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On-line Measurement of Water-Soluble Ions in Ambient Particles

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Advances in atmospheric Sciences 2006年第4期23卷 586-592页

作者：温天雪王跃思张士昱刘广仁 State Key Laboratory of atmospheric Boundary Layer Physics and atmospheric chemistry (LAPC) Institute of atmospheric Physics Chinese Academy of Sciences Environment Change Research centre Taipei

Combining the system of rapid collection of ambient particles and ion chromatography, the system of rapid collection of fine particles and ion chromatography （RCFP-IC） was established to automatically analyze on-line the concentrations of water-soluble ions in ambient particles. Here, the general scheme of RCFP-IC is described and its basic performance is tested. The detection limit of RCFP-IC for SO4^2-, NO3^-, NO2^-, Cl^- and F- is below 0.3μg m^-3. The collection efficiency of RCFP-IC increases rapidly with increasing sized particles. For particles larger than 300 nm, the collection efficiency approaches 100%. The precision of RCFP-IC is more than 90% over 28 repetitions. The response of RCFP-IC is very sensitive and no obvious cross-pollution is found during measurement. A comparison of RCFP-IC with an integrated filter measurement indicates that the measurement of RCFP-IC is comparable in both laboratory experiments and field observations. The results of the field experiment prove that RCFP-IC is an effective on-line monitoring system and is helpful in source apportionment and pollution episode monitoring.

关键词： RCFP-IC water-soluble ions on-line basic performance field observation

Wintertime peroxyacetyl nitrate(PAN) in the megacity Beijing: Role of photochemical and meteorological processes

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Journal of Environmental Sciences 2014年第1期26卷 83-96页

作者： Hualong Zhang Xiaobin Xu Weili Lin Ying Wang Key Laboratory for atmospheric chemistry China Meteorological Administration Institute of Atmospheric Composition Chinese Academy of Meteorological Sciences Meteorological Observation centre China Meteorological Administration

Previous measurements of peroxyacetyl nitrate （PAN） in Asian megacities were scarce and mainly conducted for relative short periods in summer. Here, we present and analyze the measurements of PAN, O3, NOx, etc., made at an urban site （CMA） in Beijing from 25 January to 22 March 2010. The hourly concentration of PAN averaged 0.70 × 10^-9 mol/mol （0.23 × 10^9-3.51 × 10^9 mol/mol） and was well correlated with that of NOa but not O3, indicating that the variations of the winter concentrations of PAN and O3 in urban Beijing are decoupled with each other. Wind conditions and transport of air masses exert very significant impacts on O3, PAN, and other species. Air masses arriving at the site originated either from the boundary layer over the highly polluted N-S-W sector or from the free troposphere over the W-N sector. The descending free-tropospheric air was rich in O3, with an average PAN/O3 ratio smaller than 0.O31, while the boundary layer air over the polluted sector contained higher levels of PAN and primary pollutants, with an average PAN/O3 ratio of 0.11. These facts related with transport conditions can well explain the observed PAN-O3 decoupling. Photochemical production is important to PAN in the winter over Beijing. The concentration of the peroxyacetyl （PA） radicai was estimated to be in the range of 0.0014 × 10^-12～0.0042 × 10^-12 mol/mol. The contributions of the formation reaction and thermal decomposition to PAN＇s variation were calculated and found to be significant even in the colder period in air over Beijing, with the production exceeding the decomposition.

关键词： peroxyacetyl nitrate photochemical production wintertime urban Beijing

Observed levels and trends of gaseous SO_2 and HNO_3 at ***,China:Results from 1997 to 2009

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Journal of Environmental Sciences 2013年第4期25卷 726-734页

作者： Weili Lin Xiaobin Xu Xiaolan Yu Xiaochun Zhang Jianqing Huang centre for Atmosphere Watch and Services Meteorological Observation CentreChina Meteorological Administration Key Laboratory for atmospheric chemistry Chinese Academy of Meteorological Sciences Waliguan Observatory

Long-term measurements of SO2 and HNO3, particularly those from the background sites, are rarely reported. We present for the first time the long-term measurements of SO2 and HNO3 at Waliguan （WLG）, the only global baseline station in the back-land of the Eurasian Continent. The concentrations of SO2 and HNO3 were observed at WLG from 1997 to 2009. The observed annual mean concentrations of SO2 and HNO3 at WLG were 1.28 ± 0.41 and 0.22 ± 0.19 μg/m3, respectively. The HNO3 concentrations were much higher in warmer seasons than in colder seasons, while the SO2 concentrations showed a nearly reversed seasonal pattern. In most months, the concentration of HNO3 was significantly correlated with that of SO2, suggesting that some common factors influence the variations of both gases and the precursors of HNO3 may partially be from the SO2-emitting sources. The SO2 concentration had a very significant （P 〈 0.0001） decreasing trend （-0.2 μg/（***）） in 1997-2002, but a significant （P 〈 0.05） increasing trend （＋0.06 μg/（m3-yr）） in 2003-2009. The HNO3 concentration showed no statistically significant trend during 1997-2009. While the decrease of SO2 in 1997-2002 agrees with the trend of global SO2 emissions, the increase in 2003-2009 is not consistent with the decreasing trends in many other regions over the world. Trajectory analysis suggests that the airmasses from the northern Qinghai-Tibetan Plateau and the Takla Makan Desert regions contributed significantly to the increasing trends of SO2 and HNO3 at WLG in 2003-2009, with a rate of ＋0.13 μg/（***） and ＋0.007μg/（***）, respectively.

关键词： SO2 HNO3 long-term trends Waliguan global baseline

Two-year measurements of surface ozone at Dangxiong,a remote highland site in the Tibetan Plateau

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Journal of Environmental Sciences 2015年第5期27卷 133-145页

作者： Weili Lin Xiaobin Xu Xiangdong Zheng Jaxi Dawa Ciren Baima Jin Ma centre for Atmosphere Watch & Services Meteorological Observation Centre China Meteorological Administration Key Laboratory for atmospheric chemistry Chinese Academy of Meteorological Sciences Dangxiong Meteorological Bureau Lhasa Meteorological Bureau Department of atmospheric and Oceanic Sciences McGill University

Measurements of surface O3 and carbon monoxide（CO） were made from September 2009 to August 2011 at Dangxiong（30.48°N, 91.10°E, 4187 m a.s.l.）, a remote highland site in a southern valley of the Nyainqêntanglha Mountains in the Tibetan Plateau, China. The monthly mean O3 mixing ratio ranged from 29.1 to 51.4 ppb, with an average of 38.5 ppb, and the maximum value was observed in May. The average diurnal cycle of O3 concentration showed a minimum in early morning and a maximum in the afternoon, with a broader ＂high platform＂ from the late morning to the late afternoon, and resembled that of surface wind speed. The concentration of surface O3 was highly significantly correlated with tropospheric column O3 over the regions surrounding Dangxiong and with that of surface O3 observed at a site north of the Nyainqêntanglha Mountains, suggesting a good regional representativeness of surface O3 at Dangxiong. In the afternoon when stronger winds blew, surface air showed distinct features of free-atmospheric air, with higher O3, lower CO, and lower relative humidity（RH）. The negative O3-CO and O3-RH correlations in most months indicate a significant influence of air masses from the free troposphere. Trajectory analysis suggests that air masses originating from the south of the site make a negative net contribution to surface O3 and a positive contribution to CO and humidity, and those from the northwest sector contribute conversely to the respective quantities.

