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8篇 您的检索式:作者名="Youjiang He"
    题名 作者 年代 出处 被引量
1Aerosol effects on ozone concentrations in Beijing:A model sensitivity study显示文摘Most previous O 3 simulations were based only on gaseous phase photochemistry.However,some aerosol-related processes,namely,heterogeneous reactions occurring on the aerosol surface and photolysis rate alternated by aerosol radiative influence,may affect O 3 photochemistry under high aerosol loads.A three-dimensional air quality model,Models-3/Community Multi-scale Air Quality-Model of Aerosol Dynamics,Reaction,Ionization,and Dissolution,was employed to simulate the effects of the above-mentioned processes on O 3 formation under typical high O 3 episodes in Beijing during summer.Five heterogeneous reactions,i.e.,NO 2,NO 3,N 2 O 5,HO 2,and O 3,were individually investigated to elucidate their effects on O 3 formation.The results showed that the heterogeneous reactions significantly affected O 3 formation in the urban plume.NO 2 heterogeneous reaction increased O 3 to 90 ppb,while HO 2 heterogeneous reaction decreased O 3 to 33 ppb.In addition,O 3 heterogeneous loss decreased O 3 to 31 ppb.The effects of NO 2,NO 3,and N 2 O 5 heterogeneous reactions showed opposite O 3 concentration changes between the urban and extra-urban areas because of the response of the reactions to the two types of O 3 formation regimes.When the aerosol radiative influence was included,the photolysis rate decreased and O 3 decreased significantly to 73 ppb O 3.The two aerosol-related processes should be considered in the study of O 3 formation because high aerosol concentration is a ubiquitous phenomenon that affects the urban-and regional air quality in China.Jun Xu Yuanhang Zhang Shaoqing Zheng Youjiang He 2012Journal of Environmental Sciences2012,24,4:15
2An overview of emissions of SO2 and NOx and the long-range transport of oxidized sulfur and nitrogen pollutants in East Asia显示文摘The long-range transport of oxidized sulfur(sulfur dioxide(SO_2) and sulfate) and oxidized nitrogen(nitrogen oxides(NO_x ) and nitrate) in East Asia is an area of increasing scientific interest and political concern. This paper reviews various published papers, including ground- and satellite-based observations and numerical simulations. The aim is to assess the status of the anthropogenic emissions of SO_2 and NO_x and the long-range transport of oxidized S and N pollutants over source and downwind region. China has dominated the emissions of SO_2 and NO_x in East Asia and urgently needs to strengthen the control of their emissions, especially NO_x emissions. Oxidized S and N pollutants emitted from China are transported to Korea and Japan, due to persistent westerly winds, in winter and spring.However, the total contributions of China to S and N pollutants across Korea and Japan were not found to be dominant over longer time scales(e.g., a year). The source–receptor relationships for oxidized S and N pollutants in East Asia varied widely among the different studies. This is because:(1) the nonlinear effects of atmospheric chemistry and deposition processes were not well considered, when calculating the source–receptor relationships;(2) different meteorological and emission data inputs and solution schemes for key physical and chemical processes were used; and(3) different temporal and spatial scales were employed. Therefore, simulations using the same input fields and similar model configurations would be of benefit, to further evaluate the source–receptor relationships of the oxidized S and N pollutants.Yu Qu Junling An Youjiang He Jun Zheng 2016Journal of Environmental Sciences2016,28,6:8
3Aircraft Measurements of the Microphysical Properties of Stratiform Clouds with Embedded Convection显示文摘The presence of embedded convection in stratiform clouds strongly affects ice microphysical properties and precipitation formation.In situ aircraft measurements,including upward and downward spirals and horizontal penetrations,were performed within both embedded convective cells and stratiform regions of a mixedphase stratiform cloud system on 22 May 2017.Supercooled liquid water measurements,particle size distributions,and particle habits in different cloud regions were discussed with the intent of characterizing the riming process and determining how particle size distributions vary from convective to stratiform regions.Significant amounts of supercooled liquid water,with maxima up to 0.6 g m−3,were observed between−3℃ and−6℃ in the embedded convective cells while the peak liquid