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Vulnerability Assessment of Climate Change on Sea Level Rise Impacts on Some Economic Sectors in Binh Dinh Province, Vietnam 被引量:1
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作者 Mai Kim Lien 《American Journal of Climate Change》 2019年第2期302-324,共23页
Assessing the vulnerability for some economic sectors of Binh Dinh province plays a very important role. The study has applied the vulnerability method according to Iyengar and Sudarshan to assess vulnerability for 03... Assessing the vulnerability for some economic sectors of Binh Dinh province plays a very important role. The study has applied the vulnerability method according to Iyengar and Sudarshan to assess vulnerability for 03 different sectors: 1) Agriculture, forestry and fisheries;2) Industry and construction and 3) Service. Calculation results of vulnerability classification for different sector groups according to the E, S, AC, and Vi indicators are used to develop a hierarchy of vulnerability classification for different sector groups. The calculation results indicate that only Phu My district has a high vulnerability index for agriculture, forestry and fisheries with the value of Vi?= 0.6;For the service sector, only Quy Nhon City has a high vulnerability index with the value of Vi?= 0.63. The vulnerability index calculated for sector groups for the remaining regions is low to moderate. The result of the vulnerability classification maps due to sea level rise will help planners and managers make plans, plans and solutions to mitigate risks caused by natural disasters. 展开更多
关键词 VULNERABILITY Sea Level RISE ECONOMIC SECTORS Binh Dinh PROVINCE
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Study of Aerosol Direct and Indirect Effects and Auto-conversion Processes over the West African Monsoon Region Using a Regional Climate Model
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作者 Zeinab SALAH Ahmed SHALABY +3 位作者 Allison L. STEINER Ashraf S. ZAKEY Ritesh GAUTAM Mohamed M. ABDEL WAHAB 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2018年第2期182-194,共13页
This study assesses the direct and indirect effects of natural and anthropogenic aerosols (e.g., black carbon and sulfate) over West and Central Africa during the West African monsoon (WAM) period (June-July-Aug... This study assesses the direct and indirect effects of natural and anthropogenic aerosols (e.g., black carbon and sulfate) over West and Central Africa during the West African monsoon (WAM) period (June-July-August). We investigate the impacts of aerosols on the amount of cloudiness, the influences on the precipitation efficiency of clouds, and the associated radiative forcing (direct and indirect). Our study includes the implementation of three new formulations of auto-conversion parameterization [namely, the Beheng (BH), Tripoli and Cotton (TC) and Liu and Daum (R6) schemes] in RegCM4.4.1, besides the default model's auto-conversion scheme (Kessler). Among the new schemes, BH reduces the precipitation wet bias by more than 50% over West Africa and achieves a bias reduction of around 25% over Central Africa. Results from detailed sensitivity experiments suggest a significant path forward in terms of addressing the long-standing issue of the characteristic wet bias in RegCM. In terms of aerosol-induced radiative forcing, the impact of the various schemes is found to vary considerably (ranging from -5 to -25 W m-2). 展开更多
关键词 aerosol cloud West African monsoon auto-conversion REGCM
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Evaluating the Impacts of Cloud Microphysical and Overlap Parameters on Simulated Clouds in Global Climate Models
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作者 Haibo WANG Hua ZHANG +3 位作者 Bing XIE Xianwen JING Jingyi HE Yi LIU 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2022年第12期2172-2187,I0023,I0024,共18页
The improvement of the accuracy of simulated cloud-related variables,such as the cloud fraction,in global climate models(GCMs)is still a challenging problem in climate modeling.In this study,the influence of cloud mic... The improvement of the accuracy of simulated cloud-related variables,such as the cloud fraction,in global climate models(GCMs)is still a challenging problem in climate modeling.In this study,the influence of cloud microphysics schemes(one-moment versus two-moment schemes)and cloud overlap methods(observation-based versus a fixed vertical decorrelation length)on the simulated cloud fraction was assessed in the BCC_AGCM2.0_CUACE/Aero.Compared with the fixed decorrelation length method,the observation-based approach produced a significantly improved cloud fraction both globally and for four representative regions.The utilization of a two-moment cloud microphysics scheme,on the other hand,notably improved the simulated cloud fraction compared with the one-moment scheme;specifically,the relative bias in the global mean total cloud fraction decreased by 42.9%–84.8%.Furthermore,the total cloud fraction bias decreased by 6.6%in the boreal winter(DJF)and 1.64%in the boreal summer(JJA).Cloud radiative forcing globally and in the four regions improved by 0.3%−1.2% and 0.2%−2.0%,respectively.Thus,our results showed that the interaction between clouds and climate through microphysical and radiation processes is a key contributor to simulation uncertainty. 展开更多