关键词： Surface ozone Tibetan Plateau Impact of transport and vertical mixing

Possible Impacts of the Arctic Oscillation on the Interdecadal Variation of Summer Monsoon Rainfall in East Asia

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Advances in atmospheric Sciences 2005年第1期22卷 39-48页

作者：琚建华吕俊梅曹杰任菊章 China Meteorological Administration Training centre Institute of atmospheric Physics Department of atmospheric Sciences

The influences of the wintertime AO (Arctic Oscillation) on the interdecadal variation of summer monsoon rainfall in East Asia were examined. An interdecadal abrupt change was found by the end of the 1970s in the variation of the AO index and the leading principal component time series of the summer rainfall in East Asia. The rainfall anomaly changed from below normal to above normal in central China, the southern part of northeastern China and the Korean peninsula around 1978. However, the opposite interdecadal variation was found in the rainfall anomaly in North China and South China. The interdecadal variation of summer rainfall is associated with the weakening of the East Asia summer monsoon circulation. It is indicated that the interdecadal variation of the AO exerts an influence on the weakening of the monsoon circulation. The recent trend in the AO toward its high-index polarity during the past two decades plays important roles in the land-sea contrast anomalies and wintertime precipitation anomaly. The mid- and high-latitude regions of the Asian continent are warming, while the low-latitude regions are cooling in winter and spring along with the AO entering its high-index polarity after the late 1970s. In the meantime, the precipitation over the Tibetan Plateau and South China is excessive, implying an increase of soil moisture. The cooling tendency of the land in the southern part of Asia will persist until summer because of the memory of soil moisture. So the warming of the Asian continent is relatively slow in summer. Moreover, the Indian Ocean and Pacific Ocean, which are located southward and eastward of the Asian land, are warming from winter to summer. This suggests that the contrast between the land and sea is decreased in summer. The interdecadal decrease of the land-sea heat contrast finally leads to the weakening of the East Asia summer monsoon circulation.

关键词： the Arctic Oscillation interdecadal variation summer monsoon rainfall land-sea heat contrast

Assessment of physicochemical properties of water and their seasonal variation in an urban river in Bangladesh

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Water Science and Engineering 2021年第2期14卷 139-148页

作者： Arafat Rahman Ishrat Jahanara Yeasmin Nahar Jolly Department of Soil Water and EnvironmentUniversity of DhakaDhaka 1000Bangladesh atmospheric and Environmental chemistry Laboratory Chemistry DivisionAtomic Energy CentreDhaka 1000Bangladesh

To assess the magnitude of water quality decline in the Turag River of Bangladesh,this study examined the seasonal variation of physi-cochemical parameters of water,identified potential pollution sources,and clustered the monitoring months with similar *** samples were collected in four distinct seasons to evaluate temperature,pH,dissolved oxygen(DO)concentration,five-day biochemical oxygen demand(BOD 5),chemical oxygen demand(COD),electrical conductivity(EC),chloride ion(Cl^(-))concentration,total alkalinity(TA),turbidity,total dissolved solids(TDS)concentration,total suspended solids(TSS)concentration,and total hardness(TH)using standard *** analytical results revealed that 40%of water quality indices were within the permissible limits suggested by different agencies,with the exception of EC,Cl^(-)concentration,TA,turbidity,DO concentration,BOD 5,and COD in all *** analyses indicated that 52%of the contrasts were significantly different at a 95%confidence *** factor analysis presented the best fit among the parameters,with four factors explaining 94.29%of the total ***,BOD 5,COD,EC,turbidity,DO,and Cl?were mainly responsible for pollution loading and were caused by the significant amount of industrial discharge and toxicological *** cluster analysis showed the seasonal change in surface water quality,which is usually an indicator of pollution from rainfall or other ***,the values of different physico-chemical properties varied with seasons,and the highest values of pollutants were recorded in the *** the change in seasonal tem-perature and increase in rainfall,the seasonal Turag River water followed a self-refining trend as follows:rainy season>pre-winter>summer>winter.

