of glacier systems, which indicate that different sensitivity types of glacier systems respond to the climate warming differently.

Modelling Chorabari Lake outburst flood, Kedarnath, India

In this study, the Glacier Lake Outburst Flood(GLOF) that occurred over Kedarnath in June 2013 was modeled using integrated observations from the field and Remote Sensing(RS). The lake breach parameters such as area, depth, breach, and height have been estimated from the field observations and Remote Sensing(RS) data. A number of modelling approaches, including Snow Melt Runoff Model(SRM), Modified Single Flow model(MSF), Watershed Management System(WMS), Simplified Dam Breach Model(SMPDBK) and BREACH were used to model the GLOF. Estimations from SRM produced a runoff of about 22.7 m3 during 16–17, June 2013 over Chorabari Lake. Bathymetry data reported that the lake got filled to its maximum capacity(3822.7 m3) due to excess discharge. Hydrograph obtained from the BREACH model revealed a peak discharge of about 1699 m3/s during an intense water flow episode that lasted for 10–15 minutes on 17 th June 2013. Excess discharge from heavy rainfall and snowmelt into the lake increased its hydrostatic pressure and the lake breached cataclysmically.

Impact of climate change on the streamflow in the glacierized Chu River Basin, Central Asia

Catchments dominated by meltwater runoff are sensitive to climate change as changes in precipitation and temperature inevitably affect the characteristics of glaciermelt/snowmelt, hydrologic circle and water resources. This study simulated the impact of climate change on the runoff generation and streamflow of Chu River Basin （CRB）, a glacierized basin in Central Asia using the enhanced Soil and Water Assessment Tool （SWAT）. The model was calibrated and validated using the measured monthly streamflow data from three discharge gauge stations in CRB for the period 1961-1985 and was subsequently driven by downscaled future climate projections of five Global Circulation Models （GCMs） in Coupled Model Inter-comparison Project Phase 5 （CMIP5） under three radiative forcing scenarios （RCP2.6, RCP4.5 and RCP8.5）. In this study, the period 1966-1995 was used as the baseline period, while 2016-2045 and 2066-2095 as the near-future and far-future period, respectively. As projected, the climate would become warmer and drier under all scenarios in the future, and the future climate would be characterized by larger seasonal and annual variations under higher RCP. A general decreasing trend was identi- fied in the average annual runoff in glacier （-26.6% to -1.0%）, snow （-21.4% to ＋1.1%） and streamflow （-27.7% to -6.6%） for most of the future scenario periods. The projected maximum streamflow in each of the two future scenarios occurred one month earlier than that in the baseline period because of the reduced streamflow in summer months. Results of this study are expected to arouse the serious concern about water resource availability in the headwater region of CRB under the continuously warming climate. Changes in simulated hydrologic outputs underscored the significance of lowering the uncertainties in temperature and precipitation projection.

The mass-balance characteristics and sensitivities to climate variables of Laohugou Glacier No.12,western Qilian Mountains,China

Due to global warming, glaciers on the Tibetan Plateau(TP) are experiencing widespread shrinkage; however, the mechanisms controlling glacier variations across the TP are still rather unclear, especially on the northeastern TP. In this study, a physically based, distributed surface-energy and mass-balance model was used to simulate glacier mass balance forced by meteorological data. The model was applied to Laohugou No. 12 Glacier, western Qilian Mountains, China, during2010~2012. The simulated albedo and mass balance were validated and calibrated by in situ measurements. The simulated annual glacier-wide mass balances were-385 mm water equivalent(w.e.) in 2010/2011 and-232 mm w.e. in 2011/2012,respectively. The mean equilibrium-line altitude(ELA) was 5,015 m a.s.l., during 2010~2012, which ascended by 215 m compared to that in the 1970 s. The mean accumulation area ratio(AAR) was 39% during the two years. Climatic-sensitivity experiments indicated that the change of glacier mass balance resulting from a 1.5 °C increase in air temperature could be offset by a 30% increase in annual precipitation. The glacier mass balance varied linearly with precipitation, at a rate of130 mm w.e. per 10% change in total precipitation.

The Glacier Area Changes in the Qangtang Plateau Based on the Multi-temporal Grid Method and its Sensitivity to Climate Change

Glacier area changes in the Qangtang Plateau are analyzed during 1970-2000 using air photos,relevant photogrammetric maps and satellite images based on the multi-temporal grid method.The results indicate that the melting of glaciers accelerated,only a few of glaciers in an advancing state during 1970-2000 in the whole Qangtang Plateau.However,the glaciers seemed still more stable in the study area than in most areas of western China.We estimate that glacier retreat was likely due to air temperature warming during 1970-2000 in the Qangtang Plateau.Furthermore,the functional model of glacier system is applied to study climate sensitivity of glacier area changes,which indicates that glacier lifespan mainly depends on the heating rate,secondly the precipitation,and precipitation increasing can slow down glacier retreat and make glacier lifespan prolonged.