关键词 cloud fraction cloud microphysics scheme cloud radiative forcing vertical cloud overlap
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Effect of preprocessing on performances of machine learning-based mineral composition analysis on gas hydrate sediments,Ulleung Basin,East Sea 被引量:1
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作者 Hongkeun Jin Ju Young Park +3 位作者 Sun Young Park Byeong-Kook Son Baehyun Min Kyungbook Lee 《Petroleum Science》 2025年第1期151-162,共12页
Gas hydrate(GH)is an unconventional resource estimated at 1000-120,000 trillion m^(3)worldwide.Research on GH is ongoing to determine its geological and flow characteristics for commercial produc-tion.After two large-... Gas hydrate(GH)is an unconventional resource estimated at 1000-120,000 trillion m^(3)worldwide.Research on GH is ongoing to determine its geological and flow characteristics for commercial produc-tion.After two large-scale drilling expeditions to study the GH-bearing zone in the Ulleung Basin,the mineral composition of 488 sediment samples was analyzed using X-ray diffraction(XRD).Because the analysis is costly and dependent on experts,a machine learning model was developed to predict the mineral composition using XRD intensity profiles as input data.However,the model’s performance was limited because of improper preprocessing of the intensity profile.Because preprocessing was applied to each feature,the intensity trend was not preserved even though this factor is the most important when analyzing mineral composition.In this study,the profile was preprocessed for each sample using min-max scaling because relative intensity is critical for mineral analysis.For 49 test data among the 488 data,the convolutional neural network(CNN)model improved the average absolute error and coefficient of determination by 41%and 46%,respectively,than those of CNN model with feature-based pre-processing.This study confirms that combining preprocessing for each sample with CNN is the most efficient approach for analyzing XRD data.The developed model can be used for the compositional analysis of sediment samples from the Ulleung Basin and the Korea Plateau.In addition,the overall procedure can be applied to any XRD data of sediments worldwide. 展开更多
关键词 Sample-based preprocessing X-ray diffraction(XRD) Machine learning Mineral composition Gas hydrate(GH) Ulleung basin
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Assessment of Future Climate Change Scenario in Halaba District, Southern Ethiopia
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作者 Tesemash Abebe Leta Bekele Misrak Tamire Hessebo 《Atmospheric and Climate Sciences》 2022年第2期283-296,共14页
Climate change is one environmental threat that poses great challenges to the future development prospects of Ethiopia. The study used the statistically downscaled daily data in 30-years intervals from the second gene... Climate change is one environmental threat that poses great challenges to the future development prospects of Ethiopia. The study used the statistically downscaled daily data in 30-years intervals from the second generation of the Earth System Model (CanESM2) under two Representative Concentration Pathways (RCPs): RCP 4.5 and RCP 8.5 for three future time slices;near-term (2010-2039), mid-century (2040-2069) and end-century (2071-2099) were generated. The observed data of maximum and minimum temperature and precipitation are a good simulation with the modeled data during the calibration and validation periods using the correlation coefficient (R<sup>2</sup>), the Nash-Sutcliffe efficiency (NSE), and the Root Mean Square Error (RMSE). The projected annual minimum and maximum temperatures are expected to increase by 0.091°C, 0.517°C, and 0.73°C and 0.072°C, 0.245°C, and 0.358°C in the 2020s, 2050s, and 2080s under the intermediate scenario, respectively. Under RCP8.5, the annual minimum and maximum temperatures are expected to increase by 0.192°C, 0.409°C, and 0.708°C, 0.402°C, 4.352°C, and 8.750°C in the 2020s, 2050s, and 2080s, respectively. Besides, the precipitation is expected to increase under intermediate and high emission scenarios by 1.314%, 7.643%, and 12.239%, and 1.269%, 10.316% and 26.298% in the 2020s, 2050s, and 2080s, respectively. Temperature and precipitation are projected to increase in total amounts under all-time slices and emissions pathways. In both emission scenarios, the greatest changes in maximum temperature, minimum temperature, and precipitation are predicted by the end of the century. This implies climate smart actions in development policies and activities need to consider locally downscale expected climatic changes. 展开更多