water content was generally less than 0.1 g m−3 in the stratiform regions.There are two distinct differences in particle size distributions between convective and stratiform regions.One difference is the significant shift toward larger particles from upper−15℃ to lower−10℃ in the convective region,with the maximum particle dimensions increasing from less than 6000μm to over 1 cm.The particles larger than 1 cm at−10℃ are composed of dendrites and their aggregates.The other difference is the large concentrations of small particles(25–205μm)at temperatures between−3℃ and−5℃ in the convective region,where rimed ice particles and needles coexist.Needle regions are observed from three of the five spirals,but only the cloud conditions within the convective region fit into the Hallett-Mossop criteria.Tuanjie HOU Hengchi LEI Youjiang HE Jiefan YANG Zhen ZHAO Zhaoxia HU 2021Advances in Atmospheric Sciences2021,38,6:3
4SO_2 emission cap planning for Chengdu-Chongqing economic zone显示文摘The SO 2 emission sources of the Chengdu-Chongqing economic zone were divided into 556 emissions units according to four different categories,which are city,industry,point sources,and area sources.The CALPUFF model was used to calculate the contribution of each unit,and consequently obtain an influence-transferring matrix.To ensure that the SO 2 concentrations of 46 cities and counties in the Chengdu-Chongqing economic zone meet air quality standards,an emission optimization model was developed to calculate optimal emissions of each emission unit under different development scenarios.The result showed the optimal emissions of SO 2 by different provinces and industries.To achieve the target of restricting and optimizing development,corresponding planning programs were developed for every district.Peng Yi Ning Duan Fahe Chai Yaxuan Xu Youjiang He 2012Journal of Environmental Sciences2012,24,1:3
5Analysis of the origin of peak aerosol optical depth in springtime over the Gulf of Tonkin显示文摘By aggregating MODIS(moderate-resolution imaging spectroradiometer) AOD(aerosol optical depth) and OMI(ozone monitoring instrument) UVAI(ultra violet aerosol index)datasets over 2010–2014, it was found that peak aerosol loading in seasonal variation occurred annually in spring over the Gulf of Tonkin(17–23°N, 105–110°E). The vertical structure of the aerosol extinction coefficient retrieved from the spaceborne lidar CALIOP(cloud-aerosol lidar with orthogonal polarization) showed that the springtime peak AOD could be attributed to an abrupt increase in aerosol loading between altitudes of 2 and 5 km.In contrast, aerosol loading in the low atmosphere(below 1 km) was only half of that in winter. Wind fields in the low and high atmosphere exhibited opposite transportation patterns in spring over the Gulf of Tonkin, implying different sources for each level. By comparing the emission inventory of anthropogenic sources with biomass burning, and analyzing the seasonal variation of the vertical structure of aerosols over the Northern Indo-China Peninsula(NIC), it was concluded that biomass burning emissions contributed to high aerosol loading in spring. The relatively high topography and the high surface temperature in spring made planetary boundary layer height greater than 3 km over NIC. In addition, small-scale cumulus convection frequently occurred, facilitating pollutant rising to over 3 km, which was a height favoring long-range transport. Thus, pollutants emitted from biomass burning over NIC in spring were raised to the high atmosphere, then experienced long-range transport, leading to the increase in aerosol loading at high altitudes over the Gulf of Tonkin during spring.Xiaoli Shan Jun Xu Yixue Li Feng Han Xiaohui Du Jingying Mao Yunbo Chen Youjiang He Fan Meng Xuezhi Dai 2016Journal of Environmental Sciences2016,28,2:2
6Measurement of hydrogen peroxide and organic hydroperoxide concentrations during autumn in Beijing, China显示文摘Gaseous peroxides play important roles in atmospheric chemistry. To understand the pathways of the formation and removal of peroxides, atmospheric peroxide concentrations and their controlling factors were measured from 7:00 to 20:00 in September, October, and November 2013 at a heavily trafficked residential site in Beijing, China, with average concentrations of hydrogen peroxide(H_2O_2) and methyl hydroperoxide(MHP) at 0.55 ppb and 0.063 ppb, respectively. H_2O_2 concentrations were higher in the afternoon and lower in the morning and evening, while MHP concentrations did not exhibit a regular diurnal pattern. Both H_2O_2 