期刊文献+
共找到26篇文章
< 1 2 >
每页显示 20 50 100
Uncertainty analysis for the calculation of marine environmental design parameters in the South China Sea
1
作者 Guilin LIU Xinsheng ZHOU +3 位作者 Yi KOU Fang WU Daniel ZHAO Yu XU 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2023年第2期427-443,共17页
The calculation results of marine environmental design parameters obtained from different data sampling methods,model distributions,and parameter estimation methods often vary greatly.To better analyze the uncertainti... The calculation results of marine environmental design parameters obtained from different data sampling methods,model distributions,and parameter estimation methods often vary greatly.To better analyze the uncertainties in the calculation of marine environmental design parameters,a general model uncertainty assessment method is necessary.We proposed a new multivariate model uncertainty assessment method for the calculation of marine environmental design parameters.The method divides the overall model uncertainty into two categories:aleatory uncertainty and epistemic uncertainty.The aleatory uncertainty of the model is obtained by analyzing the influence of the number and the dispersion degree of samples on the information entropy of the model.The epistemic uncertainty of the model is calculated using the information entropy of the model itself and the prediction error.The advantages of this method are that it does not require many-year-observation data for the marine environmental elements,and the method can be used to analyze any specific factors that cause model uncertainty.Results show that by applying the method to the South China Sea,the aleatory uncertainty of the model increases with the number of samples and then stabilizes.A positive correlation was revealed between the dispersion of the samples and the aleatory uncertainty of the model.Both the distribution of the model and the parameter estimation results of the model have significant effects on the epistemic uncertainty of the model.When the goodness-of-fit of the model is relatively close,the best model can be selected according to the criterion of the lowest overall uncertainty of the models,which can both ensure a better model fit and avoid too much uncertainty in the model calculation results.The presented multivariate model uncertainty assessment method provides a criterion to measure the advantages and disadvantages of the marine environmental design parameter calculation model from the aspect of uncertainty,which is of great significance to analyze the uncertainties in the calculation of marine environmental design parameters and improve the accuracy of the calculation results. 展开更多
关键词 South China Sea marine environmental design parameters model uncertainty information entropy Monte Carlo method
下载PDF
Detecting patterns of climate change in long-term forecasts of marine environmental parameters
2
作者 Gianpaolo Coro Pasquale Pagano Anton Ellenbroek 《International Journal of Digital Earth》 SCIE 2020年第5期567-585,共19页
Forecasting environmental parameters in the distant future requires complex modelling and large computational resources.Due to the sensitivity and complexity of forecast models,long-term parameter forecasts(e.g.up to ... Forecasting environmental parameters in the distant future requires complex modelling and large computational resources.Due to the sensitivity and complexity of forecast models,long-term parameter forecasts(e.g.up to 2100)are uncommon and only produced by a few organisations,in heterogeneous formats and based on different assumptions of greenhouse gases emissions.However,data mining techniques can be used to coerce the data to a uniform time and spatial representation,which facilitates their use in many applications.In this paper,streams of big data coming from AquaMaps and NASA collections of 126 long-term forecasts of nine types of environmental parameters are processed through a cloud computing platform in order to(i)standardise and harmonise the data representations,(ii)produce intermediate scenarios and new informative parameters,and(iii)align all sets on a common time and spatial resolution.Time series crosscorrelation applied to these aligned datasets reveals patterns of climate change and similarities between parameter trends in 10 marine areas.Our results highlight that(i)the Mediterranean Sea may have a standalone‘response’to climate change with respect to other areas,(ii)the Poles are most representative of global forecasted change,and(iii)the trends are generally alarming for most oceans. 展开更多
关键词 Climate change environmental parameters forecasting environmental parameters time series ecological modelling species distribution modelling AquaMaps NASA Earth Exchange
原文传递