关键词 Statistical Downscaling Model RCP Scenarios Climate Change
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A Year Marked by Extreme Precipitation and Floods:Weather and Climate Extremes in 2024 被引量:1
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作者 Wenxia ZHANG Tianjun ZHOU +17 位作者 Wanheng YE Tingyu ZHANG Lixia ZHANG Piotr WOLSKI James RISBEY Zhuo WANG Seung-Ki MIN Hamish RAMSAY Michael BRODY Alice GRIMM Robin CLARK Kangnian REN Jie JIANG Xiaolong CHEN Shenming FU Lan LI Shijie TANG Shuai HU 《Advances in Atmospheric Sciences》 2025年第6期1045-1063,共19页
This past year, 2024, is on track to be the warmest year, joining 2023 as the two hottest years on record. With the exceptional heat, weather and climate extremes were common across the world. In particular, 2024 has ... This past year, 2024, is on track to be the warmest year, joining 2023 as the two hottest years on record. With the exceptional heat, weather and climate extremes were common across the world. In particular, 2024 has seen a remarkable run of extreme precipitation events and resulting impacts. Here, we provide an overview of the most notable extreme events of the year, including extreme precipitation and floods, tropical cyclones, and droughts. The characteristics and impacts of these extreme events are summarized, followed by discussion on the physical drivers and the role of global warming.Finally, we also discuss the future prospects in extreme event studies, including impact-based perspectives, challenges in attribution of precipitation extremes, and the existing gap to minimize impacts from climate extremes. 展开更多
关键词 weather and climate extremes extreme precipitation tropical cyclones DROUGHTS
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Tackling Climate Challenges Head-on
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作者 SUN ZHEN 《China Today》 2025年第11期26-30,共5页
IN his video speech to the United Nations Climate Summit held in New York on September 24,Chinese President Xi Jinping announced China’s new Nationally Determined Contributions(NDC)—the efforts taken by each country... IN his video speech to the United Nations Climate Summit held in New York on September 24,Chinese President Xi Jinping announced China’s new Nationally Determined Contributions(NDC)—the efforts taken by each country to reduce their emissions and adapt to the impacts of climate change. 展开更多
关键词 reduce their emissions adapt impacts climate change United Nations Climate Summit nationally determined contributions ndc climate summit nationally determined contributions green development climate change
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Biochar as a Climate-Smart Agricultural Practice: Reducing Greenhouse Gas Emissions and Promoting Sustainable Farming
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作者 Muhammad Nazim Abdul Ghafoor +5 位作者 Abida Hussain Mehwish Tabassum Aamir Nawaz Muhammad Ahmad Murad Muhammad Muqarrab Ali 《Phyton-International Journal of Experimental Botany》 2025年第1期65-99,共35页
In recent years, the world has faced rising global temperatures, accumulative pollution, and energy crises, stimulating scientists worldwide to strive for eco-friendly and cost-effective solutions. Biochar has materia... In recent years, the world has faced rising global temperatures, accumulative pollution, and energy crises, stimulating scientists worldwide to strive for eco-friendly and cost-effective solutions. Biochar has materialized as a favorable tool for environmental remediation, indicating efficacy as an efficient sorbent substance for both inorganic and organic pollutants in environmental field. These unique properties exclude improved surface functionality, porous morphology, large specific surface area (SSA), cation exchange capacity (CEC), robust adsorption capabilities, environmental stability, and embedded micronutrients. Biochar exhibited potential characteristics for environmental oversight, greenhouse gas (GHG) emission reduction, and soil fertility improvement. This review explores the impact of fundamental factors such as retention time, pyrolysis temperature, gas flow rate, and reactor design on biochar yield and properties. Collected data revealed the various applications of biochar, ranging from waste management and construction materials to the adsorptive removal of hydrocarbon lubricants from aqueous media, contaminant immobilization, and carbon sequestration. It has played mostly a significant share in climate change mitigation and an important role in soil amendments. Biochar improves soil improvement by increasing water retention (10%–30%), carbon sequestration, soil surface functionality, and providing high surface area with chemical stability. The assessment also reports the prospects and contests associated with biochar application uses in various agriculture cropping ecosystems. Inclusive, this review highlights the multifaceted characteristics of biochar as an adjustable on top of a sustainable solution addressing greenhouse gas emission, carbon sequestration, and environmental stresses. However, further research is needed to understand its long-term impacts and optimal applications fully. 展开更多
