A global two-dimensional zonally averaged chemistry model is developed to study the chemi-cal composition of atmosphere. The region of the model is from 90°S to 90°N and from the ground to the altitude of 20...A global two-dimensional zonally averaged chemistry model is developed to study the chemi-cal composition of atmosphere. The region of the model is from 90°S to 90°N and from the ground to the altitude of 20 km with a resolution of 5° x 1 km. The wind field is residual circulation calcu-lated from diabatic rate. 34 species and 104 chemical and photochemical reactions are considered in the model. The sources of CH4, CO and NOx, which are divided into seasonal sources and non-seasonal sources, are parameterized as a function of latitude and time. The chemical composi-tion of atmosphere was simulated with emission level of CH4, CO and NOx in 1990. The results are compared with observations and other model results, showing that the model is successful to simu-late the atmospheric chemical composition and distribution of CH4. Key words Global two-dimensional chemistry model - Atmospheric composition - Emission This work was supported by the State Key Program for basic research “ Climate Dynamics and Cli-mate Prediction Theory” (Pandeng-yu-21).The authors would like to express their thanks to the National Oceanic and Atmospheric Administration (NOAA), Climate Monitoring and Diagnostics Laboratory (CMDL), Carbon Cycle Group for providing the observational data of CO and CH4.展开更多
Samples of fog water collected in the area of Guangzhou during February, March and April of 2005 are used in this work to study the chemical composition of fog water in polluting fog there. Three typical episodes of p...Samples of fog water collected in the area of Guangzhou during February, March and April of 2005 are used in this work to study the chemical composition of fog water in polluting fog there. Three typical episodes of polluting fog are analyzed in terms of ionic concentration and their possible sources. It is found that the concentration of various ions in fog water is much higher than those in rainwater. Fog not only blocks visual range but contains liquid particles that result in high degree of pollution and are very harmful to human health. SO4= is the anion with the highest concentration in fog water, followed by NO3-. For the cation, Ca++ and NH4+ are the highest in concentration. It is then known that rainwater is more acidic than fog water, indicating that ionic concentration of fog water is much higher than that of rainwater, but there are much more buffering materials in fog water, like NH4+ and Ca++. There is significant enrichment of Ca++, SO4=, and Mg++ in fog water. In the Guangzhou area, fog water from polluting fog is mainly influenced continental environment and human activity. The episodes of serious fog pollution during the time have immediate relationships with the presence of abundant water vapor and large amount of polluting aerosol particles.展开更多
Atmospheric water vapor is a critical component of the Earth's water cycle and has significant impacts on weather,climate,and atmospheric chemistry.However,deficiencies remain in the coverage and accuracy of water...Atmospheric water vapor is a critical component of the Earth's water cycle and has significant impacts on weather,climate,and atmospheric chemistry.However,deficiencies remain in the coverage and accuracy of water vapor monitoring.In this study,we first retrieved the total column water vapor(TCWV)in the visible blue spectral band from two Chinese satellite UV-Vis spectrometers,the Environmental Trace Gases Monitoring Instruments(EMIs),which are onboard the Chinese GaoFen-5(GF-5,since May 2018)and GaoFen-5B(GF-5B,since September 2021)satellites.Nevertheless,limited by factors such as the relatively lower spectral signal-to-noise ratio and weak absorption of water vapor,the accurate retrieval of TCWV from the EMI spectrum is rather challenging.Therefore,we improved the baseline TCWV retrieval based on the differential optical absorption technique,including the re-calibration of the on-orbit spectra,optimization of the spectral fitting,and bias correction in the fitted result.Sensitivity tests show that the mean retrieval TCWV error of the EMI decreased by 1.47 kg m-2compared to that using uncalibrated spectra.The improved spectral fitting significantly reduced the relative uncertainty of the water vapor slant column densities(SCD)by 13.42%,and increased the number of successful fits by 11.64%.The improved EMI TCWV retrieval results from both the GF-5 and GF-5B satellites show a trend consistent with the TROPOspheric Monitoring Instrument(TROPOMI)satellite observations,with a correlation coefficient(R)of 0.98 and a mean bias of 1.04 kg m-2(6.88%).Ground-based validations showed that the correlation between the EMI TCWV retrievals from the GF-5B satellite(R=0.91)and sun photometer measurements was significantly higher than that from the GF-5 satellite(R=0.87),which may have been due to the improved performance of the EMI instrument on the GF-5B satellite.Finally,we showed that an intense atmospheric river event could be successfully captured by EMI TCWV measurements,which could support the monitoring and forecasting of global weather and climate.Our results demonstrate the feasibility of the proposed TCWV retrieval algorithm for EMI instruments and their followon satellite sensors and contribute to the generation of a globally stable and consistent TCWV dataset with morning and afternoon overpass measurements from the blue band spectra.展开更多
By using Constellation Observing System for Meteorology, Ionosphere, and Climate satellite observa- tions, and Global Ionosphere and Thermosphere Model simulations, the altitudinal dependences of the longitudinal diff...By using Constellation Observing System for Meteorology, Ionosphere, and Climate satellite observa- tions, and Global Ionosphere and Thermosphere Model simulations, the altitudinal dependences of the longitudinal differences in electron densities Ne were studied at mid- latitudes for the first time. Distinct altitudinal dependences were revealed： （1） In the northern （southern） hemisphere, there were wave-1 variations mainly in the daytime in the altitudes below 180 km, but wave-2 （wave-l） variations over a whole day above 220 km; （2） a transition （or sep- aration） layer occurred mainly in the daytime within 180 and 220 km, showing reversed longitudinal variation from that at lower altitudes. Solar illumination was one of the plausible mechanisms for the zonal difference of Ne at lower altitudes. At higher altitudes, both neutral winds and solar illumination played important roles. The neutral winds effects accounted for the longitudinal differences in Ne in the European-Asian sector. Neutral composition changes and neutral wind effects both contributed to the formation of the transition layer.展开更多
