Trace metals associated with PM10 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% cu...Trace metals associated with PM10 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 splitting multi-symplectic structures, a new multi-symplectic scheme is proposed and applied to a nonlinear wave equation. The explicit multi-symplectic scheme of the nonlinear wave equation is obtained, and ...Based on splitting multi-symplectic structures, a new multi-symplectic scheme is proposed and applied to a nonlinear wave equation. The explicit multi-symplectic scheme of the nonlinear wave equation is obtained, and the corresponding multi-symplectic conservation property is proved. The backward error analysis shows that the explicit multi-symplectic scheme has good accuracy. The sine-Gordon equation and the Klein-Gordon equation are simulated by an explicit multi-symplectic scheme. The numerical results show that the new explicit multi-symplectic scheme can well simulate the solitary wave behaviors of the nonlinear wave equation and approximately preserve the relative energy error of the equation.展开更多
In order to evaluate seasonal and regional variations in precipitation in Niigata City, 65 hourly precipitation samples were collected from October 2009 to June 2011 including two snow events. In this work, major ions...In order to evaluate seasonal and regional variations in precipitation in Niigata City, 65 hourly precipitation samples were collected from October 2009 to June 2011 including two snow events. In this work, major ions （Na＋, K＋, Ca2＋, Mg2＋, NH4＋, SO4^2-, NO3- and Cl-） were combined with tritium （^3H or T） concentration （T specific activity） in both precipitation and snow, and transformation patterns of polluted air mass in Niigata region were revealed. The low level tritium in precipitation was measured by a distillation process and an electrolytic enrichment process. Each tritium concentration in the precipitation sample thus obtained was measured by liquid scintillation counter. On the basis of the above measurement and analysis, it was found that the tritium and nss （non-sea-salt） calcium concentrations showed a seasonal variation with a highest value in spring over one year.展开更多
Time-course of oxygen stable isotopic ratios （i.e., δ^18O） as well as seasonal variation of δ^18O has been examined to investigate the characteristics, sources and the passing route of precipitations in Niigata Pr...Time-course of oxygen stable isotopic ratios （i.e., δ^18O） as well as seasonal variation of δ^18O has been examined to investigate the characteristics, sources and the passing route of precipitations in Niigata Prefecture. The precipitation samples have been mainly collected with a filtrating bulk sampler at the rooftop of Niigata University. Furthermore, backward trajectories analyses have been also conducted for these samples taken sequentially for a short period. Consequently, the following features have been mainly clarified for the precipitations in Niigata Prefecture： （1） the δ^18O values varied between -14.57%o and -3.86%0 in the precipitations of Niigata University; （2） as for the comparison among sampling points, the mean value of δ^18O at seaside spots （i.e., Niigata City： -6.93%0） is larger than that of inland spots （Sanjyo City： -8.68%0）; （3） δ^18O value was generally small in the rainy or typhoon season, and relatively large in summer; （4） decreasing δ^18O content with time is a predominant feature of sequentially sampled rainfalls as predicted by Rayleigh models of atmospheric vapor condensation.展开更多
Dry deposition velocities and fluxes of PM10 during Asian dust events over the Yellow Sea from 2001 to 2007 were investigated using observation data in Qingdao, China and Jeju, Korea. The dry deposition velocities of ...Dry deposition velocities and fluxes of PM10 during Asian dust events over the Yellow Sea from 2001 to 2007 were investigated using observation data in Qingdao, China and Jeju, Korea. The dry deposition velocities of PM 10 during dust events over the Yellow Sea ranged from 0.19 to 8.17 cm/sec, with an average of 3.38 cm/sec. Dry deposition fluxes of PM10 during dust events over the Yellow Sea were in the range of 68.5-2647.1 mg/（m2.day）, with an average of 545.4 mg/（m2.day）, which is 2-10 times higher than those reported by other studies for both dust and non-dust periods. It was estimated that 2.6× 10^11-48.7 × 10^11 g dust particles deposit to the Yellow Sea during dust events through dry deposition every year. Compared with the results in previous studies, it was found that the dry deposition of PM10 over the Yellow Sea during dust events in the years with high frequency of dust could account for a large or overwhelming fraction of the annual total dry deposition. Backward air mass trajectory analysis showed that dust events influenced Jeju mainly originated from the desert regions located in Mongolia and Inner Mongolia, China. There were 119 backward trajectories influenced both Qingdao and Jeju during 15 dust events from 2001 to 2007, accounting for 61.3% of the total trajectories of 194, indicating that Qingdao and Jeju were usually on the same pathway of dust transport downwind from source areas.展开更多
