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从中国首台紫外-可见光高光谱卫星仪器反演得到的高空间分辨率臭氧廓线 被引量:1
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作者 Fei Zhao Cheng Liu +3 位作者 Qihou Hu Congzi Xia chengxin zhang Wenjing Su 《Engineering》 SCIE EI CAS CSCD 2024年第1期106-115,共10页
Understanding the vertical distribution of ozone is crucial when assessing both its horizontal and vertical transport,as well as when analyzing the physical and chemical properties of the atmosphere.One of the most ef... Understanding the vertical distribution of ozone is crucial when assessing both its horizontal and vertical transport,as well as when analyzing the physical and chemical properties of the atmosphere.One of the most effective ways to obtain high spatial resolution ozone profiles is through satellite observations.The Environmental Trace Gases Monitoring Instrument(EMI)deployed on the Gaofen-5 satellite is the first Chinese ultraviolet-visible hyperspectral spectrometer.However,retrieving ozone profiles using backscattered radiance values measured by the EMI is challenging due to unavailable measurement errors and a low signal-to-noise ratio.The algorithm developed for the Tropospheric Monitoring Instrument did not allow us to retrieve 87%of the EMI pixels.Therefore,we developed an algorithm specific to the characteristics of the EMI.The fitting residuals are smaller than 0.3%in most regions.The retrieved ozone profiles were in good agreement with ozonesonde data,with maximum mean biases of 20%at five latitude bands.By applying EMI averaging kernels to the ozonesonde profiles,the integrated stratospheric column ozone and tropospheric column ozone also showed excellent agreement with ozonesonde data,The lower layers(0-7.5 km)of the EMI ozone profiles reflected the seasonal variation in surface ozone derived from the China National Environmental Monitoring Center(CNEMC).However,the upper layers(9.7-16.7 km)of the ozone profiles show different trends,with the ozone peak occurring at an altitude of 9.7-16.7 km in March,2019.A stratospheric intrusion event in central China from August 11 to 15,2019,is captured using the EMI ozone profiles,potential vorticity data,and relative humidity data.The increase in the CNEMC ozone co ncentration showed that downward transport enhanced surface ozone pollution. 展开更多
关键词 Ozone profiles EMI Soft calibration Floor noise correction Stratospheric ozone intrusion
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A Novel Localized Meshless Method for Solving Transient Heat Conduction Problems in Complicated Domains
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作者 chengxin zhang Chao Wang +1 位作者 Shouhai Chen Fajie Wang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第6期2407-2424,共18页
This paper first attempts to solve the transient heat conduction problem by combining the recently proposed local knot method(LKM)with the dual reciprocity method(DRM).Firstly,the temporal derivative is discretized by... This paper first attempts to solve the transient heat conduction problem by combining the recently proposed local knot method(LKM)with the dual reciprocity method(DRM).Firstly,the temporal derivative is discretized by a finite difference scheme,and thus the governing equation of transient heat transfer is transformed into a non-homogeneous modified Helmholtz equation.Secondly,the solution of the non-homogeneous modified Helmholtz equation is decomposed into a particular solution and a homogeneous solution.And then,the DRM and LKM are used to solve the particular solution of the non-homogeneous equation and the homogeneous solution of the modified Helmholtz equation,respectively.The LKM is a recently proposed local radial basis function collocationmethod with themerits of being simple,accurate,and free ofmesh and integration.Compared with the traditional domain-type and boundary-type schemes,the present coupling algorithm could be treated as a really good alternative for the analysis of transient heat conduction on high-dimensional and complicated domains.Numerical experiments,including two-and three-dimensional heat transfer models,demonstrated the effectiveness and accuracy of the new methodology. 展开更多
关键词 Local knot method transient heat conduction dual reciprocity method meshless method
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Variability of PM_(2.5) and O_(3) concentrations and their driving forces over Chinese megacities during 2018-2020 被引量:2
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作者 Tianyi Xu chengxin zhang +1 位作者 Cheng Liu Qihou Hu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2023年第2期1-10,共10页
