Understanding the vertical distribution of ozone is crucial when assessing both its horizontal and vertical transport,as well as when analyzing the physical and chemical properties of the atmosphere.One of the most ef...Understanding the vertical distribution of ozone is crucial when assessing both its horizontal and vertical transport,as well as when analyzing the physical and chemical properties of the atmosphere.One of the most effective ways to obtain high spatial resolution ozone profiles is through satellite observations.The Environmental Trace Gases Monitoring Instrument(EMI)deployed on the Gaofen-5 satellite is the first Chinese ultraviolet-visible hyperspectral spectrometer.However,retrieving ozone profiles using backscattered radiance values measured by the EMI is challenging due to unavailable measurement errors and a low signal-to-noise ratio.The algorithm developed for the Tropospheric Monitoring Instrument did not allow us to retrieve 87%of the EMI pixels.Therefore,we developed an algorithm specific to the characteristics of the EMI.The fitting residuals are smaller than 0.3%in most regions.The retrieved ozone profiles were in good agreement with ozonesonde data,with maximum mean biases of 20%at five latitude bands.By applying EMI averaging kernels to the ozonesonde profiles,the integrated stratospheric column ozone and tropospheric column ozone also showed excellent agreement with ozonesonde data,The lower layers(0-7.5 km)of the EMI ozone profiles reflected the seasonal variation in surface ozone derived from the China National Environmental Monitoring Center(CNEMC).However,the upper layers(9.7-16.7 km)of the ozone profiles show different trends,with the ozone peak occurring at an altitude of 9.7-16.7 km in March,2019.A stratospheric intrusion event in central China from August 11 to 15,2019,is captured using the EMI ozone profiles,potential vorticity data,and relative humidity data.The increase in the CNEMC ozone co ncentration showed that downward transport enhanced surface ozone pollution.展开更多
Abundances of a range of air pollutants can be inferred from satellite UV-Vis spectroscopy measurements by using the unique absorption signatures of gas species.Here,we implemented several spectral fitting methods to ...Abundances of a range of air pollutants can be inferred from satellite UV-Vis spectroscopy measurements by using the unique absorption signatures of gas species.Here,we implemented several spectral fitting methods to retrieve tropospheric NO_(2),SO_(2),and HCHO from the ozone monitoring instrument(OMI),with radiative simulations providing necessary information on the interactions of scattered solar light within the atmosphere.We analyzed the spatial distribution and temporal trends of satellite-observed air pollutants over eastern China during 2005-2017,especially in heavily polluted regions.We found significant decreasing trends in NO_(2) and SO_(2) since 2011 over most regions,despite varying temporal features and turning points.In contrast,an overall increasing trend was identified for tropospheric HCHO over these regions in recent years.Furthermore,generalized additive models were implemented to understand the driving forces of air quality trends in China and assess the effectiveness of emission controls.Our results indicated that although meteorological parameters,such as wind,water vapor,solar radiation and temperature,mainly dominated the day-to-day and seasonal fluctuations in air pollutants,anthropogenic emissions played a unique role in the long-term variation in the ambient concentrations of NO_(2),SO_(2),and HCHO in the past 13 years.Generally,recent declines in NO_(2) and SO_(2) could be attributed to emission reductions due to effective air quality policies,and the opposite trends in HCHO may urge the need to control anthropogenic volatile organic compound(VOC)emissions.展开更多