Effects of particle composition and environmental parameters on catalytic hydrodechlorination of trichloroethylene by nanoscale bimetallic Ni-Fe 被引量:9
3
作者 Jianjun Wei Yajing Qian +5 位作者 Wenjuan Liu Lutao Wang Yijie Ge Jianghao Zhang Jiang Yu Xingmao Ma 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2014年第5期1162-1170,共9页
Catalytic nickel was successfully incorporated into nanoscale iron to enhance its dechlorination efficiency for trichloroethylene (TCE), one of the most commonly detected chlorinated organic compounds in groundwater... Catalytic nickel was successfully incorporated into nanoscale iron to enhance its dechlorination efficiency for trichloroethylene (TCE), one of the most commonly detected chlorinated organic compounds in groundwater. Ethane was the predominant product. The greatest dechlorination efficiency was achieved at 22 molar percent of nickel. This nanoscale Ni-Fe is poorly ordered and inhomogeneous; iron dissolution occurred whereas nickel was relatively stable during the 24-hr reaction. The morphological characterization provided significant new insights on the mechanism of catalytic hydrodcchlorination by bimetallic nanoparticles. TCE degradation and ethane production rates were greatly affected by environmental parameters such as solution pH, temperature and common groundwater ions. Both rate constants decreased and then increased over the pH range of 6.5 to 8.0, with the minimum value occurring at pH 7.5. TCE degradation rate constant showed an increasing trend over the temperature range of 10 to 25℃. However, ethane production rate constant increased and then decreased over the range, with the maximum value occurring at 20℃, Most salts in the solution appeared to enhance the reaction in the first half hour but overall they displayed an inhibitory effect. Combined ions showed a similar effect as individual salts. 展开更多
关键词 nanoscale Ni-Fe TRICHLOROETHYLENE HYDRODECHLORINATION catalytic dechlorination COMPOSITION environmental parameters
原文传递
Environmental parameters assessment of a new diffuser for air cooling/heating system:Measurements and numerical validation
4
作者 Fabio Nardecchia Laura Pompei Fabio Bisegna 《Building Simulation》 SCIE EI CSCD 2022年第6期1111-1132,共22页
Air distribution of HVAC systems is the most popular type used in the building sector,having a relevant impact on indoor air quality and occupant wellness.Many types of research developed optimal solutions for the HVA... Air distribution of HVAC systems is the most popular type used in the building sector,having a relevant impact on indoor air quality and occupant wellness.Many types of research developed optimal solutions for the HVAC system’s design,focusing on specific components of the distribution system,on the airflow and geometry of ducts,on the size of ducts,on the shape and position of air diffusers.However,few works in literature proposed a globally experimental and simulation analysis of an air distribution system with a variable mass flaw rate.Along this line,the presented research investigates the potentialities of a new ceiling diffuser,installed in an exhibition room.This system provides a variable mass flow rate thanks to its configuration,providing adequate thermal comfort.A warm wall is chosen as the heating system.Several tests are carried out,six for cooling and two for heating with different volumetric air rates and supply air temperature of the diffusers.The combination of two methods,the measurement campaigns and the computational fluid dynamics(CFD)technique represent a suitable approach to examine the thermal indoor environment.In general,results show a strong capability of this diffuser to provide a uniform temperature and velocity field inside the room.Moreover,experimental and numerical data are significantly comparable with an average deviation of 1%for the velocity and lower 1%for the temperature,guaranteeing an optimal distribution of the understudy environmental parameters on the vertical and horizontal planes. 展开更多
关键词 environmental parameters CFD field measurements INDULINE HVAC systems thermal comfort
原文传递
Organizational Modes and Environmental Conditions of the Severe Convective Weathers Produced by the Mesoscale Convective Systems in South China 被引量:1
5
作者 张元春 鲁蓉 +1 位作者 孙建华 杨新林 《Journal of Tropical Meteorology》 SCIE 2023年第1期26-38,共13页
Composite radar reflectivity data during April-September 2011-2015 are used to investigate and classify storms in south China(18-27°N;105-120°E). The storms appear most frequently in May. They are either lin... Composite radar reflectivity data during April-September 2011-2015 are used to investigate and classify storms in south China(18-27°N;105-120°E). The storms appear most frequently in May. They are either linear;cellular or nonlinear systems, taking up 29.45%, 24.51% and 46.04%, respectively, in terms of morphology. Linear systems are subdivided into six morphologies: trailing stratiform precipitation(TS), bow echoes(BE), leading stratiform precipitation(LS), embedded line(EL), no stratiform precipitation(NS) and parallel stratiform precipitation(PS). The TS and NS modes have the highest frequencies but there are only small samples of LS(0.61%) and PS(0.79%) modes.Severe convective wind(≥17m s-1at surface level) accounts for the highest percentage(35%) of severe convective weather events produced by cellular systems including individual cells(IC) and clusters of cells(CC). Short-duration heavy rainfall(≥50 mm h-1) and severe convective wind are the most common severe weather associated with TS and BE modes. Comparison of environmental physical parameters shows that cellular convection systems tend to occur in the environment with favorable thermal condition, substantial unstable energy and low precipitable water from the surface to300 hPa(PWAT). However, the environmental conditions favoring the initiation of linear systems feature strong vertical wind shear, high PWAT, and intense convective inhibition. The environmental parameters favoring the initiation of nonlinear systems are between those of the other two types of morphology. 展开更多
关键词 storms composite reflectivity MORPHOLOGY severe convective weather environmental physical parameter
下载PDF
Effect of copper slag recovery on hydrometallurgical cut-off grades considering environmental aspects 被引量:2
6
作者 AFSHIN AKBARI ESMAEIL RAHIMI 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第4期798-807,共10页
Determining the hydrometallurgical cut-off grades specifies the destination of low grade materials and this is subjected to more benefits in mining. Copper production rate is considered as one of the fundamental issue... Determining the hydrometallurgical cut-off grades specifies the destination of low grade materials and this is subjected to more benefits in mining. Copper production rate is considered as one of the fundamental issues in hydrometallurgical cut-off grades determination. Slags are remarked as one of the main sources of copper. It is not only regarded as a waste but also identified as another resource extracting base metals. Slags are characterized by copper high grade. Thus, slag copper recovery can be led to different cut-off grades and net present value(NPV). The current research scrutinizes the effect of slag recovery by both flotation and hydrometallurgical methods on the hydrometallurgical cut-off grades. For this purpose, the optimum cut-off grade algorithms of hydrometallurgical methods are developed by considering associated environmental parameters, incomes and also the costs. Then, their optimum amounts are calculated with NPV maximization as an objective function. The results indicate that considering slag copper recovery in the hydrometallurgical cut-off grade algorithms reduces the environmental costs caused by slag dumping and leads to more NPV by 9%. 展开更多
关键词 HYDROMETALLURGY cut-off grades low grade materials WASTE floatation SLAG copper recovery environmental parameters slag dumping NPV maximization
下载PDF
The safety parameters monitoring system for the coal mine based on CAN bus communication and intelligent data acquisition 被引量:4
7
作者 Bin Guangfu Chu Wangwen +1 位作者 Balbir S. Dhillon He Wenbiao 《Engineering Sciences》 EI 2008年第4期92-96,共5页
In this paper,a monitoring and controlling system for the safety in production and environmental parameters of a small and medium-sized coal mine has been developed after analyzing the current domestic coal production... In this paper,a monitoring and controlling system for the safety in production and environmental parameters of a small and medium-sized coal mine has been developed after analyzing the current domestic coal production and security conditions. The client computer can convert the analog signal about the safety in production and environmental parameters detected from the monitoring terminal into digital signal,and then,send the signal to the coal mine safety monitoring centre. This information can be analyzed,judged,and diagnosed by the monitoring-management-controlling software for helping the manager and technical workers to control the actual underground production and security situations. The system has many advantages including high reliability,better performance of real-time monitoring,faster data communicating and good practicability,and it can effectively prevent the occurrence of safety incidents in coal mines. 展开更多
关键词 small and mediumsized coal mine safety CAN bus communication intelligent data acquisition production parameters monitoring environmental parameters monitoring
下载PDF
Soil CO2 Efflux Dynamics and Its Relationship with the Environmental Variables in a Sub-Tropical Mixed Forest
8