and MHP concentrations increased at dusk in most cases. Both peroxides displayed monthly variations with higher concentrations in September. These results suggested that photochemical activity was the main controlling factor on variations of H_2O_2 concentrations during the measurement period. Increasing concentrations of volatile organic compounds emitted by motor vehicles were important contributors to H_2O_2 and MHP enrichment. High levels of H_2O_2 and MHP concentrations which occurred during the measurement period probably resulted from the transport of a polluted air mass with high water vapor content passing over the Bohai Bay, China.Qingyu Zhang Jiaoyu Liu Youjiang He Jiaying Yang Jian Gao Houfeng Liu Wei Tang Yizhen Chen Wenhao Fan Xuan Chen Fahe Chai Shiro Hatakeyama 2018Journal of Environmental Sciences2018,30,2:2
7Review on recent progress in on-line monitoring technology for atmospheric pollution source emissions in China显示文摘Emissions from mobile sources and stationary sources contribute to atmospheric pollution in China,and its components,which include ultrafine particles(UFPs),volatile organic compounds(VOCs),and other reactive gases,such as NH3and NOx,are the most harmful to human health.China has released various regulations and standards to address pollution from mobile and stationary sources.Thus,it is urgent to develop online monitoring technology for atmospheric pollution source emissions.This study provides an overview of the main progress in mobile and stationary source monitoring technology in China and describes the comprehensive application of some typical instruments in vital areas in recent years.These instruments have been applied to monitor emissions from motor vehicles,ships,airports,the chemical industry,and electric power generation.Not only has the level of atmospheric environment monitoring technology and equipment been improving,but relevant regulations and standards have also been constantly updated.Meanwhile,the developed instruments can provide scientific assistance for the successful implementation of regulations.According to the potential problem areas in atmospheric pollution in China,some research hotspots and future trends of atmospheric online monitoring technology are summarized.Furthermore,more advanced atmospheric online monitoring technology will contribute to a comprehensive understanding of atmospheric pollution and improve environmental monitoring capacity.Huanqin Wang Jitong Zhou Xue Li Qiang Ling Hongyuan Wei Lei Gao Ying He Ming Zhu Xiao Xiao Youjiang Liu Shan Li Chilai Chen Guotao Duan Zhimin Peng Peili Zhou Yufeng Duan Jianbing Wang Tongzhu Yu Yixin Yang Jiguang Wang Zhen Zhou Huaqiao Gui Yanjun Ding 2023Journal of Environmental Sciences2023,,1:0
8Evaluation of the Predicted Particle Properties (P3) Microphysics Scheme in Simulations of Stratiform Clouds with Embedded Convection显示文摘To evaluate the ability of the Predicted Particle Properties(P3)scheme in the Weather Research and Forecasting(WRF)model,we simulated a stratiform rainfall event over northern China on 22 May 2017.WRF simulations with two P3 versions,P3-nc and P3-2ice,were evaluated against rain gauge,radar,and aircraft observations.A series of sensitivity experiments were conducted with different collection efficiencies between ice and cloud droplets.The comparison of the precipitation evolution between P3-nc and P3-2ice suggested that both P3 versions overpredicted surface precipitation along the Taihang Mountains but underpredicted precipitation in the localized region on the leeward side.P3-2ice had slightly lower peak precipitation rates and smaller total precipitation amounts than P3-nc,which were closer to the observations.P3-2ice also more realistically reproduced the overall reflectivity structures than P3-nc.A comparison of ice concentrations with observations indicated that P3-nc underestimated aggregation,whereas P3-2ice produced more active aggregation from the self-collection of ice and ice-ice collisions between categories.Efficient aggregation in P3-2ice resulted in lower ice concentrations at heights between 4 and 6 km,which was closer to the observations.In this case,the total precipitation and precipitation pattern were not sensitive to riming.Riming was important in reproducing the location and strength of the embedded convective region through its impact on ice mass flux above the melting level.Tuanjie HOU Baojun CHEN Hengchi LEI Lei WEI Youjiang HE Qiujuan FENG 2023Advances in Atmospheric Sciences2023,40,10:0
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