关键词 AGRO-ECOLOGY BIOCHAR carbon storage greenhouse gas reduction sustainable agriculture
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Statistical properties of kinetic-scale magnetic holes in terrestrial space 被引量:2
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作者 ShuTao Yao ZongShun Yue +15 位作者 QuanQi Shi Alexander William Degeling HuiShan Fu AnMin Tian Hui Zhang Andrew Vu RuiLong Guo ZhongHua Yao Ji Liu Qiu-Gang Zong XuZhi Zhou JingHuan Li WenYa Li HongQiao Hu YangYang Liu WeiJie Sun 《Earth and Planetary Physics》 CSCD 2021年第1期63-72,共10页
Kinetic-scale magnetic holes(KSMHs)are structures characterized by a significant magnetic depression with a length scale on the order of the proton gyroradius.These structures have been investigated in recent studies ... Kinetic-scale magnetic holes(KSMHs)are structures characterized by a significant magnetic depression with a length scale on the order of the proton gyroradius.These structures have been investigated in recent studies in near-Earth space,and found to be closely related to energy conversion and particle acceleration,wave-particle interactions,magnetic reconnection,and turbulence at the kineticscale.However,there are still several major issues of the KSMHs that need further study—including(a)the source of these structures(locally generated in near-Earth space,or carried by the solar wind),(b)the environmental conditions leading to their generation,and(c)their spatio-temporal characteristics.In this study,KSMHs in near-Earth space are investigated statistically using data from the Magnetospheric Multiscale mission.Approximately 200,000 events were observed from September 2015 to March 2020.Occurrence rates of such structures in the solar wind,magnetosheath,and magnetotail were obtained.We find that KSMHs occur in the magnetosheath at rates far above their occurrence in the solar wind.This indicates that most of the structures are generated locally in the magnetosheath,rather than advected with the solar wind.Moreover,KSMHs occur in the downstream region of the quasi-parallel shock at rates significantly higher than in the downstream region of the quasi-perpendicular shock,indicating a relationship with the turbulent plasma environment.Close to the magnetopause,we find that the depths of KSMHs decrease as their temporal-scale increases.We also find that the spatial-scales of the KSMHs near the subsolar magnetosheath are smaller than those in the flanks.Furthermore,their global distribution shows a significant dawn-dusk asymmetry(duskside dominating)in the magnetotail. 展开更多
关键词 kinetic scale magnetic hole magnetic dip electron vortex turbulence
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Characterizations of organic compounds in diesel exhaust particulates 被引量:1
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作者 Jaehyun Lim Cheolsoo Lim +1 位作者 Sangkyun Kim Jihyung Hong 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2015年第8期171-183,共13页
To characterize how the speed and load of a medium-duty diesel engine affected the organic compounds in diesel particle matter(PM) below 1 μm, four driving conditions were examined. At all four driving conditions, ... To characterize how the speed and load of a medium-duty diesel engine affected the organic compounds in diesel particle matter(PM) below 1 μm, four driving conditions were examined. At all four driving conditions, concentration of identifiable organic compounds in PM ultrafine(34–94 nm) and accumulation(94–1000 nm) modes ranged from 2.9 to 5.7 μg/m3 and 9.5 to 16.4 μg/m3, respectively. As a function of driving conditions, the non-oxygencontaining organics exhibited a reversed concentration trend to the oxygen-containing organics. The identified organic compounds were classified into eleven classes: alkanes,alkenes, alkynes, aromatic hydrocarbons, carboxylic acids, esters, ketones, alcohols, ethers,nitrogen-containing compounds, and sulfur-containing compounds. At all driving conditions,alkane class consistently showed the highest concentration(8.3 to 18.0 μg/m3) followed by carboxylic acid, esters, ketones and alcohols. Twelve polycyclic aromatic hydrocarbons(PAHs)were identified with a total concentration ranging from 37.9 to 174.8 ng/m3. In addition, nine nitrogen-containing polycyclic aromatic compounds(NPACs) were identified with a total concentration ranging from 7.0 to 10.3 ng/m3. The most abundant PAH(phenanthrene)and NPACs(7,8-benzoquinoline and 3-nitrophenanthrene) comprise a similar molecular(3 aromatic-ring) structure under the highest engine speed and engine load. 展开更多
关键词 Diesel particle matter Organic compounds Polycyclic aromatic hydrocarbons Nitrogen-containing polycyclic aromatic compounds
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Reply to Comment by Lamy et al. on “Locating the source field lines of Jovian decametric radio emissions” 被引量:1