作者 Deepa Dhital Rabina Manandhar +1 位作者 Puruswattam Manandhar Sanu Raja Maharjan 《Open Journal of Forestry》 2022年第3期312-336,共25页
Soil CO<sub>2</sub> efflux is an ongoing process of respiration from soil;plant parts/ microbes below the ground to the atmosphere which is known for faster cycling of carbon sources. A large portion of ca... Soil CO<sub>2</sub> efflux is an ongoing process of respiration from soil;plant parts/ microbes below the ground to the atmosphere which is known for faster cycling of carbon sources. A large portion of carbon sequestered and fixed by forests is returned to the atmosphere through soil CO<sub>2</sub> efflux and multiple controlling parameters mainly temperature, precipitation, and growth factors interact with the soil CO<sub>2</sub> efflux variation. This study assessed the soil CO<sub>2</sub> efflux every month for consecutive 2-years (August 2015 to July 2017) by using the closed chamber method to determine the role of ecological parameters that govern the soil CO<sub>2</sub> efflux and its temporal modification in a sub-tropical mixed forest of central region in Nepal. The results of this study manifested that soil CO<sub>2</sub> efflux accounted 63.2% (y = 31.96e<sup>0.128x</sup>), 71.3% (y = 44.77e<sup>0.123x</sup>) and 64.5% (y = 44.11e<sup>0.117x</sup>) variations in soil temperature with significantly (p < 0.05) exponential positive relation in the year 2015/2016, 2016/2017 and the two years when merged. And the temperature sensitivity value (Q<sub>10</sub>) of the soil CO<sub>2</sub> efflux was 3.6, 3.4, and 3.2, respectively. Soil water content also expressed significantly (p < 0.05) positive exponential effect on soil CO<sub>2</sub> efflux and accounted 62.0% (y = 138.3e<sup>0.057x</sup>), 46.1% (y = 88.42e<sup>0.052x</sup>) and 40.5% (y = 133.1e<sup>0.0447x</sup>) in its variability in different years and the merged years. Evident variations of soil CO<sub>2</sub> efflux, soil temperature, soil water content, and litter were observed in the forest seasonally and inter-annually. Two years mean total annual soil CO<sub>2</sub> efflux of the forest was estimated at 904.76 g C&#183;m<sup>-2</sup>&#183;y<sup>-1</sup>. The study revealed that sub-tropical forests could be more influenced by precipitation regimes in progressing warm climates i.e. vulnerable to climate change, illustrating the comprehensive dynamics of the representative forest carbon cycle in the tropical region. 展开更多
关键词 Soil CO2 Efflux environmental parameters Temperature Sensitivity (Q10) Sub-Tropical Forest Climate Change
下载PDF
Environmental Deterioration of the Tecomate Coastal Lagoon, in the Guerrero State, Mexico
9
作者 Salvador Villerías-Salinas Juan Violante-González +1 位作者 Neftalí García-Castro Lorena Alonzo-Guzmán 《International Journal of Geosciences》 2016年第1期1-10,共10页
An exhaustive field study was undertaken between November 2011 and August 2012, with the aim to know the causes of the environmental deterioration of the Tecomate Lagoon, in the Guerrero state, Mexico. Data of tempera... An exhaustive field study was undertaken between November 2011 and August 2012, with the aim to know the causes of the environmental deterioration of the Tecomate Lagoon, in the Guerrero state, Mexico. Data of temperature, dissolved oxygen, salinity parameters and depth of the lagoon were interpolated using the Kriging geostatistical method to generate a prediction surface. The lagoon registered a great variation in its saline concentration, which ranged from 8.0 to 65.0 ppt, with the lowest values in November 2011 and the highest at May 2012. The great variability in the salinity throughout the year contributed in significant form to the lagoon’s instability. An average water temperature of 32?C and dissolved oxygen levels of 4.49 to 7.44 mg/L were recorded. The low depth registered in the lagoon (mean = 1 m), is related to fluvial and marine processes, both of which modify depth through the transport of sediment to its interior. Currently, fishing is scarce, with the mangrove forest in some areas in a process of deterioration due to a lack of moisture. The lagoon system is undergoing a process of environmental deterioration, with an advanced ecological succession and non-aquatic vegetable species colonizing the area surrounding the lagoon. 展开更多
关键词 Tecomate Lagoon environmental parameters Habitat Deterioration Aquatic Ecosystem
下载PDF
Environmental Deterioration of the Tecomate Coastal Lagoon, in the Guerrero State, Mexico
10
作者 Salvador Villerías-Salinas Juan Violante-González +1 位作者 Neftalí García-Castro Lorena Alonzo-Guzmán 《International Journal of Geosciences》 2016年第1期1-10,共10页