Recently,air pollution especially fine particulate matters(PM_(2.5))and ozone(O_(3))has become a severe issue in China.In this study,we first characterized the temporal trends of PM_(2.5) and O_(3) for Beijing,Guangzh... Recently,air pollution especially fine particulate matters(PM_(2.5))and ozone(O_(3))has become a severe issue in China.In this study,we first characterized the temporal trends of PM_(2.5) and O_(3) for Beijing,Guangzhou,Shanghai,andWuhan respectively during 2018-2020.The annual mean PM2.5 has decreased by 7.82%-33.92%,while O_(3) concentration showed insignificant variations by-6.77%-4.65%during 2018-2020.The generalized additive models(GAMs)were implemented to quantify the contribution of individual meteorological factors and their gas precursors on PM_(2.5) and O_(3).On a short-term perspective,GAMs modeling shows that the daily variability of PM_(2.5) concentration is largely related to the variation of precursor gases(R=0.67-0.90),while meteorological conditions mainly affect the daily variability of O_(3) concentration(R=0.65-0.80)during 2018-2020.The impact of COVID-19 lockdown on PM_(2.5) and O_(3) concentrations were also quantified by using GAMs.During the 2020 lockdown,PM_(2.5) decreased significantly for these megacities,yet the ozone concentration showed an increasing trend compared to 2019.The GAMs analysis indicated that the contribution of precursor gases to PM_(2.5) and O_(3) changes is 3-8 times higher than that of meteorological factors.In general,GAMsmodeling on air quality is helpful to the understanding and control of PM2.5 and O3 pollution in China. 展开更多
关键词 Air pollution PM_(2.5)and O_(3)trends METEOROLOGY COVID-19 lockdown
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基于国产卫星遥感的北京冬奥会空气质量监测和追因 被引量:1
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作者 吴洁 张成歆 +10 位作者 胡启后 苏文静 刘思含 游代安 滕佳华 赵少华 马鹏飞 王中挺 周春艳 申文明 刘诚 《科学通报》 EI CAS CSCD 北大核心 2023年第20期2665-2677,共13页
2021年9月,高光谱观测卫星高分五号02星成功发射,有效提升了我国大气环境遥感监测的综合应用水平,为空气质量保障提供了自主可控的遥感数据支撑.在2022年1~3月北京-张家口冬奥会期间,我们近实时反演获取了高分五号02星污染气体监测产品... 2021年9月,高光谱观测卫星高分五号02星成功发射,有效提升了我国大气环境遥感监测的综合应用水平,为空气质量保障提供了自主可控的遥感数据支撑.在2022年1~3月北京-张家口冬奥会期间,我们近实时反演获取了高分五号02星污染气体监测产品,并通过生态环境部卫星环境应用中心为冬奥会提供监测分析日报.本文分析了冬奥会期间北京及周边重点城市的对流层二氧化氮(NO_(2))时空分布特征,探讨了气象条件和人为排放控制措施对冬奥会期间NO_(2)浓度的影响.国产卫星反演结果表明,冬奥会期间华北地区平均对流层NO_(2)柱浓度稳定在3.75×10^(15)molecules/cm^(2)以下,低于会前和会后.不同城市在冬奥会期间NO_(2)柱浓度下降幅度在53.1%~70.1%之间,说明临时管控政策对空气质量改善效果显著,但不同城市的减排实施有差异.这与国控站点近地面NO_(2)监测结果具有较好的一致性.冬奥会期间出现两天NO_(2)浓度高值,主要受不利风场条件影响.本文还通过建立广义相加模型来区分和量化人为减排等非气象因素与气象因素对于对流层NO_(2)浓度变化的贡献,保定、北京、天津和太原在冬奥会期间的NO_(2)浓度分别下降了48.2%、67.5%、48.8%和72.8%,其中人为排放和气象因素分别贡献了41.8%、32.0%、30.0%、42.8%和6.4%、35.6%、18.8%、30.1%.总体上,气象因素影响要弱于排放临时管控措施.该研究首次利用国产卫星为冬奥会提供污染气体监测和溯源分析,有力支撑了我国大气环境遥感监测的应用. 展开更多
关键词 卫星遥感 氮氧化物 空气质量监测 大气污染成因
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Satellite UV-Vis spectroscopy:implications for air quality trends and their driving forces in China during 2005-2017 被引量:20
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作者 chengxin zhang Cheng Liu +6 位作者 Qihou Hu Zhaonan Cai Wenjing Su Congzi Xia Yizhi Zhu Siwen Wang Jianguo Liu 《Light(Science & Applications)》 SCIE EI CAS CSCD 2019年第1期246-257,共12页
Abundances of a range of air pollutants can be inferred from satellite UV-Vis spectroscopy measurements by using the unique absorption signatures of gas species.Here,we implemented several spectral fitting methods to ... Abundances of a range of air pollutants can be inferred from satellite UV-Vis spectroscopy measurements by using the unique absorption signatures of gas species.Here,we implemented several spectral fitting methods to retrieve tropospheric NO_(2),SO_(2),and HCHO from the ozone monitoring instrument(OMI),with radiative simulations providing necessary information on the interactions of scattered solar light within the atmosphere.We analyzed the spatial distribution and temporal trends of satellite-observed air pollutants over eastern China during 2005-2017,especially in heavily polluted regions.We found significant decreasing trends in NO_(2) and SO_(2) since 2011 over most regions,despite varying temporal features and turning points.In contrast,an overall increasing trend was identified for tropospheric HCHO over these regions in recent years.Furthermore,generalized additive models were implemented to understand the driving forces of air quality trends in China and assess the effectiveness of emission controls.Our results indicated that although meteorological parameters,such as wind,water vapor,solar radiation and temperature,mainly dominated the day-to-day and seasonal fluctuations in air pollutants,anthropogenic emissions played a unique role in the long-term variation in the ambient concentrations of NO_(2),SO_(2),and HCHO in the past 13 years.Generally,recent declines in NO_(2) and SO_(2) could be attributed to emission reductions due to effective air quality policies,and the opposite trends in HCHO may urge the need to control anthropogenic volatile organic compound(VOC)emissions. 展开更多
关键词 driving FORCES spectroscopy
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First observation of tropospheric nitrogen dioxide from the Environmental Trace Gases Monitoring Instrument onboard the GaoFen-5 satellite 被引量:16
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作者 chengxin zhang Cheng Liu +8 位作者 Ka Lok Chan Qihou Hu Haoran Liu Bo Li Chengzhi Xing Wei Tan Haijin Zhou Fuqi Si Jianguo Liu 《Light(Science & Applications)》 SCIE EI CAS CSCD 2020年第1期1389-1397,共9页
The Environmental Trace Gases Monitoring Instrument(EMI)is the first Chinese satellite-borne UV–Vis spectrometer aiming to measure the distribution of atmospheric trace gases on a global scale.The EMI instrument onbo... The Environmental Trace Gases Monitoring Instrument(EMI)is the first Chinese satellite-borne UV–Vis spectrometer aiming to measure the distribution of atmospheric trace gases on a global scale.The EMI instrument onboard the GaoFen-5 satellite was launched on 9 May 2018.In this paper,we present the tropospheric nitrogen dioxide(NO2)vertical column density(VCD)retrieval algorithm dedicated to EMI measurement.We report the first successful retrieval of tropospheric NO_(2) VCD from the EMI instrument.Our retrieval improved the original EMI NO_(2) prototype algorithm by modifying the settings of the spectral fit and air mass factor calculations to account for the on-orbit instrumental performance changes.The retrieved EMI NO_(2) VCDs generally show good spatiotemporal agreement with the satellite-borne Ozone Monitoring Instrument and TROPOspheric Monitoring Instrument(correlation coefficient R of ~0.9,bias<50%).A comparison with ground-based MAX-DOAS(Multi-Axis Differential Optical Absorption Spectroscopy)observations also shows good correlation with an R of 0.82.The results indicate that the EMI NO_(2) retrieval algorithm derives reliable and precise results,and this algorithm can feasibly produce stable operational products that can contribute to global air pollution monitoring. 展开更多
关键词 measurement dioxide SATELLITE
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First sulfur dioxide observations from the environmental trace gases monitoring instrument(EMI)onboard the GeoFen-5 satellite 被引量:6
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作者 Congzi Xia Cheng Liu +4 位作者 Zhaonan Cai Fei Zhao Wenjing Su chengxin zhang Yi Liu 《Science Bulletin》 SCIE EI CSCD 2021年第10期969-973,M0003,共6页
Previous studies reported a significant overestimation of the Sentinel-5 Precursor(S-5P)official operational SO_(2) product in global SO_(2) emissions[1],[2].As such,China successfully launched the GaoFen-5 satellite ... Previous studies reported a significant overestimation of the Sentinel-5 Precursor(S-5P)official operational SO_(2) product in global SO_(2) emissions[1],[2].As such,China successfully launched the GaoFen-5 satellite into the sun-synchronous polar orbit on May 9,2018[3]. 展开更多
关键词 太阳光谱 二氧化硫 时空一致性 环境遥感 光谱质量 地面观测 痕量气体 对流层大气
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First Chinese ultraviolet-visible hyperspectral satellite instrument implicating global air quality during the COVID-19 pandemic in early 2020 被引量:2
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作者 Cheng Liu Qihou Hu +6 位作者 chengxin zhang Congzi Xia Hao Yin Wenjing Su Xiaohan Wang Yizhou Xu Zhiguo zhang 《Light(Science & Applications)》 SCIE EI CAS CSCD 2022年第2期242-253,共12页
In response to the COVID-19 pandemic,governments worldwide imposed lockdown measures in early 2020,resulting in notable reductions in air pollutant emissions.The changes in air quality during the pandemic have been in... In response to the COVID-19 pandemic,governments worldwide imposed lockdown measures in early 2020,resulting in notable reductions in air pollutant emissions.The changes in air quality during the pandemic have been investigated in numerous studies via satellite observations.Nevertheless,no relevant research has been gathered using Chinese satellite instruments,because the poor spectral quality makes it extremely difficult to retrieve data from the spectra of the Environmental Trace Gases Monitoring Instrument(EMI),the first Chinese satellite-based ultraviolet–visible spectrometer monitoring air pollutants.However,through a series of remote sensing algorithm optimizations from spectral calibration to retrieval,we successfully retrieved global gaseous pollutants,such as nitrogen dioxide(NO2),sulfur dioxide(SO2),and formaldehyde(HCHO),from EMI during the pandemic.The abrupt drop in NO2 successfully captured the time for each city when effective measures were implemented to prevent the spread of the pandemic,for example,in January 2020 in Chinese cities,February in Seoul,and March in Tokyo and various cities across Europe and America.Furthermore,significant decreases in HCHO in Wuhan,Shanghai,Guangzhou,and Seoul indicated that the majority of volatile organic compounds(VOCs)emissions were anthropogenic.Contrastingly,the lack of evident reduction in Beijing and New Delhi suggested dominant natural sources of VOCs.By comparing the relative variation of NO2 to gross domestic product(GDP),we found that the COVID-19 pandemic had more influence on the secondary industry in China,while on the primary and tertiary industries in Korea and the countries across Europe and America. 展开更多
关键词 ULTRAVIOLET VISIBLE dioxide
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Femtosecond laser micro-nano processing for boosting bubble releasing of gas evolution reactions 被引量:1
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作者 Shuai zhang Lishuang Xu +8 位作者 Jie Wu Ying Yang chengxin zhang Haiyan Tao Jingquan Lin Licheng Huang Wencheng Fang Keying Shi Xiangting Dong 《Nano Research》 SCIE EI CSCD 2022年第2期1672-1679,共8页
Coupling effect of chemical composition and physical structure is a key factor to construct superaerophobic electrodes.Almost all reports about superaerophobic electrodes were aimed at precisely controlling morphology... Coupling effect of chemical composition and physical structure is a key factor to construct superaerophobic electrodes.Almost all reports about superaerophobic electrodes were aimed at precisely controlling morphology of loaded materials(constructing specific structure)and ignored the due role of substrate.Nevertheless,in this work,by using high precision and controllable femtosecond laser,hierarchical micro-nano structures with superaerophobic properties were constructed on the surface of silicon substrate(fs-Si),and such special super-wettability could be successfully inherited to subsequent self-supporting electrodes through chemical synthesis.Femtosecond laser processing endowed electrodes with high electrochemical surface area,strong physical structure,and remarkable superaerophobic efficacy.As an unconventional processing method,the reconstructed morphology of substrate surface bears the responsibility of superaerophobicity,thus liberating the structural constraints on loaded materials.Since this key of coupling effect is transferred from the loaded materials to substrate,we provided a new general scheme for synthesizing superaerophobic electrodes.The successful introduction of femtosecond laser will open a new idea to synthesize self-supporting electrodes for gas-involving reactions. 展开更多
关键词 femtosecond laser gas evolution reactions hydrogen evolution reaction superaerophobic electrodes bubbles releasing
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TripletGO: Integrating Transcript Expression Profiles with Protein Homology Inferences for Gene Function Prediction
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作者 Yi-Heng Zhu chengxin zhang +4 位作者 Yan Liu Gilbert S.Omenn Peter L.Freddolino Dong-Jun Yu Yang zhang 《Genomics, Proteomics & Bioinformatics》 SCIE CAS CSCD 2022年第5期1013-1027,共15页
Gene Ontology(GO)has been widely used to annotate functions of genes and gene products.Here,we proposed a new method,Triplet GO,to deduce GO terms of protein-coding and noncoding genes,through the integration of four ... Gene Ontology(GO)has been widely used to annotate functions of genes and gene products.Here,we proposed a new method,Triplet GO,to deduce GO terms of protein-coding and noncoding genes,through the integration of four complementary pipelines built on transcript expression profile,genetic sequence alignment,protein sequence alignment,and naīve probability.Triplet GO was tested on a large set of 5754 genes from 8 species(human,mouse,Arabidopsis,rat,fly,budding yeast,fission yeast,and nematoda)and 2433 proteins with available expression data from the third Critical Assessment of Protein Function Annotation challenge(CAFA3).Experimental results show that Triplet GO achieves function annotation accuracy significantly beyond the current state-of-the-art approaches.Detailed analyses show that the major advantage of Triplet GO lies in the coupling of a new triplet network-based profiling method with the feature space mapping technique,which can accurately recognize function patterns from transcript expression profiles.Meanwhile,the combination of multiple complementary models,especially those from transcript expression and protein-level alignments,improves the coverage and accuracy of the final GO annotation results.The standalone package and an online server of Triplet GO are freely available at https://zhanggroup.org/Triplet GO/. 展开更多
关键词 Gene function annotation Gene Ontology Transcript expression profile Triplet network Protein-level alignment
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