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作者 YuMing Wang RuoBing Zheng +3 位作者 XianZhe Jia ChuanBing Wang Shui Wang V.Krupar 《Earth and Planetary Physics》 CSCD 2022年第1期13-17,共5页
Locating the source of decametric(DAM)radio emissions is a key step in the use of remote radio observations to understand the Jovian magnetospheric dynamics and their interaction with the planet’s moons.Wang YM et al... Locating the source of decametric(DAM)radio emissions is a key step in the use of remote radio observations to understand the Jovian magnetospheric dynamics and their interaction with the planet’s moons.Wang YM et al.(2020)presented a method by which recorded arc-shaped DAM emissions in the radio dynamic spectra can be used to locate the source of a DAM.An Io-related DAM event on March 14,2014 was used to demonstrate the method.A key parameter in the method is whether the DAM is emitted in the northern or the southern hemisphere;the hemisphere of origin can be determined definitively from the polarization of the emission.Unfortunately,polarization information for the emission on March 14,2014 event was not recorded.Our analysis assumed the source to be in the northern hemisphere.Lamy et al.(2022)argue convincingly that the source was probably in the southern hemisphere.We appreciate the helpful contribution of Lamy et al.(2022)to this discussion and have updated our analysis,this time assuming that the DAM source was in the southern hemisphere.We also explore the sensitivity of our method to another parameter-the height at which the value of fce,max,which is the maximal electron cyclotron frequency reached along the active magnetic flux tube,is adopted.Finally,we introduce our recent statistical study of 68 DAM events,which lays a more solid basis for testing the reliability of our method,which we continue to suggest is a promising tool by which remote radio observations can be used to locate the emission source of Jovian DAMs. 展开更多
关键词 radio decametric emissions Jovian magnetosphere energetic electrons
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Locating the source field lines of Jovian decametric radio emissions 被引量:2
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作者 YuMing Wang XianZhe Jia +2 位作者 ChuanBing Wang Shui Wang Vratislav Krupar 《Earth and Planetary Physics》 CSCD 2020年第2期95-104,共10页
Decametric(DAM) radio emissions are one of the main windows through which one can reveal and understand the Jovian magnetospheric dynamics and its interaction with the moons. DAMs are generated by energetic electrons ... Decametric(DAM) radio emissions are one of the main windows through which one can reveal and understand the Jovian magnetospheric dynamics and its interaction with the moons. DAMs are generated by energetic electrons through cyclotron-maser instability. For Io(the most active moon) related DAMs, the energetic electrons are sourced from Io volcanic activities, and quickly trapped by neighboring Jovian magnetic field. To properly interpret the physical processes behind DAMs, it is important to precisely locate the source field lines from which DAMs are emitted. Following the work by Hess et al.(2008, 2010), we develop a method to locate the source region as well as the associated field lines for any given DAM emission recorded in a radio dynamic spectrum by, e.g.,Wind/WAVES or STEREO/WAVES. The field lines are calculated by the state-of-art analytical model, called JRM09(Connerney et al., 2018).By using this method, we may also derive the emission cone angle and the energy of associated electrons. If multiple radio instruments at different perspectives observe the same DAM event, the evolution of its source region and associated field lines is able to be revealed. We apply the method to an Io-DAM event, and find that the method is valid and reliable. Some physical processes behind the DAM event are also discussed. 展开更多
关键词 radio decametric emissions Jovian magnetosphere energetic electrons
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Morphometric analysis and watershed delineation of the Karnaphuli river basin:A comparative study using different DEMs in Chittagong,Bangladesh 被引量:1
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作者 Sujit Kumar Roy Md.Arif Chowdhury 《River》 2024年第4期426-437,共12页