An exhaustive field study was undertaken between November 2011 and August 2012, with the aim to know the causes of the environmental deterioration of the Tecomate Lagoon, in the Guerrero state, Mexico. Data of tempera... An exhaustive field study was undertaken between November 2011 and August 2012, with the aim to know the causes of the environmental deterioration of the Tecomate Lagoon, in the Guerrero state, Mexico. Data of temperature, dissolved oxygen, salinity parameters and depth of the lagoon were interpolated using the Kriging geostatistical method to generate a prediction surface. The lagoon registered a great variation in its saline concentration, which ranged from 8.0 to 65.0 ppt, with the lowest values in November 2011 and the highest at May 2012. The great variability in the salinity throughout the year contributed in significant form to the lagoon’s instability. An average water temperature of 32?C and dissolved oxygen levels of 4.49 to 7.44 mg/L were recorded. The low depth registered in the lagoon (mean = 1 m), is related to fluvial and marine processes, both of which modify depth through the transport of sediment to its interior. Currently, fishing is scarce, with the mangrove forest in some areas in a process of deterioration due to a lack of moisture. The lagoon system is undergoing a process of environmental deterioration, with an advanced ecological succession and non-aquatic vegetable species colonizing the area surrounding the lagoon. 展开更多
关键词 Tecomate Lagoon environmental parameters Habitat Deterioration Aquatic Ecosystem
下载PDF
SIMULATION-MEASUREMENT INVERSION OF ENVIRONMENT PARAMETERS DURING WELDING 被引量:1
11
作者 J. Tao D.Q. Li +1 位作者 C.L. Fan H.Y. Fang 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2005年第6期763-767,共5页
The manual selection of environment parameters during welding simulation will bring a significant error to the simulation result of welding temperature field. By a combination of finite element method (FEM) and infr... The manual selection of environment parameters during welding simulation will bring a significant error to the simulation result of welding temperature field. By a combination of finite element method (FEM) and infrared thermography, these environment parameters were inversed mathematically in place of previous manual selection. First, FEM model of the welding process was constructed, and the temperature field was computed with initial environment parameters. Then, a real welding process was conducted and the temperature field was measured by infrared thermography. Last, the simulation and measurement results were compared, and the environment parameters were adjusted continuously with the genetic algorithm ( GA ) until the simulation matched the measurement best. Parameters according to the best-matched simulation results were considered as the most appropriate parameters. 展开更多
关键词 environment parameters welding temperature field INVERSION
下载PDF
Identification of Health and Welfare Parameters for Rabbit Production and Definition of an Evaluation Score
12
作者 M. Cerioli R. Brivio +2 位作者 C. Tittarelli G. Grilli A. Lavazza 《Journal of Agricultural Science and Technology(A)》 2011年第4X期500-507,共8页
The knowledge on rabbit welfare may be improved by the use of correct tools for monitoring the different aspects of rabbit industrial farming. Therefore, the aim of this study was to define parameters related to healt... The knowledge on rabbit welfare may be improved by the use of correct tools for monitoring the different aspects of rabbit industrial farming. Therefore, the aim of this study was to define parameters related to health and welfare of animals in industrial farms with intensive husbandry. Health, management, environmental and productive parameters were firstly characterized and then a protocol to assess welfare of rabbits was define. The research was conducted on 8 industrial farms from 2004 to 2007 and around 30 inspections were done in each farm. At each visit, the health conditions were established by: (1) necropsy on animals of different productive category; (2) specific laboratory investigations based on the lesions observed; (3) checking the presence of parasites in environmental faecal samples; (4) bacteriological examination of vaginal, nasal and rectal swabs of rabbit of different age. The immune conditions and the efficacy of vaccinations were measured by determining anti-Myxomatosis and anti-Rabbit Haemorrhagic Disease antibodies using competitive ELISAs, and anti-Encephalitozoon cunicoli antibodies by immunocarbonassay. The environmental conditions were evaluated by measuring air temperature, relative humidity, ammonia concentration and bacterial/fungal count. Finally the productive parameters were also recorded and elaborated. All the entered values were then utilized for defining a score system to establish health and welfare conditions. 展开更多
关键词 RABBIT welfare monitoring health and zootechnical parameters environmental conditions score system.
