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Linkage between permafrost distribution and river runoff changes across the Arctic and the Tibetan Plateau

Science China Earth Sciences 2020年第2期63卷 292-302页

作者： Chunlin SONG Genxu WANG tianxu mao Junchen DAI Daqing YANG Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100049China College of Forestry Guizhou UniversityGuiyang 550025China National Hydrology Research Centre Environment CanadaSaskatoon SK S7N 3H5Canada

River runoff in the Arctic and the Tibetan Plateau(TP) change significantly in recent decades. However, the mechanisms of the physical processes of permafrost river runoff change remain uncertain across large scale. This study investigated the mainstreams and tributaries of main Arctic and TP rivers dominated by permafrost and assessed the linkage between hydrological regime change and permafrost. The results show that the effects of permafrost on river runoff are highly dependent on the permafrost coverage of a watershed. For the past decades, the majority of the Arctic and TP basins showed increased discharge, while all of the studied basins showed increased baseflow, with faster increasing speed than total *** total discharge and baseflow annual change rate(ΔQ and ΔBF) increased with permafrost coverage, indicating the increments of streamflow are enhanced with high permafrost coverage. Meanwhile, the annual change of precipitation showed weak connection with total discharge and baseflow change. The high permafrost coverage basins showed high annual maximum/minimum discharge ratio(Qmax/Qmin), while the Qmax/Qminchanged slightly in low permafrost cover basins. Our results highlight the importance of permafrost coverage on streamflow regime change for permafrost basins across the northern hemisphere. Due to these linkage between permafrost extent and runoff regime change and the increasing changes of permafrost, more attention should be paid to the change of hydrological processes in permafrost-underlain basins.

关键词： Permafrost hydrology Arctic rivers Tibetan Plateau rivers Permafrost degradation Runoff change

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Seasonal dynamics of suprapermafrost groundwater and its response to the freeing-thawing processes of soil in the permafrost region of Qinghai-Tibet Plateau

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Science China Earth Sciences 2015年第4期58卷 727-738页

作者： CHANG Juan WANG GenXu LI ChunJie mao tianxu College of Earth and Environment Science Lanzhou University Institute of Mountain Hazards and Environment Chinese Academy of Sciences

The suprapermafrost groundwater in permafrost region not only is an important component of the water cycle and land surface process, but also is closely associated with the charges of ecological environment in cold region. However, the seasonal dynamics, driving factors, and mechanism of suprapermafrost groundwater are not well understood. Based on observation at slope scale on suprapermafrost groundwater dynamics of typical alpine meadows in the Qinghai-Tibet Plateau, the seasonal dynamics, spatial distribution and driving factors of suprapermafrost groundwater were analyzed. The results showed that there were close relationships between the seasonal dynamics of suprapermafrost groundwater and the freezing-thawing processes of active soil in permafrost region. The seasonal dynamics of suprapermafrost groundwater and its slope distribution pattern were controlled by soil temperature of active layers. The phase and range of the suprapermafrost groundwater dynamics are determined by deep soil(below 60 cm depth) moisture and groundwater recharging sources. The relationship between active soil temperatures and dynamics of suprapermafrost groundwater levels was better described by Boltzmann functions. However, the influencing thresholds of soil temperature on groundwater dynamics varied at different depths of active layers and in different slope positions, which resulted in the significant spatial heterogeneity of suprapermafrost groundwater dynamics in slope scale. Land cover change and global warming certainly altered the dynamics of suprapermafrost groundwater and the hydraulic interaction between groundwater and rivers, and consequently altered the overall hydrologic cycle of watershed scale.

关键词： suprapermafrost groundwater seasonal dynamics soil hydrothermal characteristics freezing-thawing process

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添加生物质炭对喀斯特地区黄壤饱和导水率的影响

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水土保持研究 2021年第5期28卷 108-113,120页

作者：屠丹毛天旭贵州大学林学院贵阳550025

为探究添加生物质炭对喀斯特坡耕地黄壤饱和导水率的影响,在室内条件下测定了不同添加量(质量分数为0,1%,2%,3%)、不同粒径(粒径大小为1 mm)的玉米秸秆生物质炭(CSB)和稻壳生物质炭(RHB)添加后的土壤容重、孔隙度、持水量和饱和导水率... 详细信息

为探究添加生物质炭对喀斯特坡耕地黄壤饱和导水率的影响,在室内条件下测定了不同添加量(质量分数为0,1%,2%,3%)、不同粒径(粒径大小为1 mm)的玉米秸秆生物质炭(CSB)和稻壳生物质炭(RHB)添加后的土壤容重、孔隙度、持水量和饱和导水率。结果显示:添加生物质炭显著降低了土壤容重,与对照(CK)相比,添加相同含量的CSB和RHB后土壤容重分别降低了5.13%和4.85%,随着添加量增加,土壤容重呈减小趋势,而土壤总孔隙度和毛管孔隙度呈增大趋势。添加CSB和RHB后土壤的田间持水量(FMC)提高了5.30%和4.72%,毛管持水量(CWC)提高了4.75%和6.60%,随着添加量增加、粒径增大,土壤的FMC和CWC呈增大趋势。土壤饱和导水率的变化与生物质炭的粒径有关,添加1 mm粒径CSB和RHB,土壤饱和导水率增加了66.67%和33.33%,添加0.25~1 mm粒径的生物质炭,土壤饱和导水率无明显的变化规律。本研究得出,添加生物质炭可以显著降低土壤容重,提高土壤田间持水量和毛管持水量,改善土壤的导水性能,研究结果可为生物质炭在喀斯特地区坡耕地黄壤结构改良的应用中提供理论依据。