The present study aimed to delineate a robust watershed boundary and extract its morphometric parameters in the Karnaphuli watershed,Bangladesh,using different digital elevation models(DEMs).Two DEMs,the shuttle radar... The present study aimed to delineate a robust watershed boundary and extract its morphometric parameters in the Karnaphuli watershed,Bangladesh,using different digital elevation models(DEMs).Two DEMs,the shuttle radar topographic mission(SRTM)and the terra advanced spaceborne thermal emission and reflection radiometer(ASTER),were employed to delineate watershed boundaries and evaluate various morphometric characteristics.Raster data such as fill sinks,flow direction,and flow accumulation were utilized to delineate the watershed.The morphometric analysis included the estimation of linear,areal,and relief parameters.The findings revealed a noticeable difference between the datasets;ASTER delineated a larger watershed area than SRTM.Regarding stream order,there were streams ranging from 1st to 6th order,encompassing numerous small,medium,and main channels of the river.Drainage density was calculated as 0.52 km/km^(2)for SRTM and 0.51 km/km^(2)for ASTER,both having a spatial resolution of 30m.The bifurcation ratio ranged from 1.94 for SRTM to 2.45 for ASTER,indicating varying degrees of structural disturbance influenced by geological factors.The form factor indicated an elongated shape of the study area.The overall dimensions of the streams and the watershed extent suggest moderate mean annual rainfall discharge.The watershed exhibited relatively high denudation rates,attributed to the basin relief.A low drainage density indicated the importance of infiltration processes.The findings of this study provide valuable insights into the spatial variability of watershed characteristics,highlighting the need for tailored management strategies for the Karnaphuli River.Implementing targeted conservation measures and watershed management practices based on these morphometric parameters can enhance water resource sustainability and ecological health in the region. 展开更多
关键词 ASTER DEM Drainage network Karnaphuli river Morphometric analysis SRTM Watershed
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Iterative static modeling of channelized reservoirs using history-matched facies probability data and rejection of training image
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作者 Kyungbook Lee Sungil Kim +2 位作者 Jonggeun Choe Baehyun Min Hyun Suk Lee 《Petroleum Science》 SCIE CAS CSCD 2019年第1期127-147,共21页
Most inverse reservoir modeling techniques require many forward simulations, and the posterior models cannot preserve geological features of prior models. This study proposes an iterative static modeling approach that... Most inverse reservoir modeling techniques require many forward simulations, and the posterior models cannot preserve geological features of prior models. This study proposes an iterative static modeling approach that utilizes dynamic data for rejecting an unsuitable training image(TI) among a set of TI candidates and for synthesizing history-matched pseudo-soft data. The proposed method is applied to two cases of channelized reservoirs, which have uncertainty in channel geometry such as direction, amplitude, and width. Distance-based clustering is applied to the initial models in total to select the qualified models efficiently. The mean of the qualified models is employed as a history-matched facies probability map in the next iteration of static models. Also, the most plausible TI is determined among TI candidates by rejecting other TIs during the iteration. The posterior models of the proposed method outperform updated models of ensemble Kalman filter(EnKF) and ensemble smoother(ES) because they describe the true facies connectivity with bimodal distribution and predict oil and water production with a reasonable range of uncertainty. In terms of simulation time, it requires 30 times of forward simulation in history matching, while the EnKF and ES need 9000 times and 200 times, respectively. 展开更多
关键词 History-matched facies probability map Training image rejection Iterative static modeling Channelized reservoirs Multiple-point statistics History matching
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Heating of multi-species upflowing ion beams observed by Cluster on March 28, 2001
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作者 FangBo Yu SuiYan Fu +9 位作者 WeiJie Sun XuZhi Zhou Lun Xie Han Liu Duo Zhao ShaoJie Zhao Li Li JingWen Zhang Tong Wu Ying Xiong 《Earth and Planetary Physics》 CSCD 2019年第3期204-211,共8页
Cluster satellites observed three successive outflowing ion beams on 28 March, 2001. It is generally accepted that these ion beams, composed of H^+, He^+, and O^+ ions, with three inverted-V structures in their energy... Cluster satellites observed three successive outflowing ion beams on 28 March, 2001. It is generally accepted that these ion beams, composed of H^+, He^+, and O^+ ions, with three inverted-V structures in their energy spectra, are produced by acceleration through U-shaped potential structures. By eliminating the background ion population and employing Maxwelling fitting, we find that ions coming from the center of the potential structure have higher temperature than those from the flanks. Higher temperature of O^+ and He+compared to that of H^+ indicates that heavy ions are preferentially heated; we further infer that the heating efficiencies of O^+ and He^+ ions differ between the center and edges of the U-shaped potential structures. Estimation based on pitch angle observations shows that heating may also occur at an altitude above the upper boundary of the auroral acceleration region(AAR), where these beams are generally thought to be formed. 展开更多
