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Viscoelasticity and shear resistance at the aggregate scale of structured and organic carbon-free Chernozems

Pedosphere 2023年第5期33卷 754-764页

作者： Christoph HAAS Rainer HORN Philipp SAGGAU Rainer DUTTMANN Institute for Plant Nutrition and Soil Science University of KielKiel 24118Germany Department of Geography Division of Landscape Ecology and Geoinformation SciencesUniversity of KielKiel 24118Germany

Soil rheology characterises the flow behaviour of soils at the particle-particle to aggregate *** sweep tests(ASTs)are often the method of choice for parameterizing soil flow properties,such as the shear strain values at the end of the linear viscoelastic range(i.e.,the deformation is mainly elastic)and at the yield point(i.e.,elastic equals plastic deformation).Samples from seven soil profiles and five soil depths of Chernozems,collected in the Maidanetske study area,close to Uman City of Ukraine,were analysed to evaluate the effect of soil organic carbon(SOC)on the parameters related to soil microstructural stability derived from *** organic carbon was removed with H_(2)O_(2)to determine the soil texture-dependent values of soil rheological properties,which were compared to the values determined for samples with intact water-stable *** shear resistance-related parameters increased for aggregated soil samples compared to SOC-free soil samples,indicating an increase in soil stability due to *** contrast,the values of the overall viscoelasticity and the shear strain were reduced for aggregated soil samples,indicating decreased soil *** functions were applied to predict the shear strain-dependent loss and storage moduli and shear stress values as a function of SOC *** particles(630–2000μm)and volumetric water content improved the *** conclude that increased SOC content,through the gluing and cementing effects of SOC and altered aggregate shapes compared to SOC-free soil materials,contributes to higher microstructural ***,the increased water content in the SOC-containing soil samples reversed soil strengthening *** was due to the fact that a more rapid increase in positive water pressure under shear stress weakened the samples and the spherical aggregates began to rotate more easily,thus loosing energy,when compared to platy particles of the SOC-free soil materials.

关键词： aggregation rheology shear strain shear stress soil organic carbon depletion soil stability

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An Objective Approach to Generating Multi-Physics Ensemble Precipitation Forecasts Based on the WRF Model

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Journal of Meteorological Research 2020年第3期34卷 601-620页

作者： Chenwei SHEN Qingyun DUAN Wei GONG Yanjun GAN Zhenhua DI Chen WANG Shiguang MIAO State Key Laboratory of Earth Surface Processes and Resource ecology Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875 State Key Laboratory of hydrology–Water Resources and Hydraulic Engineering and College of hydrology&Water Resources Hohai UniversityNanjing 210098 State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081 South China Botanical Garden Chinese Academy of SciencesGuangzhou 510650 Institute of Urban Meteorology China Meteorological AdministrationBeijing 100081

Selecting proper parameterization scheme combinations for a particular application is of great interest to the Weather Research and Forecasting(WRF)model *** study aims to develop an objective method for identifying a set of scheme combinations to form a multi-physics ensemble suitable for short-range precipitation forecasting in the Greater Beijing *** ensemble is created by using statistical techniques and some *** initial sample of 90 scheme combinations was first generated by using Latin hypercube sampling(LHS).Then,after several rounds of screening,a final ensemble of 40 combinations were *** ensemble forecasts generated for both the training and verification cases using these combinations were evaluated based on several verification metrics,including threat score(TS),Brier score(BS),relative operating characteristics(ROC),and ranked probability score(RPS).The results show that TS of the final ensemble improved by 9%-33%over that of the initial *** reliability was improved for rain≤10 mm day^-1,but decreased slightly for rain>10 mm day^-1 due to insufficient *** resolution remained about the *** final ensemble forecasts were better than that generated from randomly sampled scheme *** results suggest that the proposed approach is an effective way to select a multi-physics ensemble for generating accurate and reliable forecasts.

