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Impacts of spatially inconsistent permafrost degradation on streamflow in the Lena River Basin

Science China Technological Sciences 2024年第11期67卷 3559-3570页

作者： XUE ZeHuan WANG YiChu ZHAO Yi LI DongDeng BORTHWICK Alistair George Liam The Key Laboratory of Water and Sediment Sciences Ministry of EducationCollege of Environmental Sciences and EngineeringPeking University College of Water Sciences Beijing Normal University State Key Laboratory of hydraulics and Mountain River Engineering Sichuan University State Environmental Protection Key Laboratory of All Materials Fluxes in River Ecosystems Peking University School of Engineering The University of Edinburgh School of Engineering Computing and MathematicsUniversity of Plymouth

Although permafrost degradation contributes significantly to hydrological change in cold regions, gaps remain in our understanding of streamflow variation induced by degrading permafrost in different river basins. We therefore used a deep learning model to simulate the long-term(≥ 30 years) monthly streamflow at 60 hydrological stations along the Lena River, the third longest circum-Arctic river. Analyzing the effects of precipitation, temperature, and thaw depth on streamflow variation throughout the Lena River Basin, we identified two feedback patterns relating streamflow to warming permafrost, observed in areas of continuous and discontinuous permafrost. In northern plain regions with continuous permafrost, 94% of stations presented an increasing trend in annual streamflow from the 1900s to the 2010s due to permafrost degradation. The enhanced streamflow was mainly due to increased meltwater in the flood season. In southern regions covered by both continuous and discontinuous permafrost, approximately 38% of stations exhibited a declining trend in annual streamflow in response to permafrost degradation, with a high proportion(61%) located in mountain regions(elevation ≥ 500 m). The decline is attributed to the enhanced infiltration capacity of thawing frozen layers within discontinuous permafrost regions. Our study provides new insights into the mechanisms behind permafrost degradation-induced streamflow variation and highlights the importance of formulating tailored strategies for sustainable river management in cold regions experiencing climate change.

关键词： permafrost degradation streamflow variation deep learning model climate change large cold basin

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Identification of the non-stationarity of extreme temperature events and teleconnections with solar activity and large-scale atmospheric circulation: A case study in the Yangtze River Economic Belt

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Journal of Earth Science 2024年

作者： Lin Zhang Jingyun Ling Shengzhi Huang Hongbin Zhan Yi Wu Menggui Jin Qiang Huang State Key Laboratory of Eco-hydraulics in Northwest Arid Region， Xi'an University of Technology College of Design and Engineering， National University of Singapore Yinshanbeilu Grassland Eco-Hydrology National Observation and Research Station， China Institute of Water Resources and Hydropower Research Department of Geology and Geophysics， Texas A&M University， College Station School of Earth System Science， Tianjin University School of Environmental Studies， China University of Geosciences

In recent decades， extreme climate events have become a major problem worldwide. To understand the uncertainty in the response of extreme events to global warming， regional assessments are required for various climatic and geographic regions. The spatiotemporal distribution of extreme temperature events in the Yangtze River Economic Belt (YREB) from 1960 to 2019， including interannual changes and their teleconnections with solar activity and large-scale atmospheric circulation， were analyzed using eight indices of extreme temperature events. Over the past six decades， the climate in the YREB region has seen a warming trend， characterized by an increase in extreme warm events and a decrease in extreme cold events. The extreme temperature indices exhibit strong spatial variability. The warm extremes display a significant upward trend across the YREB， while cold extremes are primarily concentrated in the western part of the region. In recent decades， both warm and cold extremes have significant interannual variations， and these events predominantly oscillate over periods of less than four years. After 1985， the relationship between El Ni?o-Southern Oscillation (ENSO)， Arctic Oscillation (AO)， Pacific Decadal Oscillation (PDO) and extreme temperature events has changed significantly compared with pre-1985， and the direction of the phase angle can determine the positive and negative effects of the two time-series. ENSO， AO and PDO mainly have positive impacts on extreme temperature events， with ENSO and AO exerting greater impacts than PDO. In contrast， solar activity mainly has a negative impact on these events. Furthermore， the notable interdecadal changes in extreme temperature events， especially warm extremes， may be caused by the shift in the PDO phase. Therefore， the results of the study are important for the YREB region to take effective measures to mitigate the potential impacts of human activities on regional warming.