下载PDF
Numerical Simulation of Icing on Nrel 5-MW Reference Offshore Wind Turbine Blades Under Different Icing Conditions 被引量:3
13
作者 CAO Hui-qing BAI Xu +2 位作者 MA Xian-dong YIN Qun YANG Xiang-yu 《China Ocean Engineering》 SCIE EI CSCD 2022年第5期767-780,共14页
Offshore wind energy resources are operational in cold regions,while offshore wind turbines will face the threat of icing.Therefore,it is necessary to study icing of offshore wind turbines under different icing condit... Offshore wind energy resources are operational in cold regions,while offshore wind turbines will face the threat of icing.Therefore,it is necessary to study icing of offshore wind turbines under different icing conditions.In this study,icing sensitivity of offshore wind turbine blades are performed using a combination of FLUENT and FENSAP-ICE software,and the effects of liquid water content(LWC),medium volume diameter(MVD),wind speed and air temperature on blade icing shape are analyzed by two types of ice,namely rime ice and glaze ice.The results show that the increase of LWC and MVD will increase the amount of ice that forms on the blade surface for either glaze ice or rime ice,and an increase of MVD will expand the adhesion surface between ice and blade.Before reaching the rated wind speed of 11.4 m/s,it does not directly affect the icing shape.However,after reaching the rated wind speed,the attack angle of the incoming flow decreases obviously,and the amount of ice increases markedly.When the ambient air temperature meets the icing conditions of glaze ice(i.e.,−5℃ to 0℃),the lower the temperature,the more glaze ice freezes,whereas air temperature has no impact on the icing of rime ice.Compared with onshore wind turbines,offshore wind turbines might face extreme meteorological conditions,and the wind speed has no impact on the amount of ice that forms on the blade surface for most wind speeds. 展开更多
关键词 environmental parameters cold regions offshore wind turbine RIME GLAZE numerical simulation
下载PDF
Benthic Habitat Quality Assessment Based on Biological Indices in Xiaoqing River Estuary and Its Adjacent Sea of Laizhou Bay,China 被引量:3
14
作者 LUO Xianxiang LIN Song +3 位作者 YANG Jianqiang SHEN Jiayu FAN Yuqing ZHANG Longjun 《Journal of Ocean University of China》 SCIE CAS CSCD 2017年第3期537-546,共10页
Based on the macrofauna data(2008-2011) in Xiaoqing River estuary and its adjacent sea, Laizhou Bay of Bohai Sea, China, the AZTI Marine Biotic Index(AMBI) and Multivariate AMBI(M-AMBI) were used for benthic habitat q... Based on the macrofauna data(2008-2011) in Xiaoqing River estuary and its adjacent sea, Laizhou Bay of Bohai Sea, China, the AZTI Marine Biotic Index(AMBI) and Multivariate AMBI(M-AMBI) were used for benthic habitat quality(BHQ) assessment. Results showed that BHQ presented an obvious trend of improvement along the direction of stream channel and river mouth, and in the coastal areas. AMBI and M-AMBI were significantly related to environmental pressure gradient data. Therefore, the two indices can well indicate BHQ in the studied area. However, there were significant differences between results of the two indices. In the cases of low taxa number and high abundance of single species, AMBI might overestimate BHQ. We thus adjusted its thresholds to solve this problem. And M-AMBI might overestimate BHQ when benthic assemblage was dominated by the opportunistic species. Then we could raise the weight of AMBI in the calculation of M-AMBI to handle the problem. 展开更多
关键词 Xiaoqing River estuary benthic habitat quality (BHQ) AMBI M-AMBI environmental parameters
下载PDF
Tidal water exchanges can shape the phytoplankton community structure and reduce the risk of harmful cyanobacterial blooms in a semi-closed lake 被引量:1
15
作者 Wenxu ZHENG Renhui LI +7 位作者 Wenli QIN Binbin CHEN Min WANG Wanchun GUAN Xiaoling ZHANG Qiao YANG Min ZHAO Zengling MA 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2022年第5期1868-1880,共13页
For estuaries,inland lakes play a vital role in the ecological balance under the impact of tide s.The effect of tides-induced water exchange on phytoplankton community in a semi-closed lake was studied and compared wi... For estuaries,inland lakes play a vital role in the ecological balance under the impact of tide s.The effect of tides-induced water exchange on phytoplankton community in a semi-closed lake was studied and compared with that of an adjacent closed lake in the Oujiang River mouth in Zhejiang,East China Sea,from June 29,2020 to June 14,2021.Results show that the dominant species,abundance,dominance,and diversity of the phytoplankton species between the two lakes were significantly different.In the closed lake,cyanobacteria were the dominant species