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Biogenic volatile organic compound analyses by PTR-TOF-MS: Calibration, humidity effect and reduced electric field dependency

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Journal of Environmental Sciences 2015年第6期27卷 196-206页

作者： Xiaobing Pang key laboratory for aerosol-cloud-precipitation of china meteorological administration Nanjing University of Information Science and Technology

Green leaf volatiles（GLVs） emitted by plants after stress or damage induction are a major part of biogenic volatile organic compounds（BVOCs）. Proton transfer reaction time-of-flight mass spectrometry（PTR-TOF-MS） is a high-resolution and sensitive technique for in situ GLV analyses, while its performance is dramatically influenced by humidity, electric field,etc. In this study the influence of gas humidity and the effect of reduced field（E/N） were examined in addition to measuring calibration curves for the GLVs. Calibration curves measured for seven of the GLVs in dry air were linear, with sensitivities ranging from 5 to10 ncps/ppbv（normalized counts per second/parts per billion by volume）. The sensitivities for most GLV analyses were found to increase by between 20% and 35% when the humidity of the sample gas was raised from 0% to 70% relative humidity（RH） at 21°C, with the exception of（E）-2-hexenol. Product ion branching ratios were also affected by humidity,with the relative abundance of the protonated molecular ions and higher mass fragment ions increasing with humidity. The effect of reduced field（E/N） on the fragmentation of GLVs was examined in the drift tube of the PTR-TOF-MS. The structurally similar GLVs are acutely susceptible to fragmentation following ionization and the fragmentation patterns are highly dependent on E/N. Overall the measured fragmentation patterns contain sufficient information to permit at least partial separation and identification of the isomeric GLVs by looking at differences in their fragmentation patterns at high and low E/N.

关键词： Biogenic volatile organic compound PTR-TOF-MS Humidity effect Reduced electric field

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Mixing state of individual carbonaceous particles during a severe haze episode in January 2013,Nanjing,china

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Particuology 2015年第3期13卷 16-23页

作者： Honglei Wang Bin Zhu Zefeng Zhang Junlin An Lijuan Shen Collaborative Innovation Center on Forecast and Evaluation of meteorological Disasters Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological AdministrationNanjing University of Information Science and Technology Jiaxing Environmental Monitoring Station

Chemical composition, hourly counts, and sizes of atmospheric carbonaceous particles were measured to investigate their mixing state on clear and hazy days. 823,122 carbonaceous particles with sizes 0.2-2.0μm was analyzed using a single-particle aerosol mass spectrometer from 1st to 17th January 2013. Particle types included biomass/biofuel burning particles （biomass）, element carbon （EC-dominant） particles that were also mixed with biomass/biofuel burning species （EC-biomass） or secondary species （EC-secondary）, organic carbon （OC）, internally mixed OC and EC （OCEC）, ammonium-containing （ammo- nium） and sodium-containing （sodium） particles. On clear days the top ranked carbonaceous particle types were biomass （48.2%）, EC-biomass （15.7%）, OCEC （11.1%）, and sodium （9.6%）, while on hazy days they were biomass （37.3%）, EC-biomass （17,6%）, EC-secondary （16.6%）, and sodium （12.7%）. The fractions of EC-secondary, ammonium （10%）, and sodium particle types were elevated on hazy days. Numbers of EC-secondary particles were more than four times those on clear days （4.1%）. Thus, carbonaceous particles mixed with ammonium, nitrate and sulfate during aging and transport, enhancing their light extinction effects and hygroscopic growth under high relative humidity on hazy days, further reducing visibility. Our real-time single-particle data showed that changes to mixing state had a significant impact on light extinction during haze events in Nanjing.

关键词： HazeSingle particleMixing stateSPAMSCarbonaceous particleSecondary aerosols

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Particle size distribution and characteristics of polycyclic aromatic hydrocarbons during a heavy haze episode in Nanjing,china

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Particuology 2015年第1期13卷 127-134页

作者： Qingzi Meng Shuxian Fan Jiabao He Jian Zhang Yu Sun Yue Zhang Fan Zu key laboratory for aerosol-cloud-precipitation of china meteorological administration Nanjing University of Information Science and Technology Department of Atmospheric Physics Nanjing University of Information Science and Technology Jiangsu Institute of meteorological Sciences