关键词 oxygen ion beams inverted-V structures U-SHAPED potential drop preferentially heated heavy ions HEATING above AAR
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SPARC Local Workshop on “WCRP Grand Challenges and Regional Climate Change”
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作者 Joowan KIM Seok-Woo SON +2 位作者 Hye-Jin KIM Baek-Min KIM Changhyun YOO 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2018年第6期624-627,共4页
1.Overview SPARC(Stratosphere-Troposphere Processes and their Role in Climate)is one of the core projects of the World Climate Research Program(WCRP),coordinating international efforts to address relevant issues i... 1.Overview SPARC(Stratosphere-Troposphere Processes and their Role in Climate)is one of the core projects of the World Climate Research Program(WCRP),coordinating international efforts to address relevant issues in climate and climate prediction via better understanding of the stratosphere-troposphere system. 展开更多
关键词 SPARC Local Workshop on WCRP Grand Challenges and Regional Climate Change QBO
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Fault Ride-Through(FRT)Behavior in VSC-HVDC as Key Enabler of Transmission Systems Using SCADA Viewer Software
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作者 Samuel Bimenyimana Chen Wang +9 位作者 Godwin Norense Osarumwense Asemota Aphrodis Nduwamungu Francis Mulolani Jean De Dieu Niyonteze Shilpi Bora Chun-Ling Ho Noel Hagumimana Theobald Habineza Waqar Bashir Yiyi Mo 《Energy Engineering》 EI 2022年第6期2369-2406,共38页
The world’s energy consumption and power generation demand will continue to rise.Furthermore,the bulk of the energy resources needed to satisfy the rising demand is far from the load centers.The aforementioned requir... The world’s energy consumption and power generation demand will continue to rise.Furthermore,the bulk of the energy resources needed to satisfy the rising demand is far from the load centers.The aforementioned requires long-distance transmission systems and one way to accomplish this is to use high voltage direct current(HVDC)transmission systems.The main technical issues for HVDC transmission systems are loss of synchronism,variation of quadrature currents,amplitude,the inability of station 1(rectifier),and station 2(inverter)to either inject,or absorb active,or reactive power in the network in any circumstances(before a fault occurs,during having a fault in network and after a fault cleared),and the variations of power transfer capabilities.Additionally,faults impact power quality such as voltage dips and power line outage time.This paper presents a method of overcoming the aforementioned technical issues using voltage-source converter(VSC)based HVDC transmission systems with SCADA VIEWER software and dynamic grid simulator.The benefits include having a higher capacity transmission system and proposed best method for control of active and reactive power transfer capabilities.Simulation results obtained using MATLAB validated the experimental results from SCADA Viewer software.The results indicate that the station’s rectifier or inverter can either inject or absorb either active power or reactive power in any circumstance.Also,the reverse power flow under different modes of operation can ride through faults.At a 100.0%power transfer rate,the rectifier injected 775.0 W into the network.At a 0.0%power transfer rate,the rectifier injected 164.0 W into the network.At a-100.0%rated power,the rectifier injected 1264.0 W into the network and direction was also changed. 展开更多
关键词 Fault ride through capability dynamic grid fault simulator asymmetric components negative sequence control
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Profit Analysis by Soil Carbon Sequestration with Different Composts and Cooperated with Biochar during Corn (Zea mays) Cultivation Periods in Sandy Loam Soil
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作者 Joung Du Shin Yong-Su Choi Jae-Hoon Shin 《Journal of Agricultural Chemistry and Environment》 2016年第3期107-112,共7页
Despite the ability of biochar to enhance soil fertility and to sequester soil carbon, its potential reduction of green house gas emissions and profit analysis with different organic composts and cooperated with bioch... Despite the ability of biochar to enhance soil fertility and to sequester soil carbon, its potential reduction of green house gas emissions and profit analysis with different organic composts and cooperated with biochar for crop cultivation have been a few evaluated. This study was conducted to estimate their greenhouse gas emission reduction and profit analysis by soil carbon sequestration with different organic composts and cooperated with biochar application during corn cultivation periods. For the experiment, the treatments were consisted of aerobic digestate of swine wastes (AD), pig compost as the control (PC), cow compost (CC) and pig compost cooperated with 1% biochar (PC + 1% biochar). The soil texture used in this study was