关键词： ensemble precipitation forecast Weather Research and Forecasting(WRF)model multi-physics verification bootstrapping

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Photosynthetic and water-related physiological characteristics of Periploca sepium in response to changing soil water conditions in a shell sand habitat

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Journal of Forestry Research 2023年第2期34卷 453-467页

作者： Xiao Wang Jiangbao Xia Ximei Zhao Mingming Dong Xianshuang Xing Ying Fang Qinqin Fu Zhaohua Lu Institute of Restoration ecology School of Chemical and Environmental EngineeringChina University of Mining and Technology(Beijing)Beijing 100083People’s Republic of China Shandong Provincial Key Laboratory of Eco-Environmental Science for Yellow River Delta Binzhou UniversityBinzhou 256603People’s Republic of China Shandong hydrology Center Jinan 250013People’s Republic of China

This study was performed to observe the effects of water on photosynthesis and water-related physiology in dominant shrubs in shell sand ***-year-old Periploca sepium seedlings were used as model species.A gradient of 12 water levels was established by artificially supplying the shell sand with water up to saturation and then allowing natural evapotranspiration to *** photo synthetic,chlorophyll fluorescence and stem sap flow parameters of *** were measured under a range of water *** different soil water conditions were classified according to the responses of these parameters.(1)With the increase in the relative water content(RWC)of the shell sand,the parameters of leaf photosynthesis,chlorophyll fluorescence and water-related physiology in *** showed significant critical *** net photo synthetic rate(Pn),transpiration rate(Tr),instantaneous water use efficiency(WUE),potential water use efficiency(WUEi),maximum photochemical efficiency(Fv/Fm),actual photochemical efficiency(ΦPSII)and daily accumulation of stem sap flow all increased first and then decreased with increasing RWC,but the corresponding water conditions associated with their maximum values were not the *** RWC of 69.40%was determined to be the optimal water condition for photosynthesis and water-related physiological activity in *** an RWC of 36.61%,the mechanism of photosynthetic inhibition in *** changed from stomatal limitation to nonstomatal limitation;this was also the minimum water requirement for maintaining normal photo synthetic *** RWC of 50.27%resulted in the highest WUE in ***,indicating that moderate drought stress increased WUE.(2)Based on the quantitative relationship between the photo synthetic parameters of *** and the shell sand water gradient,the soil water availability was classified into 6 water *** RWC range for maintaining strong photosynthesis and high WUE in *** was 63.22-69.98%.(3)Gas

关键词： Water gradient range Periploca sepium Photosynthesis Water physiology Water availability classifi cation Shell sand

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Comparison of precipitation and evapotranspiration of five different land-cover types in the high mountainous region

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Research in Cold and Arid Regions 2017年第6期9卷 622-630页

作者： Yong Yang RenSheng Chen YaoXuan Song ChunTan Han JunFeng Liu ZhangWen Liu Qilian Alpine ecology and hydrology Research Station Key Laboratory of Ecohydrology Inland River BasinNorthwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu 730000China

Many rivers originate in high mountainous regions. However, the effects of climate warming on the runoff and water balance in these regions remain unclear due to the lack of observational data from harsh environments, and the variable influences of climate change on alpine land-cover types with different water balances. Using observations and simulations from Coup Model, water-balance values collected at five alpine land-cover types(steppe, shrub meadow, moist meadow, swamp meadow, and moraine) in a small alpine watershed, the Qilian Mountains in Northwest China, from October 2008 to September 2014, were compared. Measured evapotranspiration, multilayer soil temperatures and water contents, and frozen-depth data were used to validate Coup Model outputs. The results show that elevation is the primary influence on precipitation, evapotranspiration, and runoff coefficients in alpine regions. Land-cover types at higher elevations receive more precipitation and have a larger runoff coefficient. Notably, climate warming not only increases evapotranspiration but also particularly increases the evapotranspiration/precipitation ratio due to an upward shift in the optimum elevation of plant species. These factors lead to decrease runoff coefficients in alpine basins.