Assessment of Water Provenances in Koxkar Glacier Region at the South Slope of Mt. Tianshan,China

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.

Inventory and Geometrical Changes in Small Glaciers Covering Three Northern Patagonian Summits Using Remote Sensing and GIS Techniques

In the last few decades, a large quantity of research has been performed to elucidate the current behavior of glaciers in southern Chile, especially with respect to the volumetric changes in the outlets of the Northern and Southern Patagonian Icefields (NPI and SPI, respectively). Calculations have shown a generalized thinning and withdrawal, which greatly contributes to the increase in sea level attributed to the ice melt from non-polar glaciers. However, these icefields are surrounded by many small icecaps, which have yet to be studied in detail. A precise estimation of the volume of ice located in these mountain chains could provide new information with respect to this area's exact contribution to the increase in sea level. Thus, this study presents an inventory of relatively small Northern Patagonian glaciers in the surrounding of the three summits: Mount Queulat, and the Macá and Hudson volcanoes. The study used remote sensing techniques in a GIS environment to determine the margins, surface areas, thickness changes and hypsometry for the glaciated zones. Landsat images from different dates were analyzed using standard band ratio and screen delineation techniques. Additionally, digital elevation models from different dates were compared using map algebra, calculating thickness changes. Based on the results, we propose that there are important volumetric changes in the glaciers studied, which could be explained by precipitation trends in a general context, and an influence of the glaciers' sizes in some local response. Therefore, we suggest the exact contribution of the Patagonia to the increase in sea level corresponds to a regional pattern rather than just the behavior of a single ice field.

Response of Xiao Dongkemadi Glacier in the central Tibetan Plateau to the current climate change and future scenarios by 2050

The Tibetan Plateau(TP) holds ten thousands of alpine glaciers in mid-latitude.They have shrunk with an accelerating retreat rate recently.We applied a distributed temperature-index massbalance model developed by Regine Hock,and coupled with a volume-area scaling method to Xiao Dongkemadi Glacier(XDG) in the central TP,to assess its response to climate change.The result shows the simulated mass balance is in a good agreement with observations(R^2=0.75,p<0.001) during the period of 1989-2012.The simulated mean annual mass balance(-213 mm w.e.) is close to the observation(-233 mm w.e.),indicating the model can be used to estimate the glacier variation in the future.Then the model was forced by the output of Reg CM4 under the climate scenarios RCP4.5 and RCP8.5 from 2013 to 2050.The simulated terminus elevation of the glacier will rise from 5454 m a.s.l.in 2013 to 5533 m a.s.l.(RCP4.5) and 5543 m a.s.l.(RCP8.5) in 2050.XDG will lose its volume with an increasing rate of 600-700 m3 a-1 during the period of 1989-2050,indicating the melting water will enhance the riverrunoff.But for the long term,the contribution to the river runoff will decrease for the shrinkage of glacier scale.

Study on mass balance and sensitivity to climate change in summer on the Qiyi Glacier,Qilian Mountains

Based on the glacier mass balance and meteorological data of air temperature and precipitation on the Qiyi Glacier from June 30 to September 5, 2010, we used a degree-day mass balance model to simulate the change of mass balance during this period. Our results indicate that the current value of the mass balance is -856.2 mm w.e. Subjected to the strong influences of air temperature and precipitation, the mass balance process can be divided into three stages： accumulating exiguously ~ melting intensively melting exiguously. The variation trends of the mass balance according to the degree-day mass balance model and the observed values are similar and wholly reflect the spatial distribution characteristics of the glacier mass balance, which increases with the increase of altitude. Our experiment on climate sensitivity of the mass balance showed that mass balance was very sensitive to the change of temperature; air temperature is the key factor which influences mass balance; and a slight increase in precipitation will have a negligible effect on mass balance when the air temperature increases continuously.