关键词：生物质炭黄壤田间持水量毛管持水量饱和导水率

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Simulation and evaluation study of atmospheric aerosol nonsphericity as a function of particle size

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Particuology 2024年第7期90卷 281-291页

作者： Qianjun mao Xin Nie School of Urban Construction Wuhan University of Science and TechnologyWuhan430065China College of New Energy and Materials Northeast Petroleum UniversityDaqing163318China

Aerosol nonsphericity causes great uncertainty in radiative forcing assessments and climate *** considerable studies have attempted to quantify this uncertainty,the relationship between aerosol nonsphericity and particle size is usually not considered,thus reducing the accuracy of the *** this study,a coupled inversion algorithm combining an improved stochastic particle swarm optimization algorithm and angular light scattering is used for the nonparametric estimation of aerosol nonsphericity variation with particle size,and the optimal sample selection method is employed to screen the *** on the verification of inversion accuracy,the variation of aerosol aspect ratio with particle size based on the ellipsoidal model in global regions has been obtained from Aerosol Robotic Network(AERONET)data,and the effect of nonsphericity on radiative forcing and dry deposition has been *** results show that the aspect ratio increases with particle size in all regions,with the maximum ranging from 1.4 to 1.8 in the desert,reflecting the differences in aerosol composition at different particle *** radiation calculations,considering aerosol nonsphericity makes the aerosol cooling effect weaker and surface radiative fluxes increase,but hardly changes the aerosol absorption,with maximum differences of 9.22%and 22.12%at the bottom and top of the atmosphere,***,the differences in radiative forcing between aspect ratios as a function of particle size and not varying with particle size are not significant,averaging less than 2%.Besides,the aspect ratio not varying with particle size underestimates the deposition velocity of small particles and overestimates that of large particles compared to that as a function of particle size,with maximum differences of 7%and 4%,respectively.

关键词： Aerosol nonsphericity Inversion Aspect ratio Radiative forcing Dry deposition velocity

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Pressure-induced hydrogen-dominant high-temperature superconductors

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National Science Review 2024年第7期11卷 14-16页

作者： Ho-kwang mao Shanghai Advanced Research in Physical Sciences Center for High Pressure Science and Technology Advanced Research

Recent studies of hydrogen-dominant（superhydride） materials have led to putative discoveries of near-room temperature superconductivity at high pressures. The idea started more than half-a-century ago as a by-product of the quest for metallic hydrogen for which a natural consequence of its very high Debye temperature and phonon frequency due to the very low mass of the hydrogen atoms would lead to a high superconducting critical temperature （Tc） in weak coupling Bardeen-Cooper-Schrieffer（BCS） expression.

关键词： HYDRIDE LANTHANUM

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Proof of Two Supercongruences of Truncated Hypergeometric Series_(4)F_(3)

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Acta Mathematica Sinica,English Series 2024年第4期40卷 1015-1028页

作者： Guo Shuai mao Department of Mathematics Nanjing University of Information Science and TechnologyNanjing 210044P.R.China

In this paper,we prove two supercongruences conjectured by Z.-*** via the Wilf-Zeilberger *** of them is,for any prime p>3,4F3[7/6 1/2 1/2 1/2 1/6 1 1]-1/8]-1/2≡p(-2/p)+p^(3)/4(2/p)Ep-3 (mod p^(4))where(·/p)stands f... 详细信息

关键词： Supercongruence truncated hypergeometric series Wilf–Zeilberger method Euler numbers Legendre symbol

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青藏高原多年冻土区不同草地类型生态系统呼吸季节差异性

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冰川冻土 2018年第6期40卷 1255-1264页

作者：张涛王根绪杨燕毛天旭中国科学院/水利部成都山地灾害与环境研究所山地表生过程与生态调控重点实验室四川成都610041 中国科学院大学北京100049

研究多年冻土区不同草地类型及季节生态系统呼吸,对理解青藏高原碳源汇关系及其对气候变化响应具有重要意义。在青藏高原风火山选取高寒草甸和沼泽草甸对生长季和非生长季生态系统呼吸进行观测。结果表明:生态系统呼吸呈明显的日变化和... 详细信息