关键词： global warming land-cover types water balance elevation runoff coefficient

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Hydrological modelling in the anthroposphere: predicting local runoff in a heavily modified high-alpine catchment

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Journal of Mountain Science 2018年第5期15卷 921-938页

作者： Johannes WESEMANN Mathew HERRNEGGER Karsten SCHULZ Institute of Water Management Hydrology and Hydraulic Engineering (IWHW) University of Natural Resources and Life Sciences Vienna (BOKU)

Hydrological models within inflow forecasting systems for high-alpine hydropower reservoirs can provide valuable information as part of a decision support system for the improvement of hydropower production or flood retention. The information, especially concerning runoff, is however rarely available for the calibration of the hydrological models used. Therefore, a method is presented to derive local runoff from secondary information for the calibration of the model parameters of the rainfallrunoff model COSERO. Changes in water levels in reservoirs, reservoir outflows, discharge measurements at water intakes and in transport lines are thereby used to derive the local, "natural" flow for a given sub-catchment. The proposed method is applied within a research study for the ?BB Infrastructure Railsystem division in the Stubache catchment in the central Austrian Alps. Here, the ?BB operates the hydropower scheme "Kraftwerksgruppe Stubachtal", which consists of 7 reservoirs and 4 hydropower stations. The hydrological model has been set up considering this human influences and the high natural heterogeneity in topography and land cover, including glaciers. Overall, the hydrological model performs mostly well for the catchment with highest NSE values of 0.78 for the calibration and0.79 for the validation period, also considering the use of homogeneous parameter fields and the uncertainty of the derived local discharge values. The derived runoff data proved to be useful information for the model calibration. Further analysis, examining the water balance and its components as well as snow cover, showed satisfactory simulation results. In conclusion, a unique runoff dataset for a small scale high-alpine catchment has been created to establish a hydrological flow prediction model which in a further step can be used for improved and sustainable hydropower management.

关键词： High alpine catchments Rainfall-runoff modelling Hydropower Ungauged basins

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Reliability of the Brownish-flanked Bush Warbler's soft song in male-male conflict

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Chinese Birds 2015年第2期6卷 107-112页

作者： Canwei Xia Boye Liu Daiping Wang Huw Lloyd Yanyun Zhang Ministry of Education Key Laboratory for Biodiversity and Ecological Engineering College of Life Sciences Beijing Normal University division of Biology and Conservation ecology School of Science and the Environment Manchester Metropolitan University

Background: Soft song is a low-amplitude song produced by many birds. Recent studies have confirmed that soft song is an aggressive signal. For example, the Brownish-flanked Bush Warblers Cettia fortipes use soft song in male-male conflicts, particularly prior to attacks. Although stable signaling systems require that signals be honest on average,models predict that cheating is an acceptable strategy for some individuals or in some ***: This study aimed to test the reliability of soft song as an aggressive signal in the brownish-flanked bush warbler. We used mounted specimens accompanied by broadcast songs or soft songs to simulate a male attempting to invade an existing ***: We found the mounted specimen that coupled playback of soft songs suffered more and quicker attacks from the territory owner and that the relationship between soft song and subsequent attack in the territory owner was far from perfect. We observed territory owners that both over-signaled(i.e., produced soft song but did not attack) and under-signaled(i.e., attacked without producing soft song). Under-signaling territory owners were relatively more commonly than were over-signaling territory owners, particularly in simulated intrusion that coupled playback of soft song with a mount ***: We discuss the cost of producing soft song and the potential benefit of the unreliable use of soft song and propose a new hypothesis for under-signaling with soft song; i.e., under-signaling territory owners might benefit from taking the initiative in fights.