A heavy haze episode caused by agricultural burning occurred in Nanjing from November 7 to November 8, 2009. PM10 samples were collected on normal and hazy days from November I to November 14, 2009 at both city and suburban sites of Nanjing. Sixteen PAHs were measured during the day and at night. The results show that the concentrations of the particles were as high as 579.55 and 573.43 μg/m^3 during the haze episode at the city and suburban sites, respectively, 3-4 times higher than those on a normal day. The proportions of fine particles during the haze episode were also higher than those on a normal day. The changes in the concentrations of PAHs were in accordance with the concentrations of the particles. High- molecular-weight PAHs composed approximately 80% of the total PAHs on normal days and during the haze episode. The concentration of PAHs in fine fractions significantly increased during the haze episode, and this increase was most obvious at night at the city site, The proportion of total carcinogenic PAHs in fine particles was relatively high during the haze episode at both sampling sites, particularly at night at the city site.

关键词： Polycyclic aromatic hydrocarbons Agricultural burning Haze episode Particle size distribution meteorological conditions Nanjing

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Characteristics of cloud Water Resource and precipitation Efficiency of Hydrometeors over Northwest china

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Journal of meteorological Research 2023年第3期37卷 353-369页

作者： Zhanyu YAO Lin AN Pei ZHANG Liangshu GAO Shuo JIA Weijian WANG Wenhui ZHAO china meteorological administration cloud–precipitation Physics and Weather Modification key laboratory Weather Modification CentreChina Meteorological AdministrationBeijing 100081

Understanding the characteristics of cloud water resource(CWR)and precipitation efficiency of hydrometeors(PEh)is imperative for the application of CWR in Northwest *** atmospheric precipitable water(PW)in all four seasons and clouds and PEh in summer were studied with ERA-5 and cloudSat data in this *** results show that topography,especially in the Tibetan Plateau,exerts significant impacts on the precipitation and PW in summer,since large amounts of clouds are distributed along the mountain *** study region is divided into four typical areas:the monsoon area in eastern Northwest china(NWE),the Qilian Mountains area(QM),the Tianshan Mountains area(TM),and the Source of Three Rivers area(STR).Over the four areas,cloud top height(6.3 km)and cloud base height(3.3 km)over NWE are higher,and precipitating clouds are thicker(7 km)in the single-layer *** water content decreases with increasing altitude,while the ice water content first increases and then *** water path is higher over NWE(0.11 kg m^(−2))than over TM and STR(0.05 kg m^(−2)),and the ice water path is mainly concentrated within the range of 0.025–0.055 kg m^(−2).The PEh values are distributed unevenly and affected evidently by the *** the PEh values in the four typical areas(0.3–0.6)are higher than those in other regions,the CWR is relatively abundant and has a higher exploitation ***,it is well-founded to exploit CWR for alleviating water shortages in these areas of Northwest china in summer.

关键词： cloud water resource(CWR) precipitation efficiency of hydrometeors(PEh) precipitable water(PW) cloud Northwest china

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Preliminary Study on Direct Assimilation of cloud-affected Satellite Microwave Brightness Temperatures

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Advances in Atmospheric Sciences 2017年第2期34卷 199-208页

作者： Sibo ZHANG Li GUAN Collaborative Innovation Center on Forecast and Evaluation of meteorological Disasters Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological AdministrationNanjing University of Information Science and TechnologyNanjing 210044China

Direct assimilation of cloud-affected microwave brightness temperatures from AMSU-A into the GSI three-dimensional variational （3D-Var） assimilation system is preliminarily studied in this paper. A combination of cloud microphysics param- eters retrieved by the 1D-Var algorithm （including vertical profiles of cloud liquid water content, ice water content, and rain water content） and atmospheric state parameters from objective analysis fields of an NWP model are used as background fields. Three cloud microphysics parameters （cloud liquid water content, ice water content, and rain water content） are ap- plied to the control variable. Typhoon Halong （2014） is selected as an example. The results show that direct assimilation of cloud-affected AMSU-A observations can effectively adjust the structure of large-scale temperature, humidity and wind anal- ysis fields due to the assimilation of more AMSU-A observations in typhoon cloudy areas, especially typhoon spiral cloud belts. These adjustments, with temperatures increasing and humidities decreasing in the movement direction of the typhoon, bring the forecasted typhoon moving direction closer to its real path. The assimilation of cloud-affected satellite microwave brightness temperatures can provide better analysis fields that are more similar to the actual situation. Furthermore, typhoon prediction accuracy is improved using these assimilation analysis fields as the initial forecast fields in NWP models.