during the study period.However.in the semi-closed lake,the diversification of the dominant species was greater,and some species of diatoms and green algae became dominant.The average phytoplankton abundance in the closed lake was 6 times of that in the semi-closed lake.The average dominance of cyanobacteria in the closed lake was 0.96,and those in the semi-closed lake and the Oujiang River were 0.51 and 0.22,respectively.Cyanobacterial blooms occurred throughout the study time in the closed lake but not in the semi-closed one.Furthermore,the species diversity richness of the phytoplankton in the semi-closed lake was higher than that of the closed one,and the phytoplankton community between the closed lake and semi-closed lake could be divided into distinctly different groups based on non-metic multidimensional scaling analysis(NMDS)and analysis of similarities(ANOSIM)analysis.The salinity of the water was significantly greater and the transparency significantly smaller in the semi-closed lake than those in the closed lake.Therefore,water exchange driven by local tidal movement increased salinity and decreased transparency of water,which consequently shaped the community structures of different phytoplankton and reduced the risk of a cyanobacterial bloom outbreak in the semi-closed lake. 展开更多
关键词 ESTUARY harmful cyanobacterial blooms phytoplankton community water exchange tidal movement environmental parameters
下载PDF
A Forest Growth Dynamic Indicator
16
作者 Vinicius Leal Thomaz Costa Andreia Silva 《Journal of Environmental Science and Engineering(A)》 2017年第2期68-84,共17页
The dynamics of forest growth are related to the succession stage, the quality of the environment and the degree of anthropism. The growth of a forest is given by the activity of live trees, mortality, and trees that ... The dynamics of forest growth are related to the succession stage, the quality of the environment and the degree of anthropism. The growth of a forest is given by the activity of live trees, mortality, and trees that are cut or recruited during the growing period. A way of representing the growth dynamics of a forest is by the Transition Matrix, with the divisibility of the population in states, with probabilities of movement from one state to another, over time. Forest dynamics studies are carried out by means of a continuous forest inventory, allowing the calculation of gains and losses in basal area, mortality rates and ingrowth. In this study, the measurements were performed with a 5-year interval, on 27 plots distributed in 12 sites. The methodology correlated parameters of the forest dynamics with canopy, soil, relief and hydrographic parameters. An indicator of forest growth dynamics was proposed and it was tested. It was confirmed that the density factor interferes in growth dynamics of the forest. 展开更多
关键词 Transition matrix INDEX environmental parameters.
下载PDF
Patella rustica Linnaeus, 1758 (Gastropoda, Patellogastropoda) Inhabiting Coast of Skikda (AIgerie)
17
作者 Razika Maatallah Djebar Abdallah Borhane 《Journal of Life Sciences》 2014年第1期65-77,共13页
The study was undergone on the distribution of abundance of Patella rustica Linnaeus, 1758, with the objective of evaluating of its abundance along the rocky shores of the coast and located sites with high density. A ... The study was undergone on the distribution of abundance of Patella rustica Linnaeus, 1758, with the objective of evaluating of its abundance along the rocky shores of the coast and located sites with high density. A total of twelve sampling sites were selected along the gulf of Skikda. Each station was sampled using quadrats of 25 cm^2. In the present study, two environmental parameters were measured "in situ" in the water column at each sampling station (water surface temperature, pH). Biotic communities of the rocky shores are considered to be generally controlled by physical factors such as temperature and desiccation. Therefore, three measurements were made for each abiotic parameter during this survey and mean values were used for statistical analysis. Consequently, the data of abundance (expressed in frequency) of species were calculated based on the distributed individuals along the quadrat. P. rustica is distributed mainly in the East more than in the West particularly from SI to S5. The condition index calculated at 12 stations revealed important seasonal variations, with the maximum during summer season highlighting three stations (S2, S11 and S 12). This index is also very important in S3 and S4. The factors of pollution at these points had not affected the abundance and index condition. 展开更多
关键词 ABUNDANCE index of condition environmental parameters Patella rustica.