The impacts of climate change on hydrology in a typical glacier region A case study in Hailuo Creek watershed of Mt.Gongga in China

The glaciers of the Hengduan Mountains play an important role in the hydrology processes of this region. In this study, the HBV Light model, which relies on a degree-day model to simulate glacier melting, was employed to simulate both glacier runoffand total runoff. The daily temperature and precipitation at the Hailuo Creek No. 1 Glacier from 1952 to 2009 were obtained from daily meteorological observed data at the glacier and from six national meteorological stations near the Hailuo Creek Basin. The daily air temperature, precipitation, runoff depth, and monthly potential evaporation in 1995, 1996, and 2002 were used to obtain a set of optimal parameters, and the annual total runoff and glacier runoff of the Hailuo Creek Glacier （1952--2009） were calculated using the HBV Light model. Results showed the average annual runoff in the Hailuo Creek Basin was 2,114 mm from 1952 to 2009, of which glacial melting accounted for about 1,078 mm. The river runoff in the Hailuo Creek catchment increased as a result of increased glacier runoff. Glacier runoff accounted for 51.1% of the Hailuo Creek stream flow in 1994 and increased to 72.6% in 2006. About 95% of the increased stream flow derived from the increased ~lacier runoff.

Projection of future streamflow of the Hunza River Basin,Karakoram Range(Pakistan)using HBV hydrological model

Hydrologiska Byrans Vattenbalansavdeling(HBV) Light model was used to evaluate the performance of the model in response to climate change in the snowy and glaciated catchment area of Hunza River Basin. The study aimed to understand the temporal variation of streamflow of Hunza River and its contribution to Indus River System(IRS). HBV model performed fairly well both during calibration(R2=0.87, Reff=0.85, PBIAS=-0.36) and validation(R2=0.86, Reff=0.83, PBIAS=-13.58) periods on daily time scale in the Hunza River Basin. Model performed better on monthly time scale with slightly underestimated low flows period during bothcalibration(R2=0.94, Reff=0.88, PBIAS=0.47) and validation(R2=0.92, Reff=0.85, PBIAS=15.83) periods. Simulated streamflow analysis from 1995-2010 unveiled that the average percentage contribution of snow, rain and glacier melt to the streamflow of Hunza River is about 16.5%, 19.4% and 64% respectively. In addition, the HBV-Light model performance was also evaluated for prediction of future streamflow in the Hunza River using future projected data of three General Circulation Model(GCMs) i.e. BCC-CSM1.1, CanESM2, and MIROCESM under RCP2.6, 4.5 and 8.5 and predictions were made over three time periods, 2010-2039, 2040-2069 and 2070-2099, using 1980-2010 as the control period. Overall projected climate results reveal that temperature and precipitation are the most sensitiveparameters to the streamflow of Hunza River. MIROC-ESM predicted the highest increase in the future streamflow of the Hunza River due to increase in temperature and precipitation under RCP4.5 and 8.5 scenarios from 2010-2099 while predicted slight increase in the streamflow under RCP2.6 during the start and end of the 21 th century. However, BCCCSM1.1 predicted decrease in the streamflow under RCP8.5 due to decrease in temperature and precipitation from 2010-2099. However, Can ESM2 predicted 22%-88% increase in the streamflow under RCP4.5 from 2010-2099. The results of this study could be useful for decision making and effective future strategic plans for water management and their sustainability in the region.

1980—2019年藏东南帕隆藏布流域冰川物质平衡模拟

帕隆藏布流域位于中国海洋性冰川发育最为集中的藏东南地区,近年来随着全球气候变暖,帕隆藏布流域冰川亏损显著。利用全球开放冰川模型(OGGM)模拟了1980—2019年藏东南地区帕隆藏布流域1554条冰川物质平衡,发现1980—2019年帕隆藏布流域全域冰川物质平衡呈现不断亏损的状态,为-0.41 m w.e.·a^(-1),在2000—2019年物质平衡亏损更为严重,达到-0.56 m w.e.·a^(-1)。从空间分布上来看,流域东南部和流域西北部是冰川亏损最为严重的区域,流域中部和西部冰川亏损相比较少。温度的升高和降水的轻微减少是冰川物质亏损的主要原因。通过气温和降水的敏感性分析,气温上升1℃,流域71.75%的冰川物质平衡变化在-1000~-500 mm w.e.·a^(-1);降水减少20%,62.81%的冰川物质平衡变化在-450~-300 mm w.e.·a^(-1),相较于降水,冰川对气温变化更为敏感。通过分析国家气象站及再分析数据,发现1980—2019年气象站气温上升均超过1.5℃,波密站2000—2019年总降水相较于前20年,减少了10%,流域降水整体呈现减少的趋势,气温的持续升高和降水的轻微减少导致帕隆藏布流域冰川处于持续亏损之中。