关键词： Seasonal variation Physicochemical parameter Water quality Factor analysis Cluster analysis Turag River

High-Resolution Hindcast of Record-Breaking Rainfall in Beijing and Impact of Topography

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atmospheric and Oceanic Science Letters 2013年第5期6卷 253-258页

作者： YU En-Tao SUN Jian-Qi XIANG Wei-Ling Nansen-Zhu International Research centre Institute of Atmospheric Physics Chinese Academy of Sciences State Key Laboratory of atmospheric Boundary Layer Physics and atmospheric chemistry Institute of Atmospheric Physics Chinese Academy of Sciences

In this paper,a hindcast study of the record-breaking rainfall event occurring in Beijing on 21July 2012,is conducted by using the Weather Research and Forecasting(WRF)model forced by National Centers for Environmental Prediction(NCEP)Global Forecasting System(GFS)outputs,paired with an investigation of the impact of topography in this *** results indicate that WRF can reasonably predict the salient features of orographic precipitation;the 24-h rainfall amount and spatial distribution compare reasonably well with the *** hindcast simulation also indicates that rainfall events can be predicted approximately 36 h *** the topography is removed,the spatial distribution of rainfall changes remarkably,suggesting the importance of the topography in determining rainfall *** results also indicate that prediction of such city-scale heavy rainfall events would benefit from a high-resolution prediction system.

关键词： record-breaking rainfall Beijing WRF topography

Parameterizing an agricultural production model for simulating nitrous oxide emissions in a wheat–maize system in the North China Plain

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atmospheric and Oceanic Science Letters 2016年第6期9卷 403-410页

作者： LI Ting-Ting ZHANG Wei WANG Jun ZHANG Wen WANG Guo-Cheng XU Jing-Jing ZHANG Qing State Key Laboratory of atmospheric Boundary Layer Physics and atmospheric chemistry Institute of Atmospheric PhysicsChinese Academy of Sciences Nansen-Zhu International Research centre Institute of Atmospheric PhysicsChinese Academy of Sciences

Concentrations of atmospheric nitrous oxide （N2O）, a potent greenhouse gas, have been continuously increasing, and cropland soils are one of the largest sources of N2O. Variations in environmental and anthropogenic factors have substantial impacts on both the frequency and magnitude of N2O emissions. Based on measurements from a wheat-maize system in the North China Plain, the authors parameterized the Agricultural Production Systems Simulator （APSIM） model, which was initially developed in Australia, for simulating N2O emissions under different agricultural management practices. After calibrating one of the key parameters -- the fraction of N2O lost in nitrification （k2） -- the results showed that the model successfully captured the daily N2O fluxes under different nitrogen fertilization treatments, but underestimated some large peak fluxes. By pooling all data together, the calibrated APSIM model also performed well in representing cumulative N2O emissions under various treatments at annual and finer （monthly and daily） time scales.

关键词： Agricultural productionmodeling nitrous oxide wheat-maize system North China Plain

An improved GC-ECD method for measuring atmospheric N_2O

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Journal of Environmental Sciences 2013年第3期25卷 547-553页

作者： Yuanyuan Zhang Yujing Mu Shuangxi Fang Junfeng Liu Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Key Laboratory for atmospheric chemistry Centre for Atmosphere Watch and ServicesChinese Academy of Meteorological Sciences

Gas chromatography equipped with an electron capture detector （GC-ECD） has been widely used for measuring atmospheric N2O,but nonlinear response and the influence of atmospheric CO2 have been recognized as defects for *** original GCECD method using N 2 as carrier gas was improved by introducing a small flow rate of CO2 makeup gas into the ECD,which could well remedy the above *** N2O signal of the improved method was 4-fold higher than that of the original method and the relative standard deviation was reduced from 〉 1% to 0.31%.N2O concentrations with different CO2 concentrations （172.2×10-6-1722×10-6mol/mol） measured by the improved GC-ECD method were in line with the actual N2O ***,the N2O concentrations detected by the original method were largely biased with a variation range of-4.5%～7%.The N2O fluxes between an agricultural field and the atmosphere measured by the original method were greatly overestimated in comparison with those measured by the improved *** linear correlation （R2=0.9996） between the response of the improved ECD and N2O concentrations （93×10-9-1966×10-9mol/mol） indicated that atmospheric N2O could be accurately quantified via a single standard *** N2O concentrations comparatively measured by the improved method and a high precision GC-ECD method were in good agreement.

关键词： N2O GC-ECD CO2 exchange flux method comparison