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Input function and simulated distributions of tritium in the North Pacific

Science china Earth sciences 2010年第3期53卷 441-453页

作者： ba qi1,2 & xu yongfu1 1 state key laboratory of atmospheric boundary layer physics and atmospheric chemistry, institute of atmospheric physics, chinese academy of sciences, beijing 100029, china 2 Graduate University of chinese academy of sciences, beijing 100049, china 1. state key laboratory of atmospheric boundary layer physics and atmospheric chemistry Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China

An ocean general circulation model (OGCM) of the North Pacific with a southern open boundary condition is used to simulate the distribution and transport of tritium in the North Pacific. First, the observed tritium in precipitation dataset of GNIP/ISOHIS is chosen, and used to develop an input function of tritium for the model domain from 1951 to 1997 in terms of the triangulation for interpolation. Then, the input function is used as an upper flux for the tritium model. The OGCM with tritium is integrated for 47 years with the initial condition of zero tritium concentrations. Compared with the observations from GEOSECS and WOCE, the model generates a meridional gradient of surface tritium concentrations and the high tritium concentrations in the subsurface layer, which is consistent with that indicated in the observations. The simulated time series of total tritium fluxes from the atmosphere to the ocean shows a spike in 1963. The total inventory of tritium in the ocean changes slowly with time after 1975. Tritium enters the higher-latitude region, and then is mainly transported by the subsurface process towards the equatorial region, which is well simulated in the model. However, the difference mainly occurs at 30°N–40°N, which can be seen also in the simulation of CFCs. This difference may partly originate from the insufficient description of physical processes in the OGCM. Nevertheless, some uncertainties exist in the development of the tritium input function, which can also influence the simulated results.

关键词： North Pacific basin-wide ocean general circulation model tritium input function tritium distributions

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解析北京郊区一次典型臭氧污染的物理化学过程

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大气科学 2024年第1期48卷 391-404页

作者：贾龙于姗杉徐永福中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室北京100029 中国科学院大学地球与行星科学学院大气化学与环境科学系北京100049

臭氧污染是我国当前面临的重要大气环境问题,其不仅取决于大气化学反应过程,而且会受大气物理过程和各气象要素的影响,因此需要从化学和物理两个方向来研究近地面臭氧污染问题。本研究结合外场观测和欧拉光化学模式,解析了2022年秋季北... 详细信息

臭氧污染是我国当前面临的重要大气环境问题,其不仅取决于大气化学反应过程,而且会受大气物理过程和各气象要素的影响,因此需要从化学和物理两个方向来研究近地面臭氧污染问题。本研究结合外场观测和欧拉光化学模式,解析了2022年秋季北京怀柔城区的一次光化学污染周期内的物理和化学过程。给出了温度、湿度和风速等气象因子,以及臭氧及其前体物挥发性有机物(VOCs)和氮氧化物(NO_(x),x=1、2)在此期间的日变化特征。通过源解析得到VOCs主要来源为交通排放(46%)、植物源(25%)、溶剂挥发(23%)和燃烧源(9%)。通过欧拉光化学模式确定了区域传输和本地VOCs对臭氧的贡献,结果显示强北风天气条件下,怀柔区臭氧以外来水平输送为主(贡献超过70%);当以弱的南风或东南风为主时,天气处于稳定状态,臭氧主要来自VOCs和NO_(x)的二次转化。根据VOCs的臭氧潜势,在所有VOCs中对臭氧贡献最大的物质为烯烃,其贡献为67%,其次为芳香烃(16%)。通过敏感度分析,发现臭氧生成对物理因子中的光强、温度和边界层高度最敏感;在臭氧前体物中,活性较强的烯烃类物质的敏感度最高,烷烃最低。最后基于本地VOCs特征的EKMA曲线,提出了控制臭氧污染的减排策略。

关键词：臭氧挥发性有机物源解析敏感性分析怀柔

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Effects of relative humidity on the characterization of a photochemical smog chamber

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Journal of Environmental sciences 2011年第12期23卷 2013-2018页

作者： Gaoshuo Hu yongfu xu Long Jia state key laboratory of atmospheric boundary layer physics and atmospheric chemistry Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate University of chinese academy of sciences Beijing 100049 China

Water vapor plays an important role in many atmospheric chemical reactions. A self-made indoor environmental smog chamber was used to investigate the effects of relative humidity （RH） on its characterization, which included the wall effects of reactive species such as O3 and NOx, and the determination of chamber-dependent OH radicals in terms of CO-NOx irradiation experiments. Results showed that the rate constant of O3 wall losses increased with increasing RH, and that their relationship was linearly significant. Although RH aflected the rate constant of NOx wall losses, their relationship was not statistically significant. background air generated a small amount of ozone at both high and low RH. When RH varied from 5% to 79%, the apparent rate constant kNO2→HONO for the conversion of NO2 into gas phase HONO was estimated in the range of 0.70×10-3–2.5×10-3 min-1. A linear relationship between kNO2→HONO and RH was obtained as kNO2→HONO （10-3 min-1） = –0.0255RH ＋ 2.64, with R2 and P value being 0.978 and 0.01. To our knowledge, this is the first report on their relationship. The generation mechanism for HONO and OH was also discussed in this work.

关键词： chamber characterization relative humidity wall effects OH radicals

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Smog Chamber Study on the Ozone Formation Potential of Acetaldehyde

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Advances in atmospheric sciences 2021年第7期38卷 1238-1251页

作者： Hailiang ZHANG yongfu xu Long JIA Min xu state key laboratory of atmospheric boundary layer physics and atmospheric chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Department of atmospheric chemistry and Environmental sciences College of Earth and Planetary SciencesUniversity of Chinese Academy of SciencesBeijing 100049China

Acetaldehyde is one of the important VOC species of O_(3)precursors in the atmospheric *** influences of relative humidity(RH)and initial VOC/NOx ratio(R_(CN))on the formation of O_(3)are studied in smog chamber experiments,and the MCM v3.3.1 mechanism of acetaldehyde is modified based on the experimental *** low-RH conditions(RH=11.6%±1.1%),the O_(3)concentration at 6 h increases first and then decreases with the increase of R_(CN),and the R_(CN)at the inflection point of O_(3)concentrations is *** high-RH experiments(RH=78.8%±1.0%),variation of the O_(3)concentration at 6 h with R_(CN)is similar to that in low-RH experiments,but the R_(CN)at the inflection point is *** has no significant effect on the O_(3)concentrations under low R_(CN)(3).Compared with the experimental results,original MCM v3.3.1 greatly underestimates the O_(3)*** of both the photolysis process of peroxyacetyl nitrate and the photolysis process of HNO_(3)on the reactor surface into the original MCM can reduce the difference between the simulated O_(3)concentrations and the experimental results at 6 h from 24%−35%and 17%−49%to 6%−26%and 10%−42%under low-and high-RH conditions,*** maximum incremental reactivity(MIR)of acetaldehyde simulated with the modified MCM is 4.0 ppb ppb−1 without considering the effect of other VOCs.

关键词： ozone acetaldehyde photochemical reaction MCM

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Wall losses of oxygenated volatile organic compounds from oxidation of toluene:Effects of chamber volume and relative humidity

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Journal of Environmental sciences 2022年第4期34卷 475-484页

作者： Shanshan Yu Long Jia yongfu xu Hailiang Zhang Qun Zhang Yuepeng Pan state key laboratory of atmospheric boundary layer physics and atmospheric chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Department of atmospheric chemistry and Environmental sciences College of Earth and Planetary SciencesUniversity of Chinese Academy of SciencesBeijing 100049China

Vapor wall losses can affect the yields of secondary organic *** effects of surfaceto-volume(S/V)ratio and relative humidity(RH)on the vapor-wall interactions were investigated in this *** oxygenated volatile organic compounds(OVOCs)were generated from toluene-H_(2)O_(2)*** average gas to wall loss rate constant(k_(gw))of OVOCs in a 400 L reactor(S/V=7.5 m^(-1))is 2.47(2.41 under humid conditions)times higher than that in a 5000 L reactor(S/V=3.6 m-1)under dry *** contrast,the average desorption rate constant(k_(wg))of OVOCs in 400 L reactor is only 1.37(1.20 under humid conditions)times higher than that in 5000 L reactor under dry *** shows that increasing the S/V ratio can promote the wall losses of *** contrast,the RH effect on k_(gw)is not *** average k_(gw)value under humid conditions is almost the same as under dry conditions in the 400 L(5000 L)***,increasing RH can decrease the desorption *** average k_(wg)value under dry conditions is 1.45(1.27)times higher than that under humid conditions in the 400 L(5000 L)*** high RH can increase the partitioning equilibrium timescales and enhance the wall losses of OVOCs.

关键词： Vapor wall loss Surface-to-volume ratio Relative humidity Toluene Smog chamber Oxygenated volatile organic compounds

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Smog chamber studies of ozone formation potentials for isopentane

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chinese Science Bulletin 2009年第24期54卷 4624-4632页

作者： JIA Long xu yongfu GE MaoFa DU Lin ZHUANG GuoShun state key laboratory of atmospheric boundary layer physics and atmospheric chemistry Institute of Atmospheric Physics Chi- nese Academy of Sciences Beijing 100029 China Research Center for atmospheric Environment Beijing Normal University Beijing 100875 China beijing National laboratory for Molecular sciences State Key Laboratory for Structural Chemistry of Unstable and Stable Species Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China

The incremental reactivity and ozone formation potential of isopentane have been studied with chamber experiments and computer simulations. The chemical mechanism used in the computer simulations is an isopentane sub-mechanism from the Master Chemical Mechanism (MCM). The results from the chamber experiments suggest that the MCM can well simulate i-C5H12-NOx chamber experiments. The heterogeneous reaction of NO2 and water is an important source for OH radicals in the chamber experiments. The photolysis of HONO is responsible for the initiation of isopentane in photochemical reactions. The reaction rate constant for NO2 → HONO was determined to be 3.9×10-4―5.9×10-3 min-1 by conducting 3 sets of CO-NOx-air irradiations. 5 sets of isopentane-NOx irradiations under different conditions were performed in our chamber. Compared with the experiment with a low relative humidity (RH), an increase in RH can increase the reaction rate of NO2 with H2O, so that the peak ozone occurs earlier. When isopentane is predominant over NOx, the peak ozone concentration is largely dependent on NOx concentrations.

关键词：臭氧浓度异戊烷计算机模拟光化学反应发生高峰期潜能雾室氮氧化物

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Experimental investigation of incremental reactivity of di-tert-butyl peroxide

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chinese Science Bulletin 2007年第12期52卷 1629-1634页

作者： DU Lin xu yongfu GE MaoFa JIA Long YAO Li beijing National laboratory for Molecular sciences (BNLMS) State Key Laboratory for Structural Chemistry of Unstable and Stable Species Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China state key laboratory of atmospheric boundary layer physics and atmospheric chemistry Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate University of the chinese academy of sciences Beijing 100039 China Research Center for atmospheric Environment Beijing Normal University Beijing 100875 China

Large quantities of di-tert-butyl peroxide (DTBP) have been emitted into the troposphere due to human activities. Its role in the atmospheric photochemical reaction has not been understood. This study presents the results of the photochemical reactions of DTBP and NOx, which have been simulated in a self-made smog chamber under the temperature of (29±1)℃. Both the wall decays of ozone and NO2 could be neglected, compared to the results in simulative experiments. The effective intensity of UV light used in the experiments was 1.28×10-3 s-1, which was expressed by the rate constant of NO2 photolysis in purified air. The reaction mechanism was proposed according to our results and reports of other researchers. The maximum values of incremental reactivity (IR) in the three simulative ex- periments were 9.53×10-2, 5.23×10-2 and 3.78×10-2, respectively. The incremental reactivity decreased with the increase of initial concentrations of DTBP. The IR value of DTBP obtained in this study was comparable to that of acetylene reported in our previous research.

关键词：双特丁基过氧化物烟雾室光化反应光化烟雾大气化学

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A kinetic study of the reaction of ozone with ethylene in a smog chamber under atmospheric conditions

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chinese Science Bulletin 2006年第23期51卷 2839-2843页

作者： xu yongfu JIA Long GE Maofa DU Lin WANG Gengchen WANG Dianxun state key laboratory of atmospheric boundary layer physics and atmospheric chemistry Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Research Center for atmospheric Environment Beijing Normal University Beijing 100875 China institute of chemistry Chinese Academy of Sciences Beijing 100080 China Division for Middle Atmosphere and Remote Sensing Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

Ozone is one of the key species in the processes of atmospheric chemistry, which can be taken as an indicator of oxidation capacity in the troposphere. The reaction of ozone with reactive gases is an important process in the troposphere. Experimental simulation equipment of smog chamber for atmospheric reactions is used to study the reaction of ozone with ethylene in real atmospheric environment with ozone concentrations of 100―200 ppb. The concentrations of ozone and ethylene were moni-tored during the reaction with the combination of Model 49C-O_3 Analyzer and GC-FID. A rate constant of 1.01×10^(-18) (cm^3·mol^(-1)·s-(~1)) was obtained at 286.5 K, under condition of which the half-life of ozone was 88 min. The results obtained from our experiments are in excellent agreement with those reported previously by other researchers under extremely low pressure in terms of matrixisolation technology. This demonstrates that our equipment of smog chamber for atmospheric reactions is reliable, which can be used for further research of the processes of atmospheric reactions.

关键词：臭氧乙烯反作用力动力学比率常量气相反应

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大气条件下O_3与乙炔反应速率常数的测定

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化学学报 2006年第21期64卷 2133-2137页

作者：杜林徐永福葛茂发贾龙王庚辰王殿勋中国科学院化学研究所北京分子科学国家实验室北京100080 中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室北京100029 北京师范大学大气环境研究中心北京100875 中国科学院大气物理研究所中层大气遥感与探测开放实验室北京100029

O3是对流层大气中一种重要的氧化剂,其与反应活性气体的反应是大气对流层中重要的反应过程,对于研究空气污染的对策有重要意义.我们使用自行建设的烟雾箱模拟反应装置,结合O3分析仪和气相色谱研究了O3和乙炔的反应.研究测得O3和乙炔在... 详细信息

O3是对流层大气中一种重要的氧化剂,其与反应活性气体的反应是大气对流层中重要的反应过程,对于研究空气污染的对策有重要意义.我们使用自行建设的烟雾箱模拟反应装置,结合O3分析仪和气相色谱研究了O3和乙炔的反应.研究测得O3和乙炔在室温下(15℃)反应的4次实验的速率常数的平均值为4.13×10-21cm3?molecule-1?s-1,其变动系数为7%.与文献中采用其它方法得到的实验值相吻合.所得结果表明,我们测定的反应速率常数有较高的精密度,我们所建的大气反应烟雾箱模拟系统是可靠的,可以用于大气O3浓度条件下O3的其它大气化学反应过程的深入研究,为进一步深入研究大气中其它重要反应活性气体的化学反应提供了一定的基础.

关键词：臭氧乙炔动力学反应速率常数

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Refractory black carbon aerosols in rainwater in the summer of 2019 in beijing:Mass concentration,size distribution and wet scavenging ratio

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Journal of Environmental sciences 2023年第10期132卷 31-42页

作者： Shandong Lei baozhu Ge Hang Liu Jiannong Quan Danhui xu Yuting Zhang Weijie Yao Lu Lei Yu Tian qi Liao Xiaoyong Liu Jie Li Jinyuan Xin Yele Sun Pingqing Fu Junji Cao Zifa Wang Xiaole Pan state key laboratory of atmospheric boundary layer physics and atmospheric chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary sciences University of Chinese Academy of SciencesBeijing 100049China institute of Urban Meteorology China Meteorological AdministrationBeijing 100089China National Center for Climate Change Strategy and International Cooperation Ministry of Ecology and EnvironmentBeijing 100035China Center for Excellence in Regional atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and TechnologyNanjing 210044China institute of Surface-Earth System Science Tianjin UniversityTianjin 300072China institute of atmospheric physics Chinese Academy of SciencesBeijing 100190China

Black carbon(BC)aerosols in the atmosphere play a significant role in climate systems due to their strong ability to absorb solar *** lifetime of BC depends on atmospheric transport,aging and consequently on wet scavenging processes(in-cloud and below-cloud scavenging).In this study,sequential rainwater samples in eight rainfall events collected in 2 mm interval were measured by a tandem system including a single particle soot photometer(SP2)and a *** results showed that the volume-weighted average(VWA)mass concentrations of refractory black carbon(rBC)in each rainfall event varied,ranging from 10.8 to 78.9μg/*** highest rBC concentrations in the rainwater samples typically occurred in the first fraction from individual rainfall *** geometric mean median mass-equivalent diameter(MMD)decreased under precipitation,indicating that rBC with larger sizes was relatively aged and preferentially removed by wet scavenging.A positive correlation(R2=0.73)between the VWA mass concentrations of rBC in rainwater and that in ambient air suggested the important contribution of scavenging ***,the contributions of in-cloud and below-cloud scavenging were distinguished and accounted for 74%and 26%to wet scavenging,*** scavenging ratio of rBC particles was estimated to be 0.06 on *** study provides helpful information for better understanding the mechanism of rBC wet scavenging and reducing the uncertainty of numerical simulations of the climate effects of rBC.

关键词： Refractory black carbon Wet deposition Size distribution

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