Wuhan Tianhe International Airport (WUH) was suspended to contain the spread of COVID-19,while Shanghai Hongqiao International Airport (SHA) saw a tremendousflight reduction.Closure of a major international airport is...Wuhan Tianhe International Airport (WUH) was suspended to contain the spread of COVID-19,while Shanghai Hongqiao International Airport (SHA) saw a tremendousflight reduction.Closure of a major international airport is extremely rare and thus represents a unique opportunity to straightforwardly observe the impact of airport emissions on local air quality.In this study,a series of statistical tools were applied to analyze the variations in air pollutant levels in the vicinity of WUH and SHA.The results of bivariate polar plots show that airport SHA and WUH are a major source of nitrogen oxides.NOx,NO_(2)and NO diminished by 55.8%,44.1%,76.9%,and 40.4%,33.3% and 59.4% during the COVID-19 lockdown compared to those in the same period of 2018 and 2019,under a reduction in aircraft activities by 58.6%and61.4%.The concentration of NO_(2),SO_(2)and PM_(2.5)decreased by 77.3%,8.2%,29.5%,right after the closure of airport WUH on 23 January 2020.The average concentrations of NO,NO_(2)and NOxscatter plots at downwind of SHA after the lockdown were 78.0%,47.9%,57.4%and 62.3%,34.8%,41.8%lower than those during the same period in 2018 and 2019.However,a significant increase in O_(3)levels by 50.0% and 25.9%at WUH and SHA was observed,respectively.These results evidently show decreased nitrogen oxides concentrations in the airport vicinity due to reduced aircraft activities,while amplified O_(3)pollution due to a lower titration by NO under strong reduction in NOxemissions.展开更多
Atmospheric radiation is a major branch of atmospheric physics that encompasses the fundamental theories of atmospheric absorption,particle scattering(aerosols and clouds),and radiative transfer.Specifically,the simul...Atmospheric radiation is a major branch of atmospheric physics that encompasses the fundamental theories of atmospheric absorption,particle scattering(aerosols and clouds),and radiative transfer.Specifically,the simulations of atmospheric gaseous absorption and scattering properties of particles are the essential components of atmospheric radiative transfer models.Atmospheric radiation has important applications in weather,climate,data assimilation,remote sensing,and atmospheric detection studies.In PartⅠ,a comprehensive review of the progress in the field of gas absorption and particle scattering research over the past 30 years with a particular emphasis on the contributions from Chinese scientists is presented.The review of gas absorption includes the construction of absorption databases,the impact of different atmospheric absorption algorithms on radiative calculations,and their applications in weather and climate models and remote sensing.The review on particle scattering starts with the theoretical and computational methods and subsequently explores the optical modeling of aerosols and clouds in remote sensing and atmospheric models.Additionally,the paper discusses potential future research directions in this field.展开更多
基金supported by the Shanghai Municipal Bureau of Ecology and Environment (Environmental Research Project [2017]17 and [2018]10)the Institute of Urban Governance, Shanghai Jiao Tong University (Key Special Project of China) No. SJTU-2019UGBD-01)。
文摘Wuhan Tianhe International Airport (WUH) was suspended to contain the spread of COVID-19,while Shanghai Hongqiao International Airport (SHA) saw a tremendousflight reduction.Closure of a major international airport is extremely rare and thus represents a unique opportunity to straightforwardly observe the impact of airport emissions on local air quality.In this study,a series of statistical tools were applied to analyze the variations in air pollutant levels in the vicinity of WUH and SHA.The results of bivariate polar plots show that airport SHA and WUH are a major source of nitrogen oxides.NOx,NO_(2)and NO diminished by 55.8%,44.1%,76.9%,and 40.4%,33.3% and 59.4% during the COVID-19 lockdown compared to those in the same period of 2018 and 2019,under a reduction in aircraft activities by 58.6%and61.4%.The concentration of NO_(2),SO_(2)and PM_(2.5)decreased by 77.3%,8.2%,29.5%,right after the closure of airport WUH on 23 January 2020.The average concentrations of NO,NO_(2)and NOxscatter plots at downwind of SHA after the lockdown were 78.0%,47.9%,57.4%and 62.3%,34.8%,41.8%lower than those during the same period in 2018 and 2019.However,a significant increase in O_(3)levels by 50.0% and 25.9%at WUH and SHA was observed,respectively.These results evidently show decreased nitrogen oxides concentrations in the airport vicinity due to reduced aircraft activities,while amplified O_(3)pollution due to a lower titration by NO under strong reduction in NOxemissions.
基金Supported by the National Natural Science Foundation of China(42275039 and 42022038)。
文摘Atmospheric radiation is a major branch of atmospheric physics that encompasses the fundamental theories of atmospheric absorption,particle scattering(aerosols and clouds),and radiative transfer.Specifically,the simulations of atmospheric gaseous absorption and scattering properties of particles are the essential components of atmospheric radiative transfer models.Atmospheric radiation has important applications in weather,climate,data assimilation,remote sensing,and atmospheric detection studies.In PartⅠ,a comprehensive review of the progress in the field of gas absorption and particle scattering research over the past 30 years with a particular emphasis on the contributions from Chinese scientists is presented.The review of gas absorption includes the construction of absorption databases,the impact of different atmospheric absorption algorithms on radiative calculations,and their applications in weather and climate models and remote sensing.The review on particle scattering starts with the theoretical and computational methods and subsequently explores the optical modeling of aerosols and clouds in remote sensing and atmospheric models.Additionally,the paper discusses potential future research directions in this field.