关键词： atmospheric sounding microwave remote sensing data assimilation cloudy radiances GSI

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Source analysis of spaceborne microwave radiometer interference over land

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Frontiers of Earth Science 2016年第1期10卷 135-144页

作者： Li GUAN Sibo ZHANG Collaborative Innovation Center on Forecast and Evaluation of meteorological Disasters Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration Nanjing University of Information Science & Technology Nanjing 210044 China

Satellite microwave thermal emissions mixed with signals from active sensors are referred to as radio- frequency interference （RFI）. Based on Advanced Micro- wave Scanning Radiometer-Earth Observing System （AMSR-E） observations from June 1 to 16, 2011, RFI over Europe was identified and analyzed using the modified principal component analysis algorithm in this paper. The X band AMSR-E measurements in England and Italy are mostly affected by the stable, persistent, active microwave transmitters on the surface, while the RFI source of other European countries is the interference of the reflected geostationary TV satellite downlink signals to the measurements of spacebome microwave radiometers. The locations and intensities of the RFI induced by the geostationary TV and communication satellites changed with time within the observed period. The observations of spacebome microwave radiometers in ascending portions of orbits are usually interfered with over European land, while no RFI was detected in descending passes. The RFI locations and intensities from the reflection of downlink radiation are highly dependent upon the relative geometry between the geostationary satellite and the measuring passive sensor. Only these fields of view of a spaceborne instrument whose scan azimuths are close to the azimuth relative to the geostationary satellite are likely to be affected by RFI.

关键词： AMSR-E RFI geostationary TV satellite

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Identifying AMSR-E radio-frequency interference over winter land

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Frontiers of Earth Science 2015年第3期9卷 437-448页

作者： Sibo ZHANG, Li GUAN Collaborative Innovation Center on Forecast and Evaluation of meteorological Disasters Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration Nanjing University of Information Science & Technology Nanjing 210044 China

Satellite microwave emission mixed with signals from active sensors is referred to as radio- frequency interference （RFI）. RFI affects greatly the quality of data and retrieval products from space-bome microwave radiometry. An accurate RFI detection will not only enhance geophysical retrievals over land but also provide evidence of the much-needed protection of the microwave frequency band for satellite remote sensing technologies. It is difficult to detect RFI from space-borne microwave radiometer data over winter land, because RFI signals are usually mixed with snow in mid-high latitudes. A modified principal component analysis （PCA） method is proposed in this paper for detecting microwave low frequency RFI signals. Only three original variables, one RFI index （sensitive to RFI signal） and two scattering indices （sensitive to snow scattering）, are included in the vector for principal component analysis in this modified method instead of the nine or seven RFI index original variables used in a normal PCA algorithm. The principal component with higher correlation and contribution to the original RFI index is the RFI-related principal component. In the absence of a reliable validation data set of the ＂true＂ RFI, the consistency in the identified RFI distribution obtained from this method compared to other independent methods, such as the spectral difference method, the normalized PCA method, and the double PCA method, give confidence to the RFI signals＇ identification over land. The simple and reliable modified PCA method could successfully detect RFI not only in summer but also in winter AMSR-E data.

关键词： microwave remote sensing radio-frequencyinterference (RFI) the Advanced Microwave ScanningRadiometer for Earth Observing System (AMSR-E),principal component analysis (PCA)

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Effect of Initial Vortex Intensity Correction on Tropical Cyclone Intensity Prediction:A Study Based on GRAPES_TYM

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Journal of meteorological Research 2020年第2期34卷 387-399页

作者： Liwen WANG Suhong MA key laboratory for aerosol–cloud–precipitation of china meteorological administration School of Atmospheric PhysicsNanjing University of Information Science&TechnologyNanjing 210044 National meteorological Center China Meteorological AdministrationBeijing 100081

Predicting the intensity of tropical cyclones(TCs)is challenging in operational weather prediction systems,partly due to the difficulty in defining the initial *** an attempt to solve this problem,this study investigated the effect of initial vortex intensity correction on the prediction of the intensity of TCs by the operational numerical prediction system GRAPES_TYM(Global and Regional Assimilation and Prediction System_Typhoon Model)of the National meteorological Center of the china meteorological *** statistical results based on experiments using data for major TCs in 2018 show that initial vortex intensity correction can reduce the errors in mean intensity for up to 120-h integration,with a noticeable decrease in the negative bias of intensity and a slight increase in the mean track *** correction leads to an increase in the correlation coefficient of Vmax(maximum wind speed at 10-m height)for the severe typhoon and super typhoon *** of the errors in intensity at different stages of intensity(including tropical storms,severe tropical storms,typhoons,severe typhoons,and super typhoons)show that vortex intensity correction has a remarkable positive influence on the prediction of super typhoons from 0 to *** of the errors in intensity for TCs with different initial intensities indicate that initial vortex correction can significantly improve the prediction of intensity from 24 to 96 h for weak TCs(including tropical storms and severe tropical storms at the initial time)and up to 24 h for strong TCs(including severe typhoons and super typhoons at the initial time).The effect of the initial vortex intensity correction is more important for developing TCs than for weakening TCs.

关键词： vortex intensity correction intensity bias intensity error tropical cyclones

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The Characteristics of Atmospheric Ice Nuclei Measured at Different Altitudes in the Huangshan Mountains in Southeast china

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Advances in Atmospheric Sciences 2014年第2期31卷 396-406页

作者： JIANG Hui YIN Yan YANG Lei YANG Shaozhong SU Hang CHEN Kui key laboratory for aerosol–cloud–precipitation of the china meteorological administration Nanjing University of Information Science and Technology Chinese Academy of meteorological Sciences key laboratory of meteorological Disaster of the Ministry of Education Nanjing University of Information Science and Technology

The concentration of ice nuclei （IN） and the relationship with aerosol particles were measured and analyzed using three 5-L mixing cloud chambers and a static diffusion cloud chamber at three altitudes in the Huangshan Mountains in Southeast china from May to September *** results showed that the mean total number concentration of IN on the highest peak of the Huangshan Mountains at an activation temperature （Ta） of-20℃C was 16.6 *** the supersaturation with respect to water （Sw） and with respect to ice （Si） were set to 5％,the average number concentrations of IN measured at an activation temperature of-20℃C by the static diffusion cloud chamber were 0.89 and 0.105 L-1,respectively.A comparison of the concentrations of IN at three different altitudes showed that the concentration of IN at the foot of the mountains was higher than at the peak.A further calculation of the correlation between IN and the concentrations of aerosol particles of different size ranges showed that the IN concentration was well correlated with the concentration of aerosol particles in the size range of 1.2-20 μ*** was also found that the IN concentration varied with meteorological conditions,such as wind speed,with higher IN concentrations often observed on days with strong *** analysis of the backward trajectories of air masses showed that low IN concentrations were often related to air masses travelling along southwest pathways,while higher IN concentrations were usually related to those transported along northeast pathways.

关键词： atmospheric ice nuclei mixing cloud chamber static diffusion cloud chamber deposition nucleation condensation freezing nucleation

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Evaluation of meteorological predictions by the WRF model at Barrow, Alaska and Summit, Greenland in the Arctic in April 2019

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Advances in Polar Science 2023年第4期34卷 352-367页

作者： ZHANG Tong CAO Le LI Simeng WANG Jiandong china meteorological administration aerosol-cloud-precipitation key laboratory Nanjing University of Information Science&TechnologyNanjing 210044China

Accurate meteorological predictions in the Arctic are important in response to the rapid climate change and insufficient meteorological observations in the *** this study,we adopted a high-resolution Weather Research and Forecasting(WRF)model to simulate the meteorology at two Arctic stations(Barrow and Summit)in April *** results were also evaluated by using surface measurements and statistical *** addition,weather charts during the studied time period were also used to assess the model *** results demonstrate that the WRF model is able to accurately capture the meteorological parameters for the two Arctic stations and the weather systems such as cyclones and anticyclones in the ***,we found the model performance in predicting the surface pressure the best while the performance in predicting the wind the worst among these meteorological ***,the wind predictions at these Arctic stations were found to be more accurate than those at urban stations in mid-latitude regions,due to the differences in land features and anthropogentic heat sources between these *** addition,a comparison of the simulation results showed that the prediction of meteorological conditions at Summit is superior to that at *** reasons for the deviations in temperature predictions between these two Arctic stations are uncertainties in the treatments of the sea ice and the cloud in the *** respect to the wind,the deviations may source from the overestimation of the wind over the sea and at coastal stations.

关键词： Arctic WRF meteorological parameters synoptic patterns model assessment

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