关键词： Aggressive signal Brownish-flanked Bush Warbler Cost Reliability Soft song

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A study of groundwater irrigation water quality in south-central Bangladesh: a geo-statistical model approach using GIS and multivariate statistics

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Acta Geochimica 2018年第2期37卷 193-214页

作者： M.Atikul Islam Md.Mostafizur Rahman Md.Bodrud-Doza Md.Iftakharul Muhib Mashura Shammi Anwar Zahid Yeasmin Akter Masaaki Kurasaki Department of Chemistry Hajee Mohammad Danesh Science and Technology University Department of Environmental Sciences Jahangirnagar University Graduate School of Environmental Science Hokkaido University Department of Environmental Pollution and Process Control Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Groundwater hydrology Bangladesh Water Development Board Department of Chemistry University of Chittagong

Southern Bangladesh＇s irrigation and drinking water is threatened by saline intrusion. This study aimed to establish an irrigation water quality index （IWQI） using a geostatistical model and multivariate indices in Gopalganj district, south-central Bangladesh. Groundwater samples were taken randomly （different depths） in two seasons （wet-monsoon and dry-monsoon）. Hydrochemical analysis revealed groundwater in this area was neutral to slightly alkaline and dominating cations were Na^＋, Mg^2＋, and Ca^2＋ along with major anions Cl^- and HCO3^-. Principal component analysis and Gibbs plot helped explain possible geochemical processes in the aquifer. The irrigation water evaluation indices showed： electrical conductivity （EC）〉750 μS/cm, moderate to extreme saline; sodium adsorption ratio （SAR）, excellent to doubtful; total hardness （TH）, moderate to very hard; residual sodium bicarbonate, safe to marginal; Kelly＇s ratio 〉1; soluble sodium percentage （SSP）, fair to poor; magnesium adsorption ratio, harmful for soil; and IWQI, moderate to suitable. In addition, the best fitted semivariogram for IWQI, EC, SAR, SSP, and TH confirmed that most parameters had strong spatial dependence and others had moderate to weak spatial dependence. This variation might be due to the different origin/sources of major contributing ions along with the influence of variable river flow and small anthropogenic contributions. Furthermore, the spatial distribution maps for IWQI, EC, SSP, and TH during both seasons confirmed the influence of salinity from the sea; low-flow in the major river system was the driving factor of overall groundwater quality in the study area. These findings may contribute to management of irrigation and/or drinking water in regions with similar groundwater problems.

关键词： Semivariogram Ordinary kriging model Salinity Irrigation water quality index GIS Hydrochemistry

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Intercomparison measurements from commonly used precipitation gauges in the Qilian Mountains

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Advances in Climate Change Research 2023年第3期14卷 394-405页

作者： Yan-Ni ZHAO Ren-Sheng CHEN Lei WANG Chun-Tan HAN Jian-Ping YANG Qilian Alpine ecology and hydrology Research Station Key Laboratory of Ecological Safety and Sustainable Development in Arid LandsNorthwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China College of Geography and Environment Shandong Normal UniversityJinan 250014China

Precipitation data is vital fundamental data for climate ***,obtaining precise gauge-measured precipitation in high-altitude mountains is challenging,and the precipitation obtained from various gauge types at the same station may *** understand the differences in precipitation observations among the three commonly used gauges in China(Chinese Standard Precipitation Gauges(CSPG),Total Rain weighing Sensor(TRwS),and Geonor T-200B(T200B))in high-altitude mountains and to recommend a stable and cost-effective weighing gauge,a precipitation intercomparison experiment was conducted at Hulu-1 station in the Qilian *** wind-induced error in measurement was corrected with the‘universal’transfer function recommended by the Word Meteorological *** comparison results,adjusted for systematic errors,showed that the rain,snow and mixed precipitation of CSPG and TRwS equipped with the same octagonal vertical double fence shields(CSPGDF and TRwSDF)and single-Alter shields(CSPG_(s)and TRwSs)were close,while the precipitation of Tretyakov-shielded T200B was notably higher than that of CSPG_(s)and *** average differences in annual and daily precipitation between CSPGDF and TRwSDF from 2017 to 2021 were 12.9 mm and 0.10 mm,*** daily precipitation difference between CSPG_(s)and TRwSs from April 2019–December 2021 was 0.10 mm,while the differences between T200Bs and CSPG_(s)and TRwSs was 0.28 mm and 0.38 mm,*** wind shield performance of Alter and Tretyakov was not much different at Hulu-1 site with low wind speed,thus the measurement principle of T200Bs was the primary cause of the high *** the corrected CSPGDF measurement as the standard,the dynamic loss of CSPG_(s)was 17.6%,while that of CSPGUn was 55.6%,indicating that the single-Alter shield could effectively reduce the impact of wind on precipitation *** the comparison results and the price difference of the instruments,it was r

