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Hydro-climatic Characteristics of Yarlung Zangbo River Basin since the Last Glacial Maximum

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Advances in Atmospheric Sciences 2022年第3期39卷 415-426页

作者： Shuang LIU kaiheng hu Weiming LIU Paul A.CARLING Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China Geography&Environment University of SouthamptonHighfieldSouthamptonSO171BJUK

Global climate changes significantly impact the water condition of big rivers in glacierized high mountains. However,there is a lack of studies on hydrological changes within river basins caused by climate changes over a geological timescale due to the impossibility of direct observations. In this study, we examine the hydro-climatic variation of the Yarlung Zangbo River Basin in the Tibet Plateau since the Last Glacial Maximum(LGM) by combining δ18 O proxy records in Indian and Omani caves with the simulated Indian summer monsoon, surface temperature, precipitation, evapotranspiration and runoff via the Community Climate System Model and the reconstructed glacier coverage via the Parallel Ice Sheet Model. The mean river runoff was kept at a low level of 145 billion cubic meters per year until an abrupt increase at a rate of 8.7 million cubic meters per year in the B?lling-Aller?d interval(BA). The annual runoff reached a maximum of 250 billion cubic meters in the early Holocene and then reduced to the current value of 180 billion cubic meters at a rate of 6.4 million cubic meters per year. The low runoff in the LGM and Heinrich Stadial 1(HS1) is likely attributed to such a small contribution of precipitation to runoff and the large glacier cover. The percentage of precipitation to runoff was only 20%during the LGM and HS1. Comparison of glacier area among different periods indicates that the fastest deglaciation occurred during the late HS1, when nearly 60% of glacier area disappeared in the middle reach, 50% in the upper reach,and 30% in the lower reach. The rapid deglaciation and increasing runoff between the late HS1 and BA may have accelerated widespread ice-dam breaches and led to extreme outburst flood events. Combining local geological proxy records and regional simulations could be a useful approach for the study of paleo-hydrologic variations in big river basins.

关键词： Yarlung Zangbo River Basin Indian summer monsoon glacier change runoff variability since the LGM

Evaluation of rainfall threshold models for debris flow initiation in the Jiangjia Gully,Yunnan Province,China

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Journal of Mountain Science 2024年第6期21卷 1799-1813页

作者： YANG Hongjuan ZHANG Shaojie hu kaiheng WEI Fangqiang LIU Yanhui State Key Laboratory of Mountain Hazards and Engineering Resilience Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610299China Chongqing Institute of Green and Intelligent Technology Chinese Academy of SciencesChongqing 400714China Chongqing School University of Chinese Academy of SciencesChongqing 400714China China Institute of Geo-Environment Monitoring Beijing 100081China

Systematically determining the discriminatory power of various rainfall properties and their combinations in identifying debris flow occurrence is crucial for early warning *** this study,we evaluated the discriminatory power of different univariate and multivariate rainfall threshold models in identifying triggering conditions of debris flow in the Jiangjia Gully,Yunnan Province,*** univariate models used single rainfall properties as indicators,including total rainfall(R_(tot)),rainfall duration(D),mean intensity(I_(mean)),absolute energy(Eabs),storm kinetic energy(E_(s)),antecedent rainfall(R_(a)),and maximum rainfall intensity over various durations(I_(max_dur)).The evaluation reveals that the I_(max_dur)and Eabs models have the best performance,followed by the E_(s),R_(tot),and I_(mean)models,while the D and R_(a)models have poor ***,the I_(max_dur)model has the highest performance metrics at a 40-min *** used logistic regression to combine at least two rainfall properties to establish multivariate threshold *** results show that adding D or R_(a)to the models dominated by Eabs,E_(s),R_(tot),or I_(mean)generally improve their performances,specifically when D is combined with I_(mean)or when R_(a)is combined with Eabs or E_(s).Including R_(a)in the I_(max_dur)model,it performs better than the univariate I_(max_dur)model.A power-law relationship between I_(max_dur)and R_(a)or between Eabs and R_(a)has better performance than the traditional I_(mean)–D model,while the performance of the E_(s)–R_(a)model is *** evaluation reemphasizes the important role of the maximum intensity over short durations in debris flow *** also highlights the importance of systematically investigating the role of R_(a)in establishing rainfall thresholds for triggering debris *** the regional variations in rainfall patterns worldwide,it is necessary to evaluate the findings of this study across diverse watersheds.

关键词： Rainfall threshold Logistic regression Maximum rainfall intensity Absolute energy Antecedent rainfall

Seasonal constraint of dynamic water temperature on riverine dissolved inorganic nitrogen transport in land surface modeling

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Atmospheric and Oceanic Science Letters 2024年第4期17卷 35-40页

作者： Shuang Liu kaiheng hu Zhenghui Xie Yan Wang State Key Laboratory of Mountain Hazards and Engineering Safety Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengduChina State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina The National Key Laboratory of Water Disaster Prevention Nanjing Hydraulic Research InstituteNanjingChina

水体温度变化对河流可溶性无机氮(DIN)输送有着强烈控制作用.然而,在全球尺度上河流DIN输送量对水温度变化的响应尚不清楚.因此,本文基于陆面过程模式,耦合河流水温估算和DIN传输方案,设定有,无动态水温情景,对比研究陆面模拟中水温变... 详细信息

水体温度变化对河流可溶性无机氮(DIN)输送有着强烈控制作用.然而,在全球尺度上河流DIN输送量对水温度变化的响应尚不清楚.因此,本文基于陆面过程模式,耦合河流水温估算和DIN传输方案,设定有,无动态水温情景,对比研究陆面模拟中水温变化对河流DIN通量变化的影响.结果表明:在考虑水温动态变化后,在30°N和30°S之间, DIN通量年振幅减小5%–25%.在中国东部地区,水温动态变化使河流DIN通量在夏季减少1%–3%,在冬季增加1%–5%,对DIN通量具有明显的季节性约束作用,表明动态水温的表达在河流DIN输送模拟中的重要性.

关键词：陆面模拟河流氮输送水温变化季节变化全球尺度

Numerical Investigation on the Initiation Mechanism of Debris-Flow under Rainfall

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Journal of Mountain Science 2011年第4期8卷 619-628页

作者： LU Xiaobing YE Tianli CUI Peng hu kaiheng CHEN Xiaoqing Institute of Mechanics Chinese Academy of Science Beijing 100084 China Institute of Mountain Hazards and Environment Chinese Academy of Science Chengdu 610041 China

Rainfall is an important factor to trigger the debris *** simulation on the responses of slopes and the initiation of debris flow under rainfall was processed by using the software FLAC2D based on the soil parameters in Weijia Gully,Beichuan County,Sichuan Province,*** effects of the slope angle,rainfall intensity,soil parameters on the developments of the stress and pore pressure and deformation of the slope were *** indicates that large displacements of the slope are mainly located near the slope *** the increase of the rainfall intensity the stability of the slope decreases and so the debris-flow is easy to occur.

关键词： Debris-flow Initiation mechanism Rainfall Numerical simulation

Model and Method of Debris Flow Risk Zoning Based on Momentum Analysis

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Wuhan University Journal of Natural Sciences 2006年第4期11卷 835-839页

作者： WEI Fangqiang ZHANG Yu hu kaiheng GAO Kechang Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 SichuanChina Dongchuan Station of Debris Flow Observation and Research Chinese Academy of Sciences Dongchuan 654112Yunan China

A model of debris flow risk zoning is carried out with momentum analysis of debris flow. This model zones the debris flow inundation fan with density and velocity calculated by numerical simulation. The risk classification standard is determined according to the ultimate bearing capacities of different structures under impacting. And the ultimate bearing capacities are tested by impact failure experiment of destruction. Two structures typical in Chinese mountain towns, reinforced concrete frame construction and brickwork with concrete, are chosen in the experiment. The model makes debris flow risk zoning quantitative and the results comparable widely. The results differ much from that of other methods especially in the identification of medium and low risk zones.

