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Temperature and Precipitation Variations at Two Meteorological Stations on Eastern Slope of Gongga mountain,SW China in the Past Two Decades

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Journal of mountain Science 2013年第3期10卷 370-377页

作者： WU Yan-hong LI Wei ZHOU Jun CAO Yang Key Laboratory of mountain Surface Processes and Ecological Regulation Chengdu Institute of Mountain Hazards and EnvironmentChinese Academy of Sciences

Gongga mountain, locates on the eastern edge of Tibetan Plateau of China, is the highest mountain in China except summits in Tibet. Only limited meteorological data on Gongga mountain have been published so far. Here we present the meteorological records from two stations, Moxi Station （at 1,621.7 m above sea level （a.s.1.）, 1992- 2010） and Hailuogou Station （at 2,947.8 m a.s.l., 1988-2010）, on the eastern slope of Gongga mountain. In the past two decades, the annual precipitation decreased while the annual mean temperature increased at Hailuogou Station. Both precipitation and temperature increased at Moxi Station. The precipitation variation on the eastern slope of Gongga mountain is influenced by both East Asian Monsoon and Indian Monsoon, so that the precipitation concentrated between May and October. The temperature variation on the eastern slope of Gongga mountain in the past two decades showed similar trends as that of the northern hemispheric and global. In the past two decades, the temperature increased o.35℃ and o.3℃/decade at Hailuogou Station and Moxi Station respectively, which was higher than the increase extents of northern hemispheric and global temperature. The most intense warming occurred at the first decade of 21St century. The winter temperature increased more at Hailuogou Station than at Moxi Station. A remarkable increase of temperature in March was observed with only a little precipitation at both high and low altitude stations.

关键词： Temperature Precipitation Variation Global change Gongga mountain

Study on the Rainfall and Aftershock Threshold for Debris Flow of Post-earthquake

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Journal of mountain Science 2011年第5期8卷 750-756页

作者： HE Siming LI Dexin WU Yong LUO Yu Key laboratory of mountain hazards and Earth Surface Process Chinese Academy of Science Chengdu 610041 China institute of mountain hazards and Environment Chinese Academy of Science Chengdu 610041 China

Due to the special condition of provenance and disaster environment after "5·12" Earthquake, the probability and conditions of the occurrence of gully debris flow change greatly after the event, which make it difficult to prevent disaster effectively. In this study the hydrological model of ground water table in loose sediment is established. According to infinite slope theory, the safety factor of deposits is defined as the ratio of resistance force to driving force. The starting condition of post-earthquake gully debris flow is clearly studied by analyzing the effects of rainfall intensity, seismic strength, slope gradient and mechanical properties on the balance of accumulation body. Then the formulas of rainfall and aftershock threshold for starting of gully debris flow are proposed, and an example is given to illustrate the effect of rainfall, aftershocks and their coupling action on a debris flow. The result shows the critical rainfall intensity decreases as the lateral seismic acceleration and channel gradient increases, while the critical intensity linearly increases as the friction angle increases.

关键词： Earthquake Hydrological model Debris flow Rainfall threshold

Artificial Neural Network-based prediction of glacial debris flows in the ParlungZangbo Basin, southeastern Tibetan Plateau,China

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Journal of mountain Science 2021年第1期18卷 51-67页

作者： TANG Wang DING Hai-tao CHEN Ning-sheng MA Shang-Chang LIU Li-hong WU Kang-lin TIAN Shu-feng Chengdu University of Information Technology Chengdu 610225China Key Laboratory of mountain hazards and Surface Process Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China

Accurate prediction on geological hazards can prevent disaster events in advance and greatly reduce property losses and life *** debris flows are the most serious hazards in southeastern Tibet in China due to their complexity in formation mechanism and the difficulty in *** collected from 102 glacier debris flow events from 31 gullies since 1970 and regional meteorological data from 1970 to 2019 in ParlungZangbo River Basin in southeastern Tibet were used for Artificial Neural Network(ANN)-based prediction of glacial debris *** formation mechanism of glacial debris flows in the ParlungZangbo Basin was systematically analyzed,and the calculations involving the meteorological data and disaster events were conducted by using the statistical methods and two layers fully connected neural *** occurrence probabilities and scales of glacial debris flows(small,medium,and large)were predicted,and promising results have been *** the proposed model calculations,a prediction accuracy of 78.33%was achieved for the scale of glacial debris flows in the study *** prediction accuracy for both large-and medium-scale debris flows are higher than that for small-scale debris *** debris flow scale and the probability of occurrence increase with increasing rainfall and *** addition,the K-fold cross-validation method was used to verify the reliability of the *** average accuracy of the model calculated under this method is about 93.3%,which validates the proposed *** have proved that the combination of ANN and disaster events can provide sound prediction on geological hazards under complex conditions.

关键词： Two layers neural networks Glacial debris flow Disaster events K-fold cross-validation Rainfall Temperature

Failure Mechanisms of Post-Earthquake Bedrock Landslides in Response to Rainfall Infiltration

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Journal of mountain Science 2011年第1期8卷 96-102页

作者： WU Yong HE Siming LUO Yu LI Xinpo Key laboratory of mountain hazards and Earth Surface Process Chinese Aeademy of Sciences Chengdu 610041 China institute of mountain hazards and Environment Chinese Academy of Sciences Chengdu 610041 China

Among the triggering factors of postearthquake bedrock landslides, rainfall plays an important role. However, with slope variation, the mechanism of its effects on the failure of rock landslides is not dear. Here, from the viewpoint of fracture mechanics, and based on post-earthquake conditions, the mechanisms of crack propagation, water infiltration and development of the sliding surface were investigated. Then, according to the upper boundary theorem, the effects of water infiltrated into fractures on the stability of rock slopes were analyzed quantitatively. Finally, an example is presented to verify the theory. The results show that the propagation and coalescence of cracks and the lubrication of incipient sliding surfaces are the main causes of the failure of post-earthquake rock landslides in response to rainfall.

关键词： Post-earthquake Fracture infiltration Fracture mechanics Propagation and coalescence Upper boundary theorem Energy theory Rock landslide

Trends and drivers of soil multifunctionality along elevation gradients in the Altun Shan drylands of China

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Journal of mountain Science 2023年第11期20卷 3203-3214页

作者： ZHANG Shi-hang CHEN Yu-sen LU Yong-xing GUO Hao GUO Xing ZHOU Xiao-bing ZHANG Yuan-ming State Key Laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy ofSciencesUrumqi 830011China Key Laboratory of mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards andEnvironmentChinese Academy of Sciences610041 ChengduChina University of Chinese Academy of Sciences Beijing 100049China

This study was conducted to analyze the variation of soil multifunctionality(SMF)along elevation and the driving factors in the Altun *** samples(0–10 cm)were collected from 15 sites(H01 to H15)at every 200 m elevation interval,covering a total range from 900 m to 3500 m above mean sea *** investigated climate factors(mean annual temperature,MAT;mean annual precipitation,MAP),soil environment(soil water content,electrical conductance,and pH),vegetation factors,and elevation to determine which of them are the main driving factors of the spatial variability of SMF in the Altun *** explored the best-fit model of SMF along the changes in elevation using a structural equation model,performed variance partitioning analysis(VPA)on SMF with the“varpart”function to explain the relative contribution of various environmental factors to SMF changes,and used a random forest model for relative importance *** results showed that SMF in the Altun Shan significantly increased with elevation in a linear *** main driver of changes in SMF was found to be *** the rise in elevation did not have a significant direct effect on changes in SMF,it could indirectly affect SMF by significantly influencing MAP,p H,MAT,and normalized difference vegetation index(NDVI).When considering climate,soil environment,and vegetation factors together,they explained 76%of the variation in *** largest contribution to the variation in SMF was attributed to the independent effect of climate(0.31)and its interactive effect with soil(0.30).The relative importance of MAP on SMF changes was found to be the *** is indicated that changes in SMF are caused by the combined effect of multiple environmental *** findings are essential for understanding the spatial variability and drivers of SMF in dryland mountain ecosystems,especially concerning the function of mountain ecosystems in the context of global climatic changes.

关键词： Climate change mountain ecosystems Structural equation model Aridisols

Debris Flow Warning Threshold Based on Antecedent Rainfall:a Case Study in Jiangjia Ravine,Yunnan,China

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Journal of mountain Science 2013年第2期10卷 305-314页

作者： GUO Xiao-jun CUI Peng LI Yong Key Laboratory of mountain hazards and Earth Surface Process and /institute of mountain hazards and Environment Chinese Academy of Sciences Asian Network on Debris Flow Graduate University of Chinese Academy of Sciences

Debris flows in Jiangjia Ravine in Yunnan province, China are not only triggered by intense storms but also by short-duration and low-intensity rainfalls. This reflects the significance of antecedent rainfall. This paper tries to find the debris flow- triggering threshold by considering antecedent rainfall through a case study in Jiangjia Ravine. From 23 debris flow events, the I-D （Intensity-Duration） threshold was found, which is very dose to the line of 95th percentile regression line of rainfall events, representing that 95% of rainfalls can potentially induce debris flows and reflects the limitation of I-D threshold application in this area. Taking into account the effect of antecedent rainfall, the debris flowtriggering threshold for rainfall quantity and intensity is statistically and empirically derived. The relationships can be used in debris flow warning system as key thresholds. Coupling with the rainfall characteristics in this area, new thresholds are proposed as triggering and warning thresholds.

关键词： I-D threshold debris flow warningsystem antecedent rainfall Jiangjia Ravine

Modeling of breaching parameters for debris flow dams

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Journal of mountain Science 2023年第10期20卷 2835-2851页

作者： RUAN He-chun CHEN Hua-yong CHEN Xiao-qing ZHAO Wan-yu CHEN Jian-gang WANG Tao JIANG Yao Wang Xi-an Li Xiang-ning LI Xiao YU Yun-han Key Laboratory of mountain hazards and Surface Processes Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100000China

The debris flow dam is a common type of barrier dams,which shows significant differences from other types of barrier dam such as landslide dam,moraine dam in their formation processes,dam body shapes,and internal *** basic breaching parameters such as flood peak discharge are vital indicators of risk *** this study,we elucidated the failure process of the debris flow dam through the flume experiment,and built the calculation equation of the breaching parameters by selecting critical *** result shows that the overtopping failure process of the debris flow dam is capable of forming significantly retrogressive scarps,and the failure process experiences three stages,the formation of the retrogressive scarp,the erosion of the retrogressive scarp,and the decline of the retrogressive *** factors used for establishing the calculation equations for peak discharge(Qp),final width(Wb)of the breach,and duration(T)of the debris flow dam failure are dam height(h),reservoir capacity(V),the fine grain content(P0.075)of the soil,the nonuniformity coefficient(Cu)of the soil,and the upper limit grain size(D90)of the soil,*** the three equations,the correlation coefficients between Qp,Wb,T and the five factors were 0.86,0.70,0.63,*** equations still need to be modified and verified in actual cases.

关键词： Debris flow dams Overtopping failure Breaching g parameters Peak discharge Flume experiment

Landslide susceptibility assessment of the region affected by the 25 April 2015 Gorkha earthquake of Nepal

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Journal of mountain Science 2016年第11期13卷 1941-1957页

作者： Amar Deep Regmi Megh Raj Dhital ZHANG Jian-qiang SU Li-jun CHEN Xiao-qing Key Laboratory of mountain hazards and Earth Surface Process Institute of Mountain Hazards and EnvironmentCASChengdu 610041China Central Department of Geology Tribhuvan UniversityKirtipur 44613Nepal

Nepal was hit by a 7.8 magnitude earthquake on 25^(th) April,*** main shock and many large aftershocks generated a large number of coseismic landslips in central *** have developed a landslide susceptibility map of the affected region based on the coseismic landslides collected from remotely sensed data and fieldwork,using bivariate statistical model with different landslide causative *** the investigation,it is observed that most of the coseismic landslides are independent of previous *** of 3,716 mapped landslides,we used 80% of them to develop a susceptibility map and the remaining 20% were taken for validating the model.A total of 11 different landslide-influencing parameters were *** include slope gradient,slope aspect,plan curvature,elevation,relative relief,Peak Ground Acceleration(PGA),distance from epicenters of the mainshock and major aftershocks,lithology,distance of the landslide from the fault,fold,and drainage *** success rate of 87.66% and the prediction rate of86.87% indicate that the model is in good agreement between the developed susceptibility map and theexisting landslides ***,lithology,slope angle and elevation have played a major role in triggering the coseismic mass *** susceptibility map can be used for relocating the people in the affected regions as well as for future land development.

关键词： Earthquake Himalaya Coseismic landslide Susceptibility bivariate statistical model Nepal

mountain hazards in the Tibetan Plateau: research status and prospects

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National Science Review 2015年第4期2卷 397-399页

作者： Peng Cui Yang Jia Key Laboratory of mountain hazards and Surface Process Institute of Mountain Hazards and Environment Chinese Academy of Sciences University of Chinese Academy of Sciences

The intense tectonic activities and complex geomorphology have made the Tibetan Plateau the highly potential area of mountain hazards,including glacial lake outburst,torrential loods,debris lows,landslides,and avalanc... 详细信息

关键词： mountain hazards in the Tibetan Plateau research status and prospects high