Mole fractions of atmospheric CO2(XCO2)have been continuously measured from October 2014 to March 2016 at the Guangzhou Panyu Atmospheric Composition Site(23.00°N,113.21°E;140 m MSL)in the Pearl River Delta(...Mole fractions of atmospheric CO2(XCO2)have been continuously measured from October 2014 to March 2016 at the Guangzhou Panyu Atmospheric Composition Site(23.00°N,113.21°E;140 m MSL)in the Pearl River Delta(PRD)region using a cavity ring-down spectrometer.Approximately 66.63%,19.28%,and 14.09%of the observed values were filtered as background,pollutant source,and sink due to biospheric uptake,respectively,by applying a robust local regression procedure.Their corresponding mean values were 424.12±10.12 ppm(×10-6 mol mol-1),447.83±13.63 ppm,and 408.83±7.75 ppm.The background XCO2 levels were highest in spring and winter,moderate in autumn,and lowest in summer.The diurnal XCO2 was at a minimum from 1400-1600 LST(Local Standard Time)and a maximum at 0500 LST the next day.The increase of XCO2 in spring and summer was mainly associated with polluted air masses from south coastal Vietnam,the South China Sea,and the southeast Pearl River Estuary.With the exception of summer,airflow primarily from marine regions southeast of Taiwan that passed over the Pearl River Estuary had a greater impact on XCO2,suggesting an important potential source region.展开更多
Aerosol optical properties and direct radiative effects on surface irradiance were examined using seven years (2006-2012) of Cimel sunphotometer data collected at Panyu--the main atmospheric composition monitoring s...Aerosol optical properties and direct radiative effects on surface irradiance were examined using seven years (2006-2012) of Cimel sunphotometer data collected at Panyu--the main atmospheric composition monitoring station in the Pearl River Delta (PRD) region of China. During the dry season (October to February), mean values of the aerosol optical depth (AOD) at 550 nm, the Angstrom exponent, and the single scattering albedo at 440 nm (SSA) were 0.54, 1.33 and 0.87, respectively. About 90% of aerosols were dominated by fine-mode strongly absorbing particles. The size distribution was bimodal, with fine-mode particles dominating. The fine mode showed a peak at a radius of 0.12 μm in February and October (- 0.10 μm3 μm-2). The mean diurnal shortwave direct radiative forcing at the surface, inside the atmosphere (FATM), and at the top of the atmosphere, was -33.4± 7.0, 26.1 ± 5.6 and -7.3 ±2.7 W m-2, respectively. The corresponding mean values of aerosol direct shortwave radiative forcing per AOD were -60.0 ±7.8, 47.3 ± 8.3 and -12.8 ±3.1 W m-2, respectively. Moreover, during the study period, FATM showed a significant decreasing trend (p 〈 0.01) and SSA increased from 0.87 in 2006 to 0.91 in 2012, suggesting a decreasing trend of absorbing particles being released into the atmosphere. Optical properties and radiative impacts of the absorbing particles can be used to improve the accuracy of inversion algorithms for satellite-based aerosol retrievals in the PRD region and to better constrain the climate effect of aerosols in climate models.展开更多
基金funded by the National Key R&D Program of China(Grant No.2018YFC0213902,2019YFC0214605,2016YFC0202000)the open project of the Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration,Nanjing University of Information Science and Technology(KDW 1803)+1 种基金the Scientific and Technological Innovation Team Project of Guangzhou Joint Research Center of Atmospheric Sciences,China Meteorological Administration(Grant No.201704)the Science and Technology Research Project of Guangdong Meteorological Bureau(Grant No.GRMC2018M01)。
文摘Mole fractions of atmospheric CO2(XCO2)have been continuously measured from October 2014 to March 2016 at the Guangzhou Panyu Atmospheric Composition Site(23.00°N,113.21°E;140 m MSL)in the Pearl River Delta(PRD)region using a cavity ring-down spectrometer.Approximately 66.63%,19.28%,and 14.09%of the observed values were filtered as background,pollutant source,and sink due to biospheric uptake,respectively,by applying a robust local regression procedure.Their corresponding mean values were 424.12±10.12 ppm(×10-6 mol mol-1),447.83±13.63 ppm,and 408.83±7.75 ppm.The background XCO2 levels were highest in spring and winter,moderate in autumn,and lowest in summer.The diurnal XCO2 was at a minimum from 1400-1600 LST(Local Standard Time)and a maximum at 0500 LST the next day.The increase of XCO2 in spring and summer was mainly associated with polluted air masses from south coastal Vietnam,the South China Sea,and the southeast Pearl River Estuary.With the exception of summer,airflow primarily from marine regions southeast of Taiwan that passed over the Pearl River Estuary had a greater impact on XCO2,suggesting an important potential source region.
基金funded by the National Natural Science Foundation of China (Grant Nos. 41475105, 41475138,41405133 and 41605105)the National Key Project of MOST (Grant No. 2016YFC0202003, 2016YFC0203305, 2016YFC0201901)+2 种基金the Guangdong Province Science and Technology Plan (Grant No. 2015A020215020)the Science and Technology Innovative Research Team Plan of Guangdong Meteorological Bureau (Grant No. 201506)the Science and Technology Research Project of Guangdong Meteorological Bureau (Grant No. 2015B06)
文摘Aerosol optical properties and direct radiative effects on surface irradiance were examined using seven years (2006-2012) of Cimel sunphotometer data collected at Panyu--the main atmospheric composition monitoring station in the Pearl River Delta (PRD) region of China. During the dry season (October to February), mean values of the aerosol optical depth (AOD) at 550 nm, the Angstrom exponent, and the single scattering albedo at 440 nm (SSA) were 0.54, 1.33 and 0.87, respectively. About 90% of aerosols were dominated by fine-mode strongly absorbing particles. The size distribution was bimodal, with fine-mode particles dominating. The fine mode showed a peak at a radius of 0.12 μm in February and October (- 0.10 μm3 μm-2). The mean diurnal shortwave direct radiative forcing at the surface, inside the atmosphere (FATM), and at the top of the atmosphere, was -33.4± 7.0, 26.1 ± 5.6 and -7.3 ±2.7 W m-2, respectively. The corresponding mean values of aerosol direct shortwave radiative forcing per AOD were -60.0 ±7.8, 47.3 ± 8.3 and -12.8 ±3.1 W m-2, respectively. Moreover, during the study period, FATM showed a significant decreasing trend (p 〈 0.01) and SSA increased from 0.87 in 2006 to 0.91 in 2012, suggesting a decreasing trend of absorbing particles being released into the atmosphere. Optical properties and radiative impacts of the absorbing particles can be used to improve the accuracy of inversion algorithms for satellite-based aerosol retrievals in the PRD region and to better constrain the climate effect of aerosols in climate models.