Surface ozone(O_(3))is a major air pollutant and draw increasing attention in the Pearl River Delta(PRD),China.Here,we characterize the spatial-temporal variability of ozone based on a dataset obtained from 57 nationa...Surface ozone(O_(3))is a major air pollutant and draw increasing attention in the Pearl River Delta(PRD),China.Here,we characterize the spatial-temporal variability of ozone based on a dataset obtained from 57 national monitoring sites during 2013-2019.Our results show that:(1)the seasonal difference of ozone distribution in the inland and coastal areas was significant,which was largely affected by the wind pattern reversals related to the East Asian monsoon,and local ozone production and destruction;(2)the daily maximum 8hr average(MDA8 O_(3))showed an overall upward trend by 1.11 ppbv/year.While the trends in the nine cities varied differently by ranging from-0.12 to 2.51 ppbv/year.The hot spots of ozone were spreading to southwestern areas from the central areas since 2016.And ozone is becoming a year-round air pollution problem with the pollution season extending to winter and spring in PRD region.(3)at the central and southwestern PRD cities,the percentage of exceedance days from the continuous type(defined as≥3 days)was increasing.Furthermore,the ozone concentration of continuous type was much higher than that of scattered exceedance type(<3 days).In addition,although the occurrence of continuous type starts to decline since2017,the total number of exceedance days during the continuous type is increasing.These results indicate that it is more difficult to eliminate the continuous exceedance than the scatter pollution days and highlight the great challenge in mitigation of O_(3)pollution in these cities.展开更多
Atmospheric boundary layer height(ABLH)is an important parameter used to depict characteristics of the planetary boundary layer(PBL)in the lower troposphere.The ABLH is strongly associated with the vertical distributi...Atmospheric boundary layer height(ABLH)is an important parameter used to depict characteristics of the planetary boundary layer(PBL)in the lower troposphere.The ABLH is strongly associated with the vertical distributions of heat,mass,and energy in the PBL,and it is a key quantity in numerical simulation of the PBL and plays an essential role in atmospheric environmental assessment.In this paper,various definitions and methods for deriving and estimating the ABLH are summarized,from the perspectives of turbulent motion,PBL dynamics and thermodynamics,and distributions of various substances in the PBL.Different methods for determining the ABLH by means of direct observation and remote sensing retrieval are reviewed,and comparisons of the advantages and disadvantages of these methods are presented.The paper also summarizes the ABLH parameterization schemes,discusses current problems in the estimation of ABLH,and finally points out the directions for possible future breakthroughs in the ABLHrelated research and application.展开更多
Quantification of the nonlinearities between ambient ozone(O3)and the emissions of nitrogen oxides(NOx)and volatile organic compound(VOC)is a prerequisite for an effective O3 control strategy.An Enhanced polynomial fu...Quantification of the nonlinearities between ambient ozone(O3)and the emissions of nitrogen oxides(NOx)and volatile organic compound(VOC)is a prerequisite for an effective O3 control strategy.An Enhanced polynomial functions Response Surface Model(Epf-RSM)with the capability to analyze O3-NOx-VOC sensitivities in real time was developed by integrating the hill-climbing adaptive method into the optimized Extended Response Surface Model(ERSM)system.The Epf-RSM could single out the best suited polynomial function for each grid cell to quantify the responses of O3 concentrations to precursor emission changes.Several comparisons between Epf-RSM and pf-ERSM(polynomial functions based ERSM)were performed using out-of-sample validation,together with comparisons of the spatial distribution and the Empirical Kinetic Modeling Approach diagrams.The comparison results showed that Epf-RSM effectively addressed the drawbacks of pf-ERSM with respect to overfitting in the margin areas and high biases in the transition areas.The O3 concentrations predicted by Epf-RSM agreed well with Community Multi-scale Air Quality simulation results.The case study results in the Pearl River Delta and the north-western area of the Shandong province indicated that the O3 formations in the central areas of both the regions were more sensitive to anthropogenic VOC in January,April,and October,while more NOx-sensitive in July.展开更多
基金supported by the Guangdong Major Project of Basic and Applied Basic Research (No.2020B0301030004)the National Natural Science Foundation of China (No.42175111)+1 种基金the Guangdong science and technology plan project (No.2019B121201002)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University (No.22qntd1908)。
文摘Surface ozone(O_(3))is a major air pollutant and draw increasing attention in the Pearl River Delta(PRD),China.Here,we characterize the spatial-temporal variability of ozone based on a dataset obtained from 57 national monitoring sites during 2013-2019.Our results show that:(1)the seasonal difference of ozone distribution in the inland and coastal areas was significant,which was largely affected by the wind pattern reversals related to the East Asian monsoon,and local ozone production and destruction;(2)the daily maximum 8hr average(MDA8 O_(3))showed an overall upward trend by 1.11 ppbv/year.While the trends in the nine cities varied differently by ranging from-0.12 to 2.51 ppbv/year.The hot spots of ozone were spreading to southwestern areas from the central areas since 2016.And ozone is becoming a year-round air pollution problem with the pollution season extending to winter and spring in PRD region.(3)at the central and southwestern PRD cities,the percentage of exceedance days from the continuous type(defined as≥3 days)was increasing.Furthermore,the ozone concentration of continuous type was much higher than that of scattered exceedance type(<3 days).In addition,although the occurrence of continuous type starts to decline since2017,the total number of exceedance days during the continuous type is increasing.These results indicate that it is more difficult to eliminate the continuous exceedance than the scatter pollution days and highlight the great challenge in mitigation of O_(3)pollution in these cities.
基金Supported by the National Key Research and Development Program of China(2016YFC0203300 and 2017YFC0209600)National Research Program for Key Issues in Air Pollution Control(DQGG0104 and DQGG0106)National Natural Science Foundation of China(91544216).
文摘Atmospheric boundary layer height(ABLH)is an important parameter used to depict characteristics of the planetary boundary layer(PBL)in the lower troposphere.The ABLH is strongly associated with the vertical distributions of heat,mass,and energy in the PBL,and it is a key quantity in numerical simulation of the PBL and plays an essential role in atmospheric environmental assessment.In this paper,various definitions and methods for deriving and estimating the ABLH are summarized,from the perspectives of turbulent motion,PBL dynamics and thermodynamics,and distributions of various substances in the PBL.Different methods for determining the ABLH by means of direct observation and remote sensing retrieval are reviewed,and comparisons of the advantages and disadvantages of these methods are presented.The paper also summarizes the ABLH parameterization schemes,discusses current problems in the estimation of ABLH,and finally points out the directions for possible future breakthroughs in the ABLHrelated research and application.
基金supported by the Science and Technology Program of Guangzhou,China(No.202002030188)the National Key Research and Development Program of China(No.2016YFC0207606)+2 种基金US EPA Emission,Air quality,and Meteorological Modeling Support(No.EP-D-12-044)the National Natural Science Foundation of China(Grant No.21625701),the Fundamental Research Funds for the Central Universities(Nos.D2160320,D6180330,and D2170150)the Natural Science Foundation of Guangdong Province,China(No.2017A030310279).
文摘Quantification of the nonlinearities between ambient ozone(O3)and the emissions of nitrogen oxides(NOx)and volatile organic compound(VOC)is a prerequisite for an effective O3 control strategy.An Enhanced polynomial functions Response Surface Model(Epf-RSM)with the capability to analyze O3-NOx-VOC sensitivities in real time was developed by integrating the hill-climbing adaptive method into the optimized Extended Response Surface Model(ERSM)system.The Epf-RSM could single out the best suited polynomial function for each grid cell to quantify the responses of O3 concentrations to precursor emission changes.Several comparisons between Epf-RSM and pf-ERSM(polynomial functions based ERSM)were performed using out-of-sample validation,together with comparisons of the spatial distribution and the Empirical Kinetic Modeling Approach diagrams.The comparison results showed that Epf-RSM effectively addressed the drawbacks of pf-ERSM with respect to overfitting in the margin areas and high biases in the transition areas.The O3 concentrations predicted by Epf-RSM agreed well with Community Multi-scale Air Quality simulation results.The case study results in the Pearl River Delta and the north-western area of the Shandong province indicated that the O3 formations in the central areas of both the regions were more sensitive to anthropogenic VOC in January,April,and October,while more NOx-sensitive in July.