研究多年冻土区不同草地类型及季节生态系统呼吸,对理解青藏高原碳源汇关系及其对气候变化响应具有重要意义。在青藏高原风火山选取高寒草甸和沼泽草甸对生长季和非生长季生态系统呼吸进行观测。结果表明:生态系统呼吸呈明显的日变化和季节变化,高寒草甸日变异系数(0. 30～0. 92)高于沼泽草甸(0. 12～0. 29),高寒草甸非生长季生态系统呼吸白天/晚上比高于生长季,而沼泽草甸季节变化较小;季节变化与5 cm地温变化一致。高寒草甸和沼泽草甸非生长季生态系统呼吸平均速率分别为0. 31和0. 36μmol·m^(-2)·s^(-1),生长季分别为1. 99和2. 85μmol·m^(-2)·s^(-1)。沼泽草甸生态系统呼吸年排放总量为1 419. 01 gCO_2·m^(-2),显著高于高寒草甸(1 042. 99 gCO_2·m^(-2)),其中非生长季高27%,生长季高39%。高寒草甸和沼泽草甸非生长季生态系统呼吸总量分别为268. 13和340. 40 gCO_2·m^(-2),分别占全年的25. 71%和23. 99%。两种草地类型生态系统呼吸与气温、5 cm和20 cm地温均显著相关,可解释37%～73%的季节变异,除生长季沼泽草甸外,生态系统呼吸与5 cm地温相关性最高。非生长季5 cm地温对应Q_(10)为4. 34～5. 02,高于生长季(2. 35～2. 75),且沼泽草甸高于高寒草甸。生长季生态系统呼吸与土壤水分无显著关系,而非生长季生态系统呼吸受土壤水分显著影响(R^2:0. 21～0. 40),随土壤水分增加而增加。

关键词： CO2通量温度敏感性指数(Q10) 高寒草甸沼泽草甸非生长季

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One bird,multiple stones:The race to find a gene of dominant negative effect in wheat

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The Crop Journal 2024年第4期12卷 951-952页

作者： Long mao State Key Laboratory of Crop Gene Resources and Breeding Institute of Crop SciencesChinese Academy of Agricultural SciencesBeijing 100081China

In the current issue of The Crop Journal,Chen et al.[1]reports map-based cloning of a wheat gene that showed temperaturedependent pleiotropic effects on multiple traits including plant height,leaf shape,spike and grain morphology,and accordingly was named WPA1 for Wheat Plant Architecture *** mutant was first observed among EMS-treated plants and repeatedly appeared in multiple occasions.

关键词： Wheat bird repeatedly

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Dynamic steric confinement effect expands the frontier of Cu-catalyzed asymmetric propargylic aminations

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Science China Chemistry 2024年第10期67卷 3181-3183页

作者： Peng Chen mao-mao Zhang Wen-Jing Xiao Liang-Qiu Lu Engineering Research Center of Photoenergy Utilization for Pollution Control and Carbon Reduction Ministry of EducationCollege of ChemistryCentral China Normal UniversityWuhan 430079China Wuhan Institute of Photochemistry and Technology Wuhan 430082China State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical Physics(LICP)Chinese Academy of SciencesLanzhou 730000China School of Chemistry and Chemical Engineering Henan Normal UniversityXinxiang 453007China

Chiralα-tertiary amines and related azacycles are commonly found in many natural products,pharmaceuticals and agrochemicals[1].Copper-catalyzed asymmetric propargylic amination(APA)reactions have been established as a reliable method to access enantio-enriched propargylic amines,largely due to the seminal contribution of Nishibayashi et al.[2]and van Maarseveen et al.[3]in 2008.

关键词： catalyzed asymmetric amines

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Heat Storage Performance of PCM in a Novel Vertical Pointer-Shaped Finned Latent Heat Tank

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Journal of Thermal Science 2024年第2期33卷 422-434页

作者： mao Qianjun ZHU Yuanyuan LI Tao School of Urban Construction Wuhan University of Science and TechnologyWuhan430065China

The heat storage performance of latent heat storage systems is not good due to the poor thermal conductivity of phase change *** this paper,a new type of pointer-shaped fins combining rectangular and triangular fins has been employed to numerically simulate the melting process in the heat storage tank,and the fin geometry parameter effects on heat storage performance have been *** results indicate that compared with the bare tube and the rectangular finned tank,the melting time of the phase change material in the pointer-shaped finned tank is reduced by 64.2%and 15.1%,*** closer the tip of the triangular fin is to the hot wall,the better the heat transfer *** optimal height of the triangular fin is about 8 *** the number of fins from 4 to 6 and from 6 to 8 reduces the melting time by 16.0%and 16.7%***,increasing the number of fins from 8 to 10 only reduces the melting time by 8.4%.When the fin dimensionless length is increased from 0.3 to 0.5 and from 0.5 to 0.7,the melting time is shortened by 17.5%and 13.0%.But the melting time is only reduced by 2.9%when the dimensionless fin length is increased from 0.7 to *** optimising the design of the thermal storage system,the results can provide a reference value.

关键词： thermal energy storage phase change material pointer-shaped fins heat storage performance

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