关键词： debris flow risk zoning momentum ultimate bearing capacity

Evidence of ancient rock-ice avalanches along the China-Bhutan Chomolhari Range,and their implications for demise of the summit

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Journal of Mountain Science 2024年第9期21卷 2876-2890页

作者： hu kaiheng ZHANG Qiyuan LI Pu ZHANG Xiaopeng LIU Shuang LI Hao Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610299China University of Chinese Academy of Sciences Beijing 100149China

Large-scale rock-ice avalanches resulting from the interaction of tectonics and climate are characterized with high mobility,huge volumes of sediment,and rapid denudation,being a major agent of landscape evolution in high altitude mountainous ***,the extreme glaciated slope failures often transform into extraordinarily large and mobile debris flows,resulting in disastrous consequences such as sedimentation and *** to a dearth of on-site observation data and experimental data collection,our comprehension of the geomorphic and kinematic characteristics of rock-ice avalanches remains *** we report a cluster of ancient rock-ice avalanches spreading along the Chomolhari range of the China-Bhutan *** integrating remote sensing image interpretation with detailed field investigations,we demonstrate the geomorphic and sedimentary characteristics of four events among the *** estimated volumes of the four are 23.73 Mm³,39.69 Mm³,38.43 Mm³,and 38.25 Mm³,*** presence of pre-existing moraines or alluvial fans constrained their movement,resulting in deposition features such as marginal digitated lobes at higher elevations and large depressed areas in the *** the Savage-hutter theory,we calculate the basal friction angle and travel angle of these ancient rock-ice avalanches that are both less than 10°,affirming the similarity of these avalanches in the study area to those occurring in other *** study significantly contributes to understanding the geomorphic and kinematic characteristics of rock-ice avalanches in high-altitude mountainous regions,providing valuable insights into their response to the disproportionate growth of Himalayan peaks.

关键词： Rock-ice avalanche Himalayas Southern Yadong-Gulu rift Vertical slip-rate Landscape evolution

A depth-averaged two-phase model for debris flows over fixed beds

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International Journal of Sediment Research 2018年第4期33卷 462-477页

作者： Ji Li Zhixian Cao kaiheng hu Gareth Pender Qingquan Liu State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Institute of Mountain Hazards and Environment Chinese Academy of Sciences Institute for Infrastructure and Environment.Heriot-Watt University Edinburgh Campus Department of Mechanics Beijing Institute of Technology

A depth-averaged two-phase model is proposed for debris flows over fixed beds, explicitly incorporating interphase and particle-particle interactions, fluid and solid fluctuations and multi grain sizes. A firstorder model based on the kinetic theory of granular flows is employed to determine the stresses due to solid fluctuations, while the turbulent kinetic energy-dissipation rate model is used to determine the stresses from fluid fluctuations. A well-balanced numerical algorithm is applied to solve the governing equations. The present model is benchmarked against USGS experimental debris flows over fixed *** the stresses due to fluid and solid fluctuations and properly estimating the bed shear stresses are shown to be crucial for reproducing the debris flows. Longitudinal particle segregation is resolved, demonstrating coarser sediments around the fronts and finer grains trailing the head. Based on extended modeling exercises, debris flow efficiency is shown to increase with initial volume, which is underpinned by observed datasets.

