[Objective] The research aimed to analyze the rainstorm process and backward trajectory simulation of water vapor condition in Jilin Province in July,2010.[Method] Based on the actual situation data of routine weather...[Objective] The research aimed to analyze the rainstorm process and backward trajectory simulation of water vapor condition in Jilin Province in July,2010.[Method] Based on the actual situation data of routine weather chart,NCEP (2.5°×2.5°) reanalysis data per 6 h and GBL data of NOAA,the rainstorm process was carried out the diagnostic analysis of physical quantity in Jilin Province in July,2010.Moreover,HYSPLIT backward trajectory mode was used to simulate the water vapor source.[Result] The coexistence of upper-level divergence and low-level convergence generated the ascending motion,which was the dynamic condition of rainstorm appearance.The unstable energy induced by the low-level shear promoted the generation of heavy rainstorm.The water vapor source of precipitation process was divided into the water vapor in the southern sea area,northern high-altitude water vapor transportation and local water vapor source.[Conclusion] The research provided some reference basis for the forecast and analysis of rainstorm.展开更多
Using the observation data in Yongxing Island,South China Sea(SCS)from December 2013 to November 2018,the multiple time scales variation of atmospheric CO_(2)and CH_(4)were analyzed to understand their temporal variat...Using the observation data in Yongxing Island,South China Sea(SCS)from December 2013 to November 2018,the multiple time scales variation of atmospheric CO_(2)and CH_(4)were analyzed to understand their temporal variation characteristics and controlling factors.The regional-averaged background mole fractions of CO_(2)and CH_(4)both show a single-period sinusoidal variation with a lower value at noon and a higher value in the wee hours.In the seasonal scale,they exhibited a significant seasonal difference with higher values in winter and lower values in summer.In the annual scale,CO_(2)and CH_(4)both show an increasing trend,with an annual growth rate of approximately 3.2 ppm and 12 ppb,respectively.The annual growth rate at this site was higher than the global average.The change in atmospheric CO_(2)and CH_(4)in Yongxing Island was probably caused by the higher emission of the surrounding areas and the airflows driven by monsoon.Hopefully,the long-term and high-resolution greenhouse gases(GHGs)dataset will aid relevent researchers and decision-makers in performing more in-depth studies for GHG sources in order to derive effective strategies.展开更多
Synoptic patterns identified by an automated procedure employing principal- component analysis and a two-stage cluster analysis, and backward trajectory analysis clustered by the HYSPLIT4.9 model were used to examine ...Synoptic patterns identified by an automated procedure employing principal- component analysis and a two-stage cluster analysis, and backward trajectory analysis clustered by the HYSPLIT4.9 model were used to examine air quality patterns over¨ Uru¨mqi, China, one of the most heavily polluted cities in the world. Six synoptic patterns representing different atmospheric circulation patterns and air-mass characteristics were classified during the winter heating periods from 2001 to 2008, and seven trajectory clusters representing different paths of air masses arriving at ürümqi were calculated during the winter heating periods from 2005 to 2008. Then air quality was evaluated using these two approaches, and significant variations were found across both synoptic patterns and trajectory clusters. The heaviest air-pollution episodes occurred when ürümqi was either in an extremely cold, strong anticyclone or at the front of a migrating cyclone. Both conditions were characterized by with light winds, cold, wet surface air, and relatively dry upper air. ürümqi was predominately influenced by air masses from the southwest and from local areas. Air pollution index (API) levels were highest for air masses originating from the southwest with a longer path or for the local area, because of transport from semi-desert/desert regions by strong winds and because of local heavy pollution emissions, respectively. The interactions between these two analytical approaches showed that poor diffusion conditions, together with local circulation, enhanced air pollution, besides, regional air-mass transport caused by strong winds contributed to serious air quality under relatively good diffusion conditions.展开更多
The first generation of the oriental armyworm, Mythimna separata(Walker), arrives every year in northern Japan in mainly late May to early June. Analyses of weather maps suggested that this moth’s immigration source ...The first generation of the oriental armyworm, Mythimna separata(Walker), arrives every year in northern Japan in mainly late May to early June. Analyses of weather maps suggested that this moth’s immigration source could be eastern China, but the accuracy of those analyses was very limited due to the lack of a current standard trajectory analysis. The management of migratory insect pests such as M. separata benefits from the identification of the migration source(s)and pathway(s) of the pests. The present study provides a trajectory analysis for M. separata. Backward trajectories from trap sites in northern Japan were calculated with the HYSPLIT System developed by the U.S. National Oceanic and Atmospheric Administration, taking the flight speed of M. separata and the limitation of low ambient temperature at flight height into account. The ending times of the moth’s short and long trajectories were set at dusk on the day before and two days before the possible arrival date, respectively. The results suggested two types of possible migration pathway: a multi-step pathway from Northeast China, the Korean Peninsula, and eastern Russia, which are destination areas of the first-generation’s migration, and a direct pathway from seasonal main emigration areas in eastern China such as Jiangsu and Shandong provinces. These findings contribute to our understanding of the migration ecology of M. separata and can be used for the development of methods to predict the migration of this insect.展开更多
This study analyzed the spatio-temporal variability of air quality data for six standard air pollutants(Particulate Matter 2.5(PM2.5),Particulate Matter 10(PM10),SO2,NO2,CO,and O3)in the Sichuan Basin(SCB),China from ...This study analyzed the spatio-temporal variability of air quality data for six standard air pollutants(Particulate Matter 2.5(PM2.5),Particulate Matter 10(PM10),SO2,NO2,CO,and O3)in the Sichuan Basin(SCB),China from 2015 to 2018 in relation to the formation of haze using conventional meteorological data(temperature,wind speed,and relative humidity),satellite data(fire point data,vertical profiles of aerosol subtypes,and aerosol optical depth),planetary boundary layer height,and backward trajectories.The results indicated that the spatio-temporal evolution of the air quality index(AQI)had notable seasonality for the pollution severity in descending order:winter,spring,summer,and autumn.Autumn and winter severe haze events occurred in November and January,respectively,and were caused by higher local pollution emissions under stagnant air conditions.Spring severe haze events occurred in May and were caused by dust from Northwest China and local regions.Severe summer haze events occurred in July and were caused by local burning.Therefore,the analyses showed that local burning,stagnant meteorological conditions,air mass transport and anthropogenic pollution emissions played a key role in haze in the SCB.This study provides scientific insights for fully analyzing heavy air pollution in SCB,China,and also provides a scientific basis for pollution research in regions of complex terrain as basins and mountains.展开更多
Trace metals associated with PM_(10) aerosols and their variation during day and nighttime as well as during different seasons have been studied for the year 2012. PCA analysis suggested5 PCs,which accounted for 86.8%...Trace metals associated with PM_(10) aerosols and their variation during day and nighttime as well as during different seasons have been studied for the year 2012. PCA analysis suggested5 PCs,which accounted for 86.8% cumulative variance. PC1 accounted for 30% with a significant loading of metals of anthropogenic origin,while PC2 showed 28% variance with the loading of metals of crustal origin. These trace metals showed seasonal distinct day and night time characteristics. The concentrations of Cu,Pb,and Cd were found to be higher during nighttime in all the seasons. Only Fe was observed with significantly higher mean concentrations during daytime of all seasons except monsoon. The highest mean values of Cu,Cd,Zn,and Pb during post-monsoon might be attributed to winds advection over the regions of waste/biomass burning and industrial activities in Punjab and Haryana regions.Furthermore,concentration weighted trajectory analysis suggested that metals of crustal origin were contributed by long-range transport while metals of anthropogenic and industrial activities were contributed by regional/local source regions.展开更多
Based on one-year observation,the concentration,sources,and potential source areas of volatile organic compounds(VOCs)were comprehensively analyzed to investigate the pollution characteristics of ambient VOCs in Haiko...Based on one-year observation,the concentration,sources,and potential source areas of volatile organic compounds(VOCs)were comprehensively analyzed to investigate the pollution characteristics of ambient VOCs in Haikou,China.The results showed that the annual average concentration of total VOCs(TVOCs)was 11.4 ppb V,and the composition was dominated by alkanes(8.2 ppb V,71.4%)and alkenes(1.3 ppb V,20.5%).The diurnal variation in the concentration of dominant VOC species showed a distinct bimodal distribution with peaks in the morning and evening.The greatest contribution to ozone formation potential(OFP)was made by alkenes(51.6%),followed by alkanes(27.2%).The concentrations of VOCs and nitrogen dioxide(NO_(2))in spring and summer were low,and it was difficult to generate high ozone(O_(3))concentrations through photochemical reactions.The significant increase in O_(3)concentrations in autumn and winter was mainly related to the transmission of pollutants from the northeast.Traffic sources(40.1%),industrial sources(19.4%),combustion sources(18.6%),solvent usage sources(15.5%)and plant sources(6.4%)were identified as major sources of VOCs through the positive matrix factorization(PMF)model.The southeastern coastal areas of China were identified as major potential source areas of VOCs through the potential source contribution function(PSCF)and concentration-weighted trajectory(CWT)models.Overall,the concentration of ambient VOCs in Haikou was strongly influenced by traffic sources and long-distance transport,and the control of VOCs emitted from vehicles should be strengthened to reduce the active species of ambient VOCs in Haikou,thereby reducing the generation of O_(3).展开更多
To better understand the characteristics and sources of water soluble ions(WSI) in North China Plain(NCP),fine particles(PM2.5) were simultaneously sampled at the summit(SM)and foot(FT) of Mount Tai during May 12th to...To better understand the characteristics and sources of water soluble ions(WSI) in North China Plain(NCP),fine particles(PM2.5) were simultaneously sampled at the summit(SM)and foot(FT) of Mount Tai during May 12th to June 24th,2017.Ion chromato graphy analysis showed that concentration of WSI was lower at SM(22.26±16.53 μg/m3) than that at FT(31.02±21.92 μg/m3).The concentration and proportion of SO4^2- in total WSI were both lower than the values reported in previous studies.Daytime WSI concentrations were higher than that at nighttime at SM,while the opposite results were obtained at FT,possibly associated with more anthropogenic activities and higher boundary layer height(BLH) during daytimes.A severe pollution event occurred during June 14 th-June 16th was documented at both FT and SM.Regional transport and topography-forced vertical transport along the slope of the mountain could explain the higher concentrations of pollutants at SM.The analyses also indicated that NH4^+ existed mainly in the form of NH4 HSO4 and NH4 NO3,but(NH4)2 SO4 could also exist,especially when emissions of NH4 and NH3 were increased during daytime at FT.The results of principal component analysis(PCA) illustrated that secondary aerosols,coal/biomass burnings,sea-salts and crustal/soil dusts were the main sources at SM,and secondary aerosols and crustal/soil dusts contributed most at FT.Backward air-mass trajectories were classified into four clusters,of which air masses with the highest frequency and WSI concentrations were originated from the southwest with secondary ions(SO4^2-,NO3-and NH4^+) as major pollutants.展开更多
文摘[Objective] The research aimed to analyze the rainstorm process and backward trajectory simulation of water vapor condition in Jilin Province in July,2010.[Method] Based on the actual situation data of routine weather chart,NCEP (2.5°×2.5°) reanalysis data per 6 h and GBL data of NOAA,the rainstorm process was carried out the diagnostic analysis of physical quantity in Jilin Province in July,2010.Moreover,HYSPLIT backward trajectory mode was used to simulate the water vapor source.[Result] The coexistence of upper-level divergence and low-level convergence generated the ascending motion,which was the dynamic condition of rainstorm appearance.The unstable energy induced by the low-level shear promoted the generation of heavy rainstorm.The water vapor source of precipitation process was divided into the water vapor in the southern sea area,northern high-altitude water vapor transportation and local water vapor source.[Conclusion] The research provided some reference basis for the forecast and analysis of rainstorm.
基金supported by the National Natural Science Foundation of China(No.41907180).
文摘Using the observation data in Yongxing Island,South China Sea(SCS)from December 2013 to November 2018,the multiple time scales variation of atmospheric CO_(2)and CH_(4)were analyzed to understand their temporal variation characteristics and controlling factors.The regional-averaged background mole fractions of CO_(2)and CH_(4)both show a single-period sinusoidal variation with a lower value at noon and a higher value in the wee hours.In the seasonal scale,they exhibited a significant seasonal difference with higher values in winter and lower values in summer.In the annual scale,CO_(2)and CH_(4)both show an increasing trend,with an annual growth rate of approximately 3.2 ppm and 12 ppb,respectively.The annual growth rate at this site was higher than the global average.The change in atmospheric CO_(2)and CH_(4)in Yongxing Island was probably caused by the higher emission of the surrounding areas and the airflows driven by monsoon.Hopefully,the long-term and high-resolution greenhouse gases(GHGs)dataset will aid relevent researchers and decision-makers in performing more in-depth studies for GHG sources in order to derive effective strategies.
基金supported by the National Basic Research Program (also called 973 Program) of China (Grant No 2007CB407303)the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No KZCX2-YW-Q02-03)
文摘Synoptic patterns identified by an automated procedure employing principal- component analysis and a two-stage cluster analysis, and backward trajectory analysis clustered by the HYSPLIT4.9 model were used to examine air quality patterns over¨ Uru¨mqi, China, one of the most heavily polluted cities in the world. Six synoptic patterns representing different atmospheric circulation patterns and air-mass characteristics were classified during the winter heating periods from 2001 to 2008, and seven trajectory clusters representing different paths of air masses arriving at ürümqi were calculated during the winter heating periods from 2005 to 2008. Then air quality was evaluated using these two approaches, and significant variations were found across both synoptic patterns and trajectory clusters. The heaviest air-pollution episodes occurred when ürümqi was either in an extremely cold, strong anticyclone or at the front of a migrating cyclone. Both conditions were characterized by with light winds, cold, wet surface air, and relatively dry upper air. ürümqi was predominately influenced by air masses from the southwest and from local areas. Air pollution index (API) levels were highest for air masses originating from the southwest with a longer path or for the local area, because of transport from semi-desert/desert regions by strong winds and because of local heavy pollution emissions, respectively. The interactions between these two analytical approaches showed that poor diffusion conditions, together with local circulation, enhanced air pollution, besides, regional air-mass transport caused by strong winds contributed to serious air quality under relatively good diffusion conditions.
基金supported by the Strategic International Collaborative Research Project promoted by the Ministry of Agriculture, Forestry and Fisheries, Tokyo, Japan (JPJ008837)。
文摘The first generation of the oriental armyworm, Mythimna separata(Walker), arrives every year in northern Japan in mainly late May to early June. Analyses of weather maps suggested that this moth’s immigration source could be eastern China, but the accuracy of those analyses was very limited due to the lack of a current standard trajectory analysis. The management of migratory insect pests such as M. separata benefits from the identification of the migration source(s)and pathway(s) of the pests. The present study provides a trajectory analysis for M. separata. Backward trajectories from trap sites in northern Japan were calculated with the HYSPLIT System developed by the U.S. National Oceanic and Atmospheric Administration, taking the flight speed of M. separata and the limitation of low ambient temperature at flight height into account. The ending times of the moth’s short and long trajectories were set at dusk on the day before and two days before the possible arrival date, respectively. The results suggested two types of possible migration pathway: a multi-step pathway from Northeast China, the Korean Peninsula, and eastern Russia, which are destination areas of the first-generation’s migration, and a direct pathway from seasonal main emigration areas in eastern China such as Jiangsu and Shandong provinces. These findings contribute to our understanding of the migration ecology of M. separata and can be used for the development of methods to predict the migration of this insect.
基金Under the auspices of National Key R&D Program of China(No.2017YFC0601505)National Natural Science Foundation of China(No.41672325,41602334)Opening Fund of Geomathematics Key Laboratory of Sichuan Province(scsxdz2019zd01)。
文摘This study analyzed the spatio-temporal variability of air quality data for six standard air pollutants(Particulate Matter 2.5(PM2.5),Particulate Matter 10(PM10),SO2,NO2,CO,and O3)in the Sichuan Basin(SCB),China from 2015 to 2018 in relation to the formation of haze using conventional meteorological data(temperature,wind speed,and relative humidity),satellite data(fire point data,vertical profiles of aerosol subtypes,and aerosol optical depth),planetary boundary layer height,and backward trajectories.The results indicated that the spatio-temporal evolution of the air quality index(AQI)had notable seasonality for the pollution severity in descending order:winter,spring,summer,and autumn.Autumn and winter severe haze events occurred in November and January,respectively,and were caused by higher local pollution emissions under stagnant air conditions.Spring severe haze events occurred in May and were caused by dust from Northwest China and local regions.Severe summer haze events occurred in July and were caused by local burning.Therefore,the analyses showed that local burning,stagnant meteorological conditions,air mass transport and anthropogenic pollution emissions played a key role in haze in the SCB.This study provides scientific insights for fully analyzing heavy air pollution in SCB,China,and also provides a scientific basis for pollution research in regions of complex terrain as basins and mountains.
基金Partial financial support from the CSIR network project(PSC 0112)CSIR fellowship to Subhash Chandra,SRF
文摘Trace metals associated with PM_(10) aerosols and their variation during day and nighttime as well as during different seasons have been studied for the year 2012. PCA analysis suggested5 PCs,which accounted for 86.8% cumulative variance. PC1 accounted for 30% with a significant loading of metals of anthropogenic origin,while PC2 showed 28% variance with the loading of metals of crustal origin. These trace metals showed seasonal distinct day and night time characteristics. The concentrations of Cu,Pb,and Cd were found to be higher during nighttime in all the seasons. Only Fe was observed with significantly higher mean concentrations during daytime of all seasons except monsoon. The highest mean values of Cu,Cd,Zn,and Pb during post-monsoon might be attributed to winds advection over the regions of waste/biomass burning and industrial activities in Punjab and Haryana regions.Furthermore,concentration weighted trajectory analysis suggested that metals of crustal origin were contributed by long-range transport while metals of anthropogenic and industrial activities were contributed by regional/local source regions.
基金supported by the Major Program of Science and Technology of Hainan Province,China(No.ZDKJ202007)the Special Foundation of Government Financial of Hainan Province,China(No.ZC2018-196)the Youth Innovation Foundation of Hainan Research Academy of Environmental Sciences,China(No.QNCX2021002)。
文摘Based on one-year observation,the concentration,sources,and potential source areas of volatile organic compounds(VOCs)were comprehensively analyzed to investigate the pollution characteristics of ambient VOCs in Haikou,China.The results showed that the annual average concentration of total VOCs(TVOCs)was 11.4 ppb V,and the composition was dominated by alkanes(8.2 ppb V,71.4%)and alkenes(1.3 ppb V,20.5%).The diurnal variation in the concentration of dominant VOC species showed a distinct bimodal distribution with peaks in the morning and evening.The greatest contribution to ozone formation potential(OFP)was made by alkenes(51.6%),followed by alkanes(27.2%).The concentrations of VOCs and nitrogen dioxide(NO_(2))in spring and summer were low,and it was difficult to generate high ozone(O_(3))concentrations through photochemical reactions.The significant increase in O_(3)concentrations in autumn and winter was mainly related to the transmission of pollutants from the northeast.Traffic sources(40.1%),industrial sources(19.4%),combustion sources(18.6%),solvent usage sources(15.5%)and plant sources(6.4%)were identified as major sources of VOCs through the positive matrix factorization(PMF)model.The southeastern coastal areas of China were identified as major potential source areas of VOCs through the potential source contribution function(PSCF)and concentration-weighted trajectory(CWT)models.Overall,the concentration of ambient VOCs in Haikou was strongly influenced by traffic sources and long-distance transport,and the control of VOCs emitted from vehicles should be strengthened to reduce the active species of ambient VOCs in Haikou,thereby reducing the generation of O_(3).
基金supported by the National Natural Science Foundation of China(Nos.41590873,41575132,and 91644224)。
文摘To better understand the characteristics and sources of water soluble ions(WSI) in North China Plain(NCP),fine particles(PM2.5) were simultaneously sampled at the summit(SM)and foot(FT) of Mount Tai during May 12th to June 24th,2017.Ion chromato graphy analysis showed that concentration of WSI was lower at SM(22.26±16.53 μg/m3) than that at FT(31.02±21.92 μg/m3).The concentration and proportion of SO4^2- in total WSI were both lower than the values reported in previous studies.Daytime WSI concentrations were higher than that at nighttime at SM,while the opposite results were obtained at FT,possibly associated with more anthropogenic activities and higher boundary layer height(BLH) during daytimes.A severe pollution event occurred during June 14 th-June 16th was documented at both FT and SM.Regional transport and topography-forced vertical transport along the slope of the mountain could explain the higher concentrations of pollutants at SM.The analyses also indicated that NH4^+ existed mainly in the form of NH4 HSO4 and NH4 NO3,but(NH4)2 SO4 could also exist,especially when emissions of NH4 and NH3 were increased during daytime at FT.The results of principal component analysis(PCA) illustrated that secondary aerosols,coal/biomass burnings,sea-salts and crustal/soil dusts were the main sources at SM,and secondary aerosols and crustal/soil dusts contributed most at FT.Backward air-mass trajectories were classified into four clusters,of which air masses with the highest frequency and WSI concentrations were originated from the southwest with secondary ions(SO4^2-,NO3-and NH4^+) as major pollutants.