In response to the COVID-19 pandemic,governments worldwide imposed lockdown measures in early 2020,resulting in notable reductions in air pollutant emissions.The changes in air quality during the pandemic have been in...In response to the COVID-19 pandemic,governments worldwide imposed lockdown measures in early 2020,resulting in notable reductions in air pollutant emissions.The changes in air quality during the pandemic have been investigated in numerous studies via satellite observations.Nevertheless,no relevant research has been gathered using Chinese satellite instruments,because the poor spectral quality makes it extremely difficult to retrieve data from the spectra of the Environmental Trace Gases Monitoring Instrument(EMI),the first Chinese satellite-based ultraviolet–visible spectrometer monitoring air pollutants.However,through a series of remote sensing algorithm optimizations from spectral calibration to retrieval,we successfully retrieved global gaseous pollutants,such as nitrogen dioxide(NO2),sulfur dioxide(SO2),and formaldehyde(HCHO),from EMI during the pandemic.The abrupt drop in NO2 successfully captured the time for each city when effective measures were implemented to prevent the spread of the pandemic,for example,in January 2020 in Chinese cities,February in Seoul,and March in Tokyo and various cities across Europe and America.Furthermore,significant decreases in HCHO in Wuhan,Shanghai,Guangzhou,and Seoul indicated that the majority of volatile organic compounds(VOCs)emissions were anthropogenic.Contrastingly,the lack of evident reduction in Beijing and New Delhi suggested dominant natural sources of VOCs.By comparing the relative variation of NO2 to gross domestic product(GDP),we found that the COVID-19 pandemic had more influence on the secondary industry in China,while on the primary and tertiary industries in Korea and the countries across Europe and America.展开更多
基金supported by the National Natural Science Foundation of China(42225504 and 41977184)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA23020301)+3 种基金the Key Research and Development Project of Anhui Province(202104i07020002)the Major Projects of High Resolution Earth Observation Systems of National Science and Technology(05-Y30B01-9001-19/20-3)the Key Laboratory of Atmospheric Chemistry/China Meteorological Administration(LAC/CMA)(2022B06)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2021443).
文摘Understanding the vertical distribution of ozone is crucial when assessing both its horizontal and vertical transport,as well as when analyzing the physical and chemical properties of the atmosphere.One of the most effective ways to obtain high spatial resolution ozone profiles is through satellite observations.The Environmental Trace Gases Monitoring Instrument(EMI)deployed on the Gaofen-5 satellite is the first Chinese ultraviolet-visible hyperspectral spectrometer.However,retrieving ozone profiles using backscattered radiance values measured by the EMI is challenging due to unavailable measurement errors and a low signal-to-noise ratio.The algorithm developed for the Tropospheric Monitoring Instrument did not allow us to retrieve 87%of the EMI pixels.Therefore,we developed an algorithm specific to the characteristics of the EMI.The fitting residuals are smaller than 0.3%in most regions.The retrieved ozone profiles were in good agreement with ozonesonde data,with maximum mean biases of 20%at five latitude bands.By applying EMI averaging kernels to the ozonesonde profiles,the integrated stratospheric column ozone and tropospheric column ozone also showed excellent agreement with ozonesonde data,The lower layers(0-7.5 km)of the EMI ozone profiles reflected the seasonal variation in surface ozone derived from the China National Environmental Monitoring Center(CNEMC).However,the upper layers(9.7-16.7 km)of the ozone profiles show different trends,with the ozone peak occurring at an altitude of 9.7-16.7 km in March,2019.A stratospheric intrusion event in central China from August 11 to 15,2019,is captured using the EMI ozone profiles,potential vorticity data,and relative humidity data.The increase in the CNEMC ozone co ncentration showed that downward transport enhanced surface ozone pollution.
基金supported by grants from the National Natural Science Foundation of China(Nos.41722501,91544212,51778596,41575021,41875043,and 41977184)the National Key Research and Development Program of China(Nos.2018YFC0213104,2017YFC0210002,and 2016YFC0203302)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA23020301)the National Key Project for Causes and Control of Heavy Air Pollution(Nos.DQGG0102 and DQGG0205)the Major Projects of High Resolution Earth Observation Systems of National Science and Technology(05-Y30B01-9001-19/20-1).