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Basin-scale exposure risk of psychiatric pharmaceuticals and illicit drugs in tap water in Eastern China

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Emerging Contaminants 2024年第3期10卷 40-45页

作者： Wei Wang Zeyuan Wang Feng Chen Fangxing Yang Zhejiang Institute of hydraulics&Estuary(Zhejiang Institute of Marine Planning and Design) Hangzhou310008China Key Laboratory of Marine Ecosystem Dynamics Second Institute of OceanographyMinistry of Natural ResourcesHangzhou310012China Key Laboratory of Environment Remediation and Ecological Health Ministry of EducationCollege of Natural Resources and Environmental ScienceZhejiang University310058HangzhouChina Hangzhou Ecological and Environmental Monitoring Center of Zhejiang Province 310058HangzhouChina Innovation Center of Yangtze River Delta Zhejiang University314100JiashanChina

A total of twenty-three psychiatric pharmaceuticals and illicit drugs were analyzed in tap water covering seven basins in Eastern *** residual concentrations of these substances were detected up to 22.4 ng L^(-1).Among the substances,benzodiazepines were more often detected with higher median concentrations than those of illicit ***,the higher residual levels of psychoactive substances were detected in the upstream of the basins compared with the *** example,the concentrations of diazepam,temazepam,and oxazepam in the downstream were much higher than those in the upstream in *** the basins,YH was the most polluted *** assessment indicated the median exposure doses of diazepam and temazepam were from 85 to 99 and 3.5e4.1 pg kg^(-1) bw d^(-1) in the basins,*** quotient for the nine detected substances was calculated in each basin with the range from 0.0001 to 0.0389,indicating low risk in the tap water for human health under current concentrations.

关键词： Psychiatric pharmaceuticals Illicit drugs Psychoactive substances Tap water Risk assessment

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Novel Heat Transfer Issues Associated with the Design and Safe Operation of the MEGAPIE Spallation Source Target

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Journal of Thermal Science 2007年第1期16卷 63-78页

作者： Brian L.Smith Thermal hydraulics Laboratory Paul Scherrer InstituteSwitzerland

Critical heat transfer problems are discussed in the context of the operation of a spallation source target, which represents a first demonstration of the feasibility of an innovative concept for generating energy using a particle accelerator. Within the framework of the umbrella project MEGAPIE, an R＆D support group was organized to take responsibility for target cooling. This involved the use of advanced numerical methods - Computational Fluid Dynamics （CFD） and Finite Element Method （FEM） - validated against suitable experimental data, and by means of appropriate benchmarking exercises. The design studies using CFD resulted in an optimum flow configuration being defined for the coolant circulation. Flow visualization tests were undertaken using a glass/water test section, with the velocity field mapped using optical and ultrasonic measuring techniques. These were followed by heat transfer tests, using the actual target materials （lead-bismuth-eutectic coolant and steel confinement）. Further CFD/FEM work to analyze operational transients and accident sequences was also carded out, and is described in the paper.

关键词： computational fluid dynamics finite element method liquid-metal coolant spallation source target

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Climatic and anthropogenic impacts on the decrease of sediment discharge to the Mediterranean coast from the largest river of Maghreb

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International Journal of Sediment Research 2021年第2期36卷 268-278页

作者： Ali Hadour Gil Mahé Mohamed Meddi National High School of hydraulics

The current study focuses on the issue of the decrease in sediment discharge to the Mediterranean Sea by the largest river in Algeria, the Wadi Cheliff(i.e. Cheliff River). This study clarifies the effect of climatic and anthropogenic factors on the changes in the sedimentary dynamics of the Cheliff River discharging to the sea. The data used(rainfall, water discharge, and sediment discharge) concern the Sidi Bel Attar gaging station on the Cheliff River, only 18 km from discharge to the Mediterranean Sea. A power-type statistical regression model was used to fill the 74.2% gap in Suspended Solids(SS) measurements in the establishment of a SS database for the period 1951 e2012. The study results show that the transport of suspended sediment discharged to the sea is about 487 t/km2/yr. Statistical tests of breaks highlight that rainfall decreased by 26% and that water and sediment input to the sea declined from 74% to 63% for the period of 1981 e2012. The correlation analysis shows a decrease in the contribution of rainfall on sediment and water input at the outlet equal to 77.9% and 77.8%, respectively, during the period of 1980 e2012, compared to the period of 1968 e1980. However, the double mass method reflects the contribution of factors other than rainfall to the decrease of sediment input to the sea. These other factors mainly include large dams, which intercepted about 71% of the total volume of sediment discharged to the sea during the period of 1968 e2010. In addition the contribution of large dams to the reduction of sedimentary input to the sea is more important than that of the decrease in rainfall. The management of large dams also contributes to the increase in the sediment deficit to the sea through the prioritization of interception of sediment at the expense of releases, for socio-economic purposes, 68.4% of the Cheliff River discharge is diverted for human use. This has led to an increase in the mean water bed level at bankfull downstream, where the

关键词： Sediment discharge Cheliff River Algeria North Africa Dams Mediterranean Sea

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Predicting the spatial distribution of soil erodibility factor using USLE nomograph in an agricultural watershed,Ethiopia

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International Soil and Water Conservation Research 2015年第4期3卷 282-290页

作者： Hailu Kendie Addis Andreas Klik Institute of hydraulics and Rural Water Management University of Natural Resources and Life SciencesViennaAustria Gondar Agricultural Research Center Soil and Water Management DirectorateGondarEthiopia

Soil erosion in the northwestern Amhara region,Ethiopia has been a subject of anxiety,resulting in a major environmental threat to the sustainability and productive capacity of agricultural *** study tried to estimate soil erodibility factor(Kfactor)using Universal Soil Loss Equation(USLE)nomograph,and evaluate the spatial distribution of the predicted K-factor in a mountainous agricultural *** investigate the K-factor,the 54 km2 study watershed was divided into a 500 m by 500 m square grid and approximately at the center of each grid,topsoil samples(roughly 10 to 20 cm depth)were collected over 234 ***,silt,clay and organic matter(OM)percentage were analyzed,while soil permeability and structure class codes were obtained using the United States Department of Agriculture(USDA)*** resulting coefficient of variation(CV)of the estimated K-factor was 0.31,suggesting a moderate ***,the value of nugget to sill ratio of K-factor was 0.32,which categorized as moderate spatial *** accuracy and model fitting effect of the Gaussian semivariogram approach was best,suggesting that the Gaussian ordinary Kriging model was more appropriate for predicting *** resulting value of the mean error(ME)was 0 and the mean squared deviation ratio(MSDR)was nearly 1,which indicates the Gaussian model was unbiased and reproduced the experimental variance *** values of K-factor were smaller(0.0217 to 0.0188)in the northern part and gradually increased(0.0273 to 0.033 Mg h MJ^(-1)mm^(-1))towards the central and south of the study watershed.

关键词： Nomograph Semivariogram Soil erodibility factor Spatial variability Watershed

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Effects of river width changes on flow characteristics based on flume experiment

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Journal of Mountain Science 2016年第2期13卷 361-368页

作者： WANG Xie-kang WANG Bing-jie LIU Xing-nian Zhang Li-qiong State Key Laboratory of hydraulics and Mountain River Engineering Sichuan University Hydrology and hydraulics Section South Florida Water Management District

The rapid changes in flow pattern due to varying channel widths will make significantly impact on the hydraulic structures and evolutions of open channel. To better understand the impact of varying width, a flume experiment with adjustable width and a depth-averaged two-dimension numerical model were used to analyze the variations of flow parameters. Our experimental results showed that flow velocity gradually increased with decreasing water depth in converging region, and decreased with increasing water depth in diverging zones. It was also found that the turbulence intensity laws in three directions were not agreed with the theoretical relationships proposed by Nezu and Nakagawa in 1993 in straight open channel flows. The flow in the channel with varying width may change from the supercritical flow to the subcritical flow as a function of Froude number. Our numerical simulations with different flow rates showed that most of the hydraulic jumps in diverging region were submerged jump and the degree of submergence increased with increasing flow rate in gradual channel transition. When the flow rate increased, the range of supercritical flow rapidly decreased and the flow changed from the supercritieal condition to the subcritical condition in diverging sections.

关键词： Gradual channel transition Flow pattern Experimental study Numerical simulation

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THREE-DIMENSIONAL NUMERICAL SIMULATION OF INTAKE MODEL WITH CROSS FLOW

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Journal of Hydrodynamics 2011年第3期23卷 314-324页

作者： HSIAO Shih-Chun Department of hydraulics and Ocean Engineering National Cheng Kung University

The hydrodynamics of a pump sump consisting of a main channel, pump sump, and intake pipe is examined using Truchas a three-dimensional Navier-Stokes solver, with a Large Eddy Simulation （LES） turbulence model. The numerical results of streamwise velocity profiles and flow patterns are discussed and compared with experimental data of Ansar and Nakato. Fairly good agreement is obtained. Furthermore, unlike Ansar et al.＇s inviscid solution, the proposed numerical model includes the effect of fluid viscosity and considers more realistic simulation conditions. Simulation results show that viscosity affects the prediction of flow patterns and that the streamwise velocity can be better captured by including cross flow. The effects of the submergence Froude number on the free surface and streamwise velocity are also examined. The free surface significantly fluctuates at high submergence Froude number flows and the corresponding distribution of streamwise velocity profiles exhibits a trend different from that obtained for low submergence Froude number flows.

关键词： pump sump cross flow submergence Froude number Large Eddy Simulation (LES)

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Activation of peroxymonosulfate by FeVO_(3-x)for the degradation of carbamazepine:Vanadium mediated electron shuttle and oxygen vacancy modulated interface chemistry

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Chinese Chemical Letters 2024年第1期35卷 435-440页

作者： Leiduo Lai Hongyu Zhou Yichen Hong Mengfan Luo Yang Shi Heng Zhang Zhaokun Xiong Gang Yao Bo Lai State Key Laboratory of hydraulics and Mountain River Engineering College of Architecture and EnvironmentSichuan UniversityChengdu 610065China Sino-German Centre for Water and Health Research Sichuan UniversityChengdu 610065China Chengdu Baixi Environmental Technology Company Chengdu 610065China d Institute of Environmental Engineering RWTH Aachen UniversityGermany

Fast Fe(III)/Fe(II)circulation in heterogeneous peroxymonosulfate(PMS)activation remains as a bottleneck issue that restricts the development of PMS based advanced oxidation ***,we proposed a facile ammonia reduction strategy and synthesized a novel FeVO3-x catalysts to activate PMS for the degradation of a typical pharmaceutical,carbamazepine(CBZ).Rapid CBZ removal could be achieved within 10 min,which outperforms most of the other iron or vanadium-based *** paramagnetic resonance analysis and chemical probe experiments revealed SO_(4)^(·-),·OH,O_(2)^(·-)and high valent iron(Fe(IV))were all generated in this system,but SO4·-and Fe(IV)primarily contributed to the degradation of ***,X-ray photoelectron spectroscopy and X-ray adsorption spectroscopy indicated that both the generated low-valent V provides and oxygen vacancy acted as superior electron donors and accelerated internal electron transfer via the unsaturated V-O-Fe ***,the proposed system also exhibited satisfactory performance in practical *** work provides a promising platform in heterogeneous PMS activation.

关键词： Peroxymonosulfate Fe(III) Fe(II)cycle Electron shuttles Oxygen vacancy Bimetallic catalysts

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地理大数据挖掘——“水-能源-粮食”纽带研究的新机遇

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Journal of Geographical Sciences 2024年第2期34卷 203-228页

作者：杨洁曹小曙姚俊康喆文畅建霞王义民 Northwest Land and Resources Research Center Global Regional and Urban Research InstituteInstitute ofTransport Geography and Spatial PlanningShaanxi Normal UniversityXi’an 710119China Hanjiang-to-Weihe River Valley Water Diversion Project Construction Co.Ltd. Shaanxi ProvinceXi’an710010China State Key Laboratory of Eco-hydraulics in Northwest Arid Region Xi’an University of TechnologyXi’an710048China

Since the Bonn 2011 conference,the“water-energy-food”(WEF)nexus has aroused global concern to promote sustainable *** WEF nexus is a complex,dynamic,and open system containing interrelated and interdependent ***,the nexus studies have mainly focused on natural elements based on massive earth observation *** elements(e.g.,society,economy,politics,culture)are described insufficiently,because traditional earth observation technologies cannot effectively perceive socioeconomic characteristics,especially human feelings,emotions,and ***,it is difficult to simulate the complex WEF *** the development of earth observation sensor technologies and human activity perception methods,geographical big data covering both human activities and natural elements offers a new opportunity for in-depth WEF nexus *** study proposes a five-step framework by leveraging geographical big data mining to dig for the hidden value in the data of various natural and human *** framework can enable a thorough and comprehensive analysis of the WEF *** application examples of the framework,major challenges,and possible solutions are *** big data mining is a promising approach to enhance the analysis of the WEF nexus,strengthen the coordinated management of resources and sectors,and facilitate the progress toward sustainable development.

关键词： geographical big data data mining “water-energy-food”nexus interaction mechanisms sustainability resources security

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