Presents a study that analyzed the symplecticness, stability and asymptotic of Runge-Kutta, partitioned Runge-Kutta, and Runge-Kutta-Nystr ? m methods applied to linear Hamiltonian systems. Numerical representation of...Presents a study that analyzed the symplecticness, stability and asymptotic of Runge-Kutta, partitioned Runge-Kutta, and Runge-Kutta-Nystr ? m methods applied to linear Hamiltonian systems. Numerical representation of the problem; Results in connection to P-stability; Details of the application of backward error analysis in the study.展开更多
Understanding and mitigating PM_(2.5)and ozone(O_(3))pollution remains challenging due to the nonlinear atmospheric chemistry and spatially heterogeneous nature of pollutant emissions.Traditional forward modeling appr...Understanding and mitigating PM_(2.5)and ozone(O_(3))pollution remains challenging due to the nonlinear atmospheric chemistry and spatially heterogeneous nature of pollutant emissions.Traditional forward modeling approaches suffer from high computational cost and limited diagnostic resolution to precisely attribute emissions sources at fine spatial,temporal,and chemical scales.Adjoint modeling has emerged as an efficient alternative,enabling high-resolution,multi-pollutant source attribution in a single integrated framework;however,its application to simultaneous PM_(2.5)-O_(3)pollution episodes is limited,particularly in densely populated regions experiencing complex co-pollutant interactions.Here we apply a newly developed multiphase adjoint of the Community Multiscale Air Quality(CMAQ)model to quantify the emission sensitivities of PM_(2.5)and O_(3)concentrations during pollution episodes in major urban agglomerations.Our results indicate that local emissions predominantly drive PM_(2.5)concentrations,contributing up to 79μg m^(-3).In contrast,O_(3)episodes are largely initiated by regional transport(3.8-7.3 ppbv),surpassing local emission contributions during episode onset.The sensitivity analyses reveal distinct spatial emission signatures and pollutant-specific influences from critical precursors,including volatile organic compounds(VOCs;up to 15.9 ppbv O_(3),11.4μg m^(-3)PM_(2.5)),nitrogen oxides(NO_(x);16.6 ppbv O_(3),13.8μg m^(-3)PM_(2.5)),and ammonia(NH_(3);up to 8.7μg m^(-3)PM_(2.5)).This study demonstrates the diagnostic strength and predictive capabilities of adjoint modeling in unraveling complex source-receptor relationships.By offering detailed,pollutant-specific emission sensitivity information,our approach provides a robust foundation for precision-driven emission control strategies and improved cross-regional policy coordination,substantially advancing air quality management frameworks.展开更多
A newscheme for the Zakharov-Kuznetsov(ZK)equationwith the accuracy order of O(△t^(2)+△x+△y^(2))is proposed.The multi-symplectic conservation property of the new scheme is proved.The backward error analysis of the ...A newscheme for the Zakharov-Kuznetsov(ZK)equationwith the accuracy order of O(△t^(2)+△x+△y^(2))is proposed.The multi-symplectic conservation property of the new scheme is proved.The backward error analysis of the newmulti-symplectic scheme is also implemented.The solitary wave evolution behaviors of the Zakharov-Kunetsov equation is investigated by the new multi-symplectic scheme.The accuracy of the scheme is analyzed.展开更多
In this paper, we study structure-preserving algorithms for dynamical systems defined by ordinary differential equations in R^n The equations are assumed to be of the form y^· = A（y） ＋ D（y） ＋ R（y）, where ...In this paper, we study structure-preserving algorithms for dynamical systems defined by ordinary differential equations in R^n The equations are assumed to be of the form y^· = A（y） ＋ D（y） ＋ R（y）, where A（y） is the conservative part subject to （A（y）, y） = 0; D（y） is the damping part or the part describing the coexistence of damping and expanding; R（y） reflects strange phenomenon of the system. It is shown that the numerical solutions generated by the symplectic Runge-Kutta（SRK） methods with bi 〉 0 （ i = 1,..., s） have long-time approximations to the exact ones, and these methods can describe the structural properties of the quadratic energy for these systems. Some numerical experiments and backward error analysis also show that these methods are better than other methods including the general algebraically stable Runge-Kutta（RK）methods.展开更多
基金Partial financial support from the CSIR network project(PSC 0112)CSIR fellowship to Subhash Chandra,SRF
文摘Trace metals associated with PM10 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Project supported by the National Natural Science Foundation of China(Nos.11161017,11071251,and 10871099)the National Basic Research Program of China(973 Program)(No.2007CB209603)+1 种基金the Natural Science Foundation of Hainan Province(No.110002)the Scientific Research Foun-dation of Hainan University(No.kyqd1053)
文摘Based on splitting multi-symplectic structures, a new multi-symplectic scheme is proposed and applied to a nonlinear wave equation. The explicit multi-symplectic scheme of the nonlinear wave equation is obtained, and the corresponding multi-symplectic conservation property is proved. The backward error analysis shows that the explicit multi-symplectic scheme has good accuracy. The sine-Gordon equation and the Klein-Gordon equation are simulated by an explicit multi-symplectic scheme. The numerical results show that the new explicit multi-symplectic scheme can well simulate the solitary wave behaviors of the nonlinear wave equation and approximately preserve the relative energy error of the equation.
文摘In order to evaluate seasonal and regional variations in precipitation in Niigata City, 65 hourly precipitation samples were collected from October 2009 to June 2011 including two snow events. In this work, major ions （Na＋, K＋, Ca2＋, Mg2＋, NH4＋, SO4^2-, NO3- and Cl-） were combined with tritium （^3H or T） concentration （T specific activity） in both precipitation and snow, and transformation patterns of polluted air mass in Niigata region were revealed. The low level tritium in precipitation was measured by a distillation process and an electrolytic enrichment process. Each tritium concentration in the precipitation sample thus obtained was measured by liquid scintillation counter. On the basis of the above measurement and analysis, it was found that the tritium and nss （non-sea-salt） calcium concentrations showed a seasonal variation with a highest value in spring over one year.
文摘Time-course of oxygen stable isotopic ratios （i.e., δ^18O） as well as seasonal variation of δ^18O has been examined to investigate the characteristics, sources and the passing route of precipitations in Niigata Prefecture. The precipitation samples have been mainly collected with a filtrating bulk sampler at the rooftop of Niigata University. Furthermore, backward trajectories analyses have been also conducted for these samples taken sequentially for a short period. Consequently, the following features have been mainly clarified for the precipitations in Niigata Prefecture： （1） the δ^18O values varied between -14.57%o and -3.86%0 in the precipitations of Niigata University; （2） as for the comparison among sampling points, the mean value of δ^18O at seaside spots （i.e., Niigata City： -6.93%0） is larger than that of inland spots （Sanjyo City： -8.68%0）; （3） δ^18O value was generally small in the rainy or typhoon season, and relatively large in summer; （4） decreasing δ^18O content with time is a predominant feature of sequentially sampled rainfalls as predicted by Rayleigh models of atmospheric vapor condensation.
基金supportedby the National Nature Science Foundation of China(No.40976063)the Sino-Japan Joint Project(No.2010DFA91350)+1 种基金the China Postdoctoral Science Foundation(No.2012M511548)the Fundamental Research Funds for the Central Universities(No.201213008)
文摘Dry deposition velocities and fluxes of PM10 during Asian dust events over the Yellow Sea from 2001 to 2007 were investigated using observation data in Qingdao, China and Jeju, Korea. The dry deposition velocities of PM 10 during dust events over the Yellow Sea ranged from 0.19 to 8.17 cm/sec, with an average of 3.38 cm/sec. Dry deposition fluxes of PM10 during dust events over the Yellow Sea were in the range of 68.5-2647.1 mg/（m2.day）, with an average of 545.4 mg/（m2.day）, which is 2-10 times higher than those reported by other studies for both dust and non-dust periods. It was estimated that 2.6× 10^11-48.7 × 10^11 g dust particles deposit to the Yellow Sea during dust events through dry deposition every year. Compared with the results in previous studies, it was found that the dry deposition of PM10 over the Yellow Sea during dust events in the years with high frequency of dust could account for a large or overwhelming fraction of the annual total dry deposition. Backward air mass trajectory analysis showed that dust events influenced Jeju mainly originated from the desert regions located in Mongolia and Inner Mongolia, China. There were 119 backward trajectories influenced both Qingdao and Jeju during 15 dust events from 2001 to 2007, accounting for 61.3% of the total trajectories of 194, indicating that Qingdao and Jeju were usually on the same pathway of dust transport downwind from source areas.
文摘Presents a study that analyzed the symplecticness, stability and asymptotic of Runge-Kutta, partitioned Runge-Kutta, and Runge-Kutta-Nystr ? m methods applied to linear Hamiltonian systems. Numerical representation of the problem; Results in connection to P-stability; Details of the application of backward error analysis in the study.
基金supported by the National Natural Science Foundation of China(42475108)the Ministry of Science and Technology of the People's Republic of China(2023YFE0112901)+5 种基金Shenzhen Science and Technology Program(KQTD20240729102048052)the National Natural Science Foundation of China(42192512 and 42207116)the Shenzhen Key Laboratory of Precision Measurement and Early Warning Technology for Urban Environmental Health Risks(ZDSYS20220606100604008)Shenzhen Science and Technology Program(JCYJ20241202152804007 and JCYJ20220818100611024)High-level University Special Fund(G03034K006)Center for Computational Science and Engineering at Southern University of Science and Technology.
文摘Understanding and mitigating PM_(2.5)and ozone(O_(3))pollution remains challenging due to the nonlinear atmospheric chemistry and spatially heterogeneous nature of pollutant emissions.Traditional forward modeling approaches suffer from high computational cost and limited diagnostic resolution to precisely attribute emissions sources at fine spatial,temporal,and chemical scales.Adjoint modeling has emerged as an efficient alternative,enabling high-resolution,multi-pollutant source attribution in a single integrated framework;however,its application to simultaneous PM_(2.5)-O_(3)pollution episodes is limited,particularly in densely populated regions experiencing complex co-pollutant interactions.Here we apply a newly developed multiphase adjoint of the Community Multiscale Air Quality(CMAQ)model to quantify the emission sensitivities of PM_(2.5)and O_(3)concentrations during pollution episodes in major urban agglomerations.Our results indicate that local emissions predominantly drive PM_(2.5)concentrations,contributing up to 79μg m^(-3).In contrast,O_(3)episodes are largely initiated by regional transport(3.8-7.3 ppbv),surpassing local emission contributions during episode onset.The sensitivity analyses reveal distinct spatial emission signatures and pollutant-specific influences from critical precursors,including volatile organic compounds(VOCs;up to 15.9 ppbv O_(3),11.4μg m^(-3)PM_(2.5)),nitrogen oxides(NO_(x);16.6 ppbv O_(3),13.8μg m^(-3)PM_(2.5)),and ammonia(NH_(3);up to 8.7μg m^(-3)PM_(2.5)).This study demonstrates the diagnostic strength and predictive capabilities of adjoint modeling in unraveling complex source-receptor relationships.By offering detailed,pollutant-specific emission sensitivity information,our approach provides a robust foundation for precision-driven emission control strategies and improved cross-regional policy coordination,substantially advancing air quality management frameworks.
基金supported by the National Natural Science Foundation of China(No.11161017,11071251 and 11271195)the Natural Science Foundation of Hainan Province(114003)the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘A newscheme for the Zakharov-Kuznetsov(ZK)equationwith the accuracy order of O(△t^(2)+△x+△y^(2))is proposed.The multi-symplectic conservation property of the new scheme is proved.The backward error analysis of the newmulti-symplectic scheme is also implemented.The solitary wave evolution behaviors of the Zakharov-Kunetsov equation is investigated by the new multi-symplectic scheme.The accuracy of the scheme is analyzed.
文摘In this paper, we study structure-preserving algorithms for dynamical systems defined by ordinary differential equations in R^n The equations are assumed to be of the form y^· = A（y） ＋ D（y） ＋ R（y）, where A（y） is the conservative part subject to （A（y）, y） = 0; D（y） is the damping part or the part describing the coexistence of damping and expanding; R（y） reflects strange phenomenon of the system. It is shown that the numerical solutions generated by the symplectic Runge-Kutta（SRK） methods with bi 〉 0 （ i = 1,..., s） have long-time approximations to the exact ones, and these methods can describe the structural properties of the quadratic energy for these systems. Some numerical experiments and backward error analysis also show that these methods are better than other methods including the general algebraically stable Runge-Kutta（RK）methods.