关键词： Precipitation intercomparison experiment Chinese standard precipitation gauge Total rain weighing sensors Geonor T-200B weighing Gauge Qilian mountains

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Land cover classification from remote sensing images based on multi-scale fully convolutional network

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Geo-Spatial Information Science 2022年第2期25卷 278-294页

作者： Rui Li Shunyi Zheng Chenxi Duan Libo Wang Ce Zhang School of Remote Sensing and Information Engineering Wuhan UniversityWuhanChina Faculty of Geo-Information Science and Earth Observation(ITC) University of TwenteEnschedeThe Netherlands The State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhanChina Lancaster Environment Centre Lancaster UniversityLancasterUK UK Centre for ecology&hydrology LancasterUK

Although the Convolutional Neural Network(CNN)has shown great potential for land cover classification,the frequently used single-scale convolution kernel limits the scope of informa-tion ***,we propose a Multi-Scale Fully Convolutional Network(MSFCN)with a multi-scale convolutional kernel as well as a Channel Attention Block(CAB)and a Global Pooling Module(GPM)in this paper to exploit discriminative representations from two-dimensional(2D)satellite ***,to explore the ability of the proposed MSFCN for spatio-temporal images,we expand our MSFCN to three-dimension using three-dimensional(3D)CNN,capable of harnessing each land cover category’s time series interac-tion from the reshaped spatio-temporal remote sensing *** verify the effectiveness of the proposed MSFCN,we conduct experiments on two spatial datasets and two spatio-temporal *** proposed MSFCN achieves 60.366%on the WHDLD dataset and 75.127%on the GID dataset in terms of mIoU index while the figures for two spatio-temporal datasets are 87.753%and 77.156%.Extensive comparative experiments and abla-tion studies demonstrate the effectiveness of the proposed MSFCN.

关键词： Spatio-temporal remote sensing images Multi-Scale Fully Convolutional Network land cover classification

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Ecological footprint of Gansu Province,China between 1997 and 2002:changes and inducement

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Ecological Economy 2009年第2期5卷 187-194页

作者： Shang Haiyang Chen Kegong Xu Zhongmin Sam Garland-Renn Laboratory of watershed hydrology and ecology Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of Sciences Lanzhou 730000 P. R. China College of Geography and Environmental Science Northwest Normal University Lanzhou 730070 P. R. China

The calculation of Ecological Footprint （EF） on the basis of Input-Output model （I-O model） was advanced by Bicknell, and modified and improved hy Ferng who corrected the footprint＇s aggregation to each sectors. For the lack of sufficient teehnique to deal with the trade between the research areas and the rest of the world, it it necessary to improve this method. And a dynamic analysis of the change of footprint based on I-O model, which could explore the factor impacting the footprint using the ,special advantage of I-O model, ought to be put into practice. After introducing the new method in detail, we calculate and compare the EF and the change of Gansu Province in the northwest of China in 1997 and 2002. The result shows that there was an increase of EF in 2002 caused by final domestic demand. Further; the inerement in EF export was 2.0 × 10^5 ha and 1.6 × 10^6 ha in import. The out-of- region support dropped from 22.6% to 18. 6%. We introduce three factors causing the EF change based on the character of I-O model： the productivity of the resourve which is explained by the change of resource used to obtain one unit output in a sector, the improvement of the economics and the final demand. Finally, we find that the effects of the three factors on the EF change are not identical except the industry sectors and the change of factors in the agriculture and the industry sectors works notably.

关键词： Ecological footprint Input-Output model Inducement to change IhPAT

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