sandy loam, and application rates of chemical fertilizer were 190-39-221 kg·ha<sup>-1</sup> (N-P<sub>2</sub>O<sub>5</sub>-K<sub>2</sub>O) as recommended amount after soil test. The soil samples were periodically taken at every 15 day intervals during the experimental periods. It was observed that soil carbon sequestration by AD, CC and PC + 1% biochar application was estimated to be 429 kg·ha<sup>-1</sup>, 2366 kg·ha<sup>-1</sup>, and 3978 kg·ha<sup>-1</sup>, and their CO<sub>2</sub>-e emission reductions were estimated to be 0.16 tones for AD, 0.87 tones for CC, and 14.58 tones for PC + 1% biochar per hectar for corn cultivation periods. Their profits were estimated at $14.58 for lowest and $451.90 for highest. In Korea Climate Exchange, it was estimated to be $115.20 per hectar of corn cultivation with PC + 1% biochar. So, the price of CO<sub>2</sub> per hectar for corn cultivation with PC + 1% biochar was high at 16.8 times relative to cow compost treatment only. For the plant growth response, it was observed that plant height and fresh ear yield were not significantly different among the treatments. Therefore, these experimental results might be fundamental data for assuming a carbon trading mechanism exists for biochar soil application in agricultural practices. 展开更多
关键词 BIOCHAR Greenhouse Gas Emission Mitigation Soil Carbon Sequestration COMPOST
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Application of the AERMOD Model to Evaluate the Health Benefits Due to Air Pollution from the Public Transport Sector in Ha Noi, Viet Nam
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作者 Tran Do Bao Trung Doan Quang Tri 《Journal of Geoscience and Environment Protection》 2022年第3期13-33,共21页
Fine particulate matter (PM<sub>2.5</sub>) mainly originates from combustion emissions on-road transportation. Exposure to PM<sub>2.5</sub> could be considered one of the primary causes of dise... Fine particulate matter (PM<sub>2.5</sub>) mainly originates from combustion emissions on-road transportation. Exposure to PM<sub>2.5</sub> could be considered one of the primary causes of diseases such as heart attack, stroke, lung cancer, and chronic respiratory, which made it one of the most important co-benefits when evaluating the impact of GHG mitigation measures. This study quantifies the co-benefit of Ha Noi’s modal shift from private to public means of transport, which are reduced air pollution and extended life expectancy, combining AERMOD model and benefit transfer method. Analytical results show that shifting from motorbike to electric train could be the most beneficial option in term of health co-benefit, compared to the usage of standard buses and BRTs. 展开更多
关键词 AERMOD Model Air Pollution Health Co-Benefit Ha Noi
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Optimizing the transplanting window for higher productivity of short and medium duration rice cultivars in Punjab,India using CERES-Rice model
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作者 Anupama Aryal Prabhjyot-Kaur +1 位作者 Sandeep Singh Sandhu Shivani Kothiyal 《Circular Agricultural Systems》 2024年第1期85-95,共11页
The CERES-Rice(V4.7.5)model was used to identify the optimum transplanting window for higher productivity of rice in Indian Punjab.The model was first sensitized for 11 genetic coefficients and then these values were ... The CERES-Rice(V4.7.5)model was used to identify the optimum transplanting window for higher productivity of rice in Indian Punjab.The model was first sensitized for 11 genetic coefficients and then these values were used for calibrating and validating the model for rice cultivars.The Normalized Root Mean Square Error was in excellent range(<10%)for all the parameters—the coefficient of determination(R2)for CVS.PR126 and PR127 for days taken to anthesis and maturity were 0.94 and 0.89−0.96,respectively while grain yield and LAI(leaf area index)were 0.89−0.98 and 0.87−0.89,respectively.The optimum transplanting window of 24−30 June for PR126 and 20−26 June for PR127 simulated the grain yield/LAI ranging from 8,425−8,473 kg·ha^(−1)/4.23−4.24 for PR126 and 8,298−8,356 kg·ha^(−1)/4.20−4.21 for PR127.The early transplantation of rice cultivars on 7th June resulted in the lowest yield/LAI of 6,702 kg·ha^(−1)/3.8 for PR126 and 6,865 kg·ha^(−1)/3.9 for PR127.The deviation for the grain yield and HI(harvest index)of PR126 was between−14.2%to+8.2%and−15.1%to+10.5%,respectively,and of PR127 varied between−11.2%to+8.1%and−14.2%to+10.6%,respectively.The decline in the yield/HI from the average was observed during early transplantation in 2^(nd)week of June(before the 15^(th)of June for PR126 and the 13^(th)of June for PR127)as well as late transplantation in the 1st week of July(after 11^(th)July for PR126 and 6^(th)July for PR127)for rice cultivars.The negative effect on yield and HI of both varieties during early and late transplantation could be due to unfavorable climatic conditions. 展开更多
关键词 CULTIVAR PUNJAB optimum
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