关键词： Debris flow Two-phase model Depth-averaged model Fluctuation kinetic energy Multi grain sizes

Experimental Study on the Viscoelastic Behaviors of Debris Flow Slurry

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Journal of Mountain Science 2012年第4期9卷 501-510页

作者： WANG Yuyi TAN Rongzhi hu kaiheng CHEN Feiyue YANG Hongjuan ZHANGJinshan LV Juan Key Laboratory of Mountain Hazards and Earth Surface Process Dongchuan Debris Flow Observation and Research Station Chinese Academy of Sciences Chengdu 610041 China Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China Shanghai Representative Office Anton Paar GmbH Shanghai 200040 China

The rheological properties of most liquid in nature are between liquids and solids, including both elastic changes and viscosity changes, that is socalled ＂viscoelastic＂. Dynamic oscillatory test was used to quantitatively study the distinct viscoelastic behaviors of debris flow slurry in the shear stress conditions for the first time in this study. The debris flow slurry samples were from Jiangjiagou Ravine, Yunnan Province, China. The experimental results were found that at the low and middle stages of shearing, when the angular velocity 09〈72.46 s-1, the loss modulus （G was greater than the storage modulus （G3, i.e. G＂〉G＇. At the late stage of shearing, when the angular velocity co-72.46 s-x, the storage modulus was greater than or equal to the loss G = G, tan -〈 1 （where phase-shift modulus, i.e. ＇〉＂ angle 5=G＂,/G3, and the debris flow slurry was in a gel state. Therefore, the progress of this experimental study further reveals the mechanism of hyperconcentrated debris flows with a high velocity on low-gradient ravines.

关键词： Loss modulus (G" Storage modulus (G' Viscoelastic behaviors Gel state

Quantifying the impact of earthquakes and geological factors on spatial heterogeneity of debris-flow prone areas:A case study in the Hengduan Mountains

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Journal of Mountain Science 2024年第5期21卷 1522-1533页

作者： hu Xudong SHEN Yitong hu kaiheng XU Wennian LIU Daxiang HE Songtang GAO Jiazhen WEI Li LIU Shuang hubei Provincial Engineering Research Center of Slope Habitat Construction Technique Using Cement-based Materials(China Three Gorges University) Yichang 443002China hubei Key Laboratory of Disaster Prevention and Mitigation(China Three Gorges University) Yichang 443002China College of Civil Engineering and Architecture China Three Gorges UniversityYichang 443002China Shanghai Investigation Design&Research Institute Co.Ltd.Shanghai 200335China Key Laboratory of Mountain Hazards and Earth Surface Processes Chinese Academy of SciencesChengdu 610041China Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China Wuhan Polytechnic Wuhan 430074China

Understanding the spatial heterogeneity of debris-flow-prone areas holds significant implications for regional risk management, particularly in seismically active regions with geological faults. Despite the significance of this knowledge, a comprehensive quantification of the influence of regional topographical and geological factors on the spatial heterogeneity of debris-flow-prone areas has been lacking. This study selected the Hengduan Mountains, an earthquake-prone region characterized by diverse surface conditions and complex landforms, as a representative study area. An improved units zoning and objective factors identification methodology was employed in earthquake and fault analysis to assess the impact of seismic activity and geological factors on spatial heterogeneity of debrisflow prone areas. Results showed that the application of GIS technology with hydrodynamic intensity and geographical units analysis can effectively analyze debris-flow prone areas. Meanwhile, earthquake and fault zones obviously increase the density of debrisflow prone catchments and make them unevenly distributed. The number of debris-flow prone areas shows a nonlinear variation with the gradual increase of geomorphic factor value. Specifically, the area with 1000 m-2500 m elevation difference, 25°-30° average slope, and 0.13-0.15 land use index is the most favorable conditions for debris-flow occurrence;The average annual rainfall from 600 to 1150 mm and landslides gradient from 16° to 35° are the main causal factors to trigger debris flow. Our study sheds light on the quantification of spatial heterogeneity in debris flow-prone areas in earthquake-prone regions, which can offer crucial support for post-debris flow risk management strategies.

关键词： debris-flow prone areas causal factors GIS-based method spatial heterogeneity Hengduan Mountains