文摘Abundances of a range of air pollutants can be inferred from satellite UV-Vis spectroscopy measurements by using the unique absorption signatures of gas species.Here,we implemented several spectral fitting methods to retrieve tropospheric NO_(2),SO_(2),and HCHO from the ozone monitoring instrument(OMI),with radiative simulations providing necessary information on the interactions of scattered solar light within the atmosphere.We analyzed the spatial distribution and temporal trends of satellite-observed air pollutants over eastern China during 2005-2017,especially in heavily polluted regions.We found significant decreasing trends in NO_(2) and SO_(2) since 2011 over most regions,despite varying temporal features and turning points.In contrast,an overall increasing trend was identified for tropospheric HCHO over these regions in recent years.Furthermore,generalized additive models were implemented to understand the driving forces of air quality trends in China and assess the effectiveness of emission controls.Our results indicated that although meteorological parameters,such as wind,water vapor,solar radiation and temperature,mainly dominated the day-to-day and seasonal fluctuations in air pollutants,anthropogenic emissions played a unique role in the long-term variation in the ambient concentrations of NO_(2),SO_(2),and HCHO in the past 13 years.Generally,recent declines in NO_(2) and SO_(2) could be attributed to emission reductions due to effective air quality policies,and the opposite trends in HCHO may urge the need to control anthropogenic volatile organic compound(VOC)emissions.
基金supported by the National Key Research and Development Program of China (2018YFC0213104, 2017YFC0210002, 2016YFC0203302 and 2017YFC0212800)the National Natural Science Foundation of China (41722501, 91544212, 51778596, 41575021, 41977184 and 41875043)+4 种基金Anhui Science and Technology Major Project (18030801111)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA23020301)the National Key Project for Causes and Control of Heavy Air Pollution (DQGG0102 and DQGG0205)the National High-Resolution Earth Observation Project of China (05-Y30B019001-19/20-3)Civil Aerospace Technology Advance Research Project (Y7K00100KJ)
基金This research was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA23020301)the National Key Research and Development Program of China(No.2018YFC0213104 and 2017YFC0210002)+4 种基金the National Natural Science Foundation of China(No.41977184,41941011,and 51778596)the Key Research and Development Project of Anhui Province(202104i07020002)the Major Projects of High Resolution Earth Observation Systems of National Science and Technology(05-Y30B01-9001-19/20-3)the Youth Innovation Promotion Association of CAS(2021443)the Young Talent Project of the Center for Excellence in Regional Atmospheric Environment,CAS(CERAE202004).
文摘In response to the COVID-19 pandemic,governments worldwide imposed lockdown measures in early 2020,resulting in notable reductions in air pollutant emissions.The changes in air quality during the pandemic have been investigated in numerous studies via satellite observations.Nevertheless,no relevant research has been gathered using Chinese satellite instruments,because the poor spectral quality makes it extremely difficult to retrieve data from the spectra of the Environmental Trace Gases Monitoring Instrument(EMI),the first Chinese satellite-based ultraviolet–visible spectrometer monitoring air pollutants.However,through a series of remote sensing algorithm optimizations from spectral calibration to retrieval,we successfully retrieved global gaseous pollutants,such as nitrogen dioxide(NO2),sulfur dioxide(SO2),and formaldehyde(HCHO),from EMI during the pandemic.The abrupt drop in NO2 successfully captured the time for each city when effective measures were implemented to prevent the spread of the pandemic,for example,in January 2020 in Chinese cities,February in Seoul,and March in Tokyo and various cities across Europe and America.Furthermore,significant decreases in HCHO in Wuhan,Shanghai,Guangzhou,and Seoul indicated that the majority of volatile organic compounds(VOCs)emissions were anthropogenic.Contrastingly,the lack of evident reduction in Beijing and New Delhi suggested dominant natural sources of VOCs.By comparing the relative variation of NO2 to gross domestic product(GDP),we found that the COVID-19 pandemic had more influence on the secondary industry in China,while on the primary and tertiary industries in Korea and the countries across Europe and America.