下载PDF
Optimum Designing of Gas Distribution Networks of Ilam Province by Using GIS Network and Spatial Analysis
18
作者 Hosein Anvari Bakhtiar Feizizadeh Rasool Olyani Nejad 《Open Journal of Geology》 2016年第8期801-811,共11页
Undoubtedly, pipeline transport is considered as significant economical artery of country and national valuable resources, so it is necessary to use latest technologies, major standards and instructions and the best h... Undoubtedly, pipeline transport is considered as significant economical artery of country and national valuable resources, so it is necessary to use latest technologies, major standards and instructions and the best human resources in designing, operation and supervision in construction and also protection of it. Also, all authorities and involved of construction and operation of gas industries installation should observe safety criteria, health and environment and aware of them ever. In fact, in designing of these programs, in addition to technical and economical points, environmental characteristics should be considered in order to their construction has minimum damage to environment. On the other hand, common and traditional approaches of pipeline routing are based on using costly and time-consuming methods. In these methods, it is not easily to use all effective parameters in determining optimum way. According to capability of analysis of network spatial information systems in incorporation of spatial data, for using all effective parameters in routing, this environment is used, therefore weighted overlay analysis (Boleyn, index and fuzzy) and shortest path are modeled for finding optimum path of pipeline in GIS environment. 展开更多
关键词 Designing Optimum Path Hierarchical Analysis environmental parameters Geographical Information System
下载PDF
Intensive Radiosonde Measurements of Summertime Convection over the Inner Mongolia Grassland in 2014:Difference between Shallow Cumulus and Other Conditions 被引量:2
19
作者 Hongrong SHI Hongbin CHEN +4 位作者 Xiang'ao XIA Xuehua FAN Jinqiang ZHANG Jun LI Chao LING 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2017年第6期783-790,共8页
Using radiosonde measurements from 26 July to 30 July 2014 at Baiqi over the Inner Mongolia grassland of China, the vertical structure of shallow cumulus (SCu) clouds and associated environmental conditions were inv... Using radiosonde measurements from 26 July to 30 July 2014 at Baiqi over the Inner Mongolia grassland of China, the vertical structure of shallow cumulus (SCu) clouds and associated environmental conditions were investigated. The cloud base height and the cloud top height of SCu was 3.4 km and 5 km, respectively. The temperature of the SCu layer was less than 0℃. The horizontal advection of specific humidity was smaller than the vertical transport in the atmosphere below 5 km. Above 5 km, the thermodynamic structure of the atmosphere remained stable. At the interface of the cloud layer and free air atmosphere, there was obvious wind shear and a temperature inversion (-2.9~C). Comparisons of environmental parameters associated with cumulus congestus, rain and clear days, showed that the formation of SCu was characterized by a higher Bowen ratio (high sensible heat flux and low latent heat flux), which indicated intensive turbulence in the boundary layer. The formation of SCu was associated with the boundary layer height exceeding the lifting condensation level. The maintenance of SCu was likely associated with the lower convective available potential energy, weak wind shear, and weak subsidence of the synoptic system, which did not favor the dramatic vertical development of SCu and thereby the transformation of SCu to cumulus congestus. 展开更多
关键词 shallow cumulus sounding measurement environmental parameter Inner Mongolia grassland
下载PDF
Improvement of Theories and Methods in Geodetic Joint Inversion
20
作者 XU Caijun 《Geo-Spatial Information Science》 2003年第1期12-18,共7页
This paper first establishes the prior globe dynamical model by geophysics,which is a solid earth elastic deformation model.Then,the parameters of the globe dynamic model can be obtained by inverting the geodetic data... This paper first establishes the prior globe dynamical model by geophysics,which is a solid earth elastic deformation model.Then,the parameters of the globe dynamic model can be obtained by inverting the geodetic data.The inverse method can be used in seismology and geology,and to make earthquake prediction. 展开更多
关键词 joint inversion theory crustal movement medium parameter ocean environment parameter
下载PDF
上一页 1 2 下一页 到第
使用帮助 返回顶部