This review analyzes the state and recent progress in the field of information support for pollen allergy sufferers.For decades,information available for the patients and allergologists consisted of pollen counts,whic...This review analyzes the state and recent progress in the field of information support for pollen allergy sufferers.For decades,information available for the patients and allergologists consisted of pollen counts,which are vital but insufficient.New technology paves the way to substantial increase in amount and diversity of the data.This paper reviews old and newly suggested methods to predict pollen and air pollutant concentrations in the air and proposes an allergy risk concept,which combines the pollen and pollution information and transforms it into a qualitative risk index.This new index is available in an app(Mobile Airways Sentinel NetworK-air)that was developed in the frame of the European Union grant Impact of Air POLLution on sleep,Asthma and Rhinitis(a project of European Institute of Innovation and Technology-Health).On-going transformation of the pollen allergy information support is based on new technological solutions for pollen and air quality monitoring and predictions.The new information-technology and artificial-intelligence-based solutions help to convert this information into easy-to-use services for both medical practitioners and allergy sufferers.展开更多
Land plants evolved from aquatic green algal ancestors to dominate terrestrial ecosystems approximately 480 million years ago during the Ordovician period(Hammarlund et al.,2020).This major event in Earth's life h...Land plants evolved from aquatic green algal ancestors to dominate terrestrial ecosystems approximately 480 million years ago during the Ordovician period(Hammarlund et al.,2020).This major event in Earth's life history triggered broad and lasting changes in the composition of the atmosphere,including a decline in carbon dioxide(CO_(2))due to photosynthesis-driven carbon sequestration and increases in molecular oxygen(O_(2))concentrations(Holdsworth and Gibbs,2020).展开更多
文摘A global two-dimensional zonally averaged chemistry model is developed to study the chemi-cal composition of atmosphere. The region of the model is from 90°S to 90°N and from the ground to the altitude of 20 km with a resolution of 5° x 1 km. The wind field is residual circulation calcu-lated from diabatic rate. 34 species and 104 chemical and photochemical reactions are considered in the model. The sources of CH4, CO and NOx, which are divided into seasonal sources and non-seasonal sources, are parameterized as a function of latitude and time. The chemical composi-tion of atmosphere was simulated with emission level of CH4, CO and NOx in 1990. The results are compared with observations and other model results, showing that the model is successful to simu-late the atmospheric chemical composition and distribution of CH4. Key words Global two-dimensional chemistry model - Atmospheric composition - Emission This work was supported by the State Key Program for basic research “ Climate Dynamics and Cli-mate Prediction Theory” (Pandeng-yu-21).The authors would like to express their thanks to the National Oceanic and Atmospheric Administration (NOAA), Climate Monitoring and Diagnostics Laboratory (CMDL), Carbon Cycle Group for providing the observational data of CO and CH4.
基金Natural Science Foundation of China (40375002, 40418008, 40775011, U0733004)Project 863 (2006AA06A306, 2006AA06A308)+3 种基金National Basic Research Program of China (973 Program):2005CB422207Natural Science Foundation of Guangdong Province (033029)Project of Key Scientific Research of Guangdong Province (2004A30401002, 2005B32601011)Project of Applied Fundamental Research of Guangzhou (2004J1-0021)
文摘Samples of fog water collected in the area of Guangzhou during February, March and April of 2005 are used in this work to study the chemical composition of fog water in polluting fog there. Three typical episodes of polluting fog are analyzed in terms of ionic concentration and their possible sources. It is found that the concentration of various ions in fog water is much higher than those in rainwater. Fog not only blocks visual range but contains liquid particles that result in high degree of pollution and are very harmful to human health. SO4= is the anion with the highest concentration in fog water, followed by NO3-. For the cation, Ca++ and NH4+ are the highest in concentration. It is then known that rainwater is more acidic than fog water, indicating that ionic concentration of fog water is much higher than that of rainwater, but there are much more buffering materials in fog water, like NH4+ and Ca++. There is significant enrichment of Ca++, SO4=, and Mg++ in fog water. In the Guangzhou area, fog water from polluting fog is mainly influenced continental environment and human activity. The episodes of serious fog pollution during the time have immediate relationships with the presence of abundant water vapor and large amount of polluting aerosol particles.
基金supported by the National Natural Science Foundation of China(Grant Nos.42225504,42375120&62305322)the National Key Research and Development Program of China(Grant No.2022YFC3700100)+1 种基金the Major Project of High Resolution Earth Observation System(Grant No.30-Y60B01-9003-22/23)the Fundamental Research Funds for the Central Universities(Grant Nos.YD2090002021&WK2090000038)。
文摘Atmospheric water vapor is a critical component of the Earth's water cycle and has significant impacts on weather,climate,and atmospheric chemistry.However,deficiencies remain in the coverage and accuracy of water vapor monitoring.In this study,we first retrieved the total column water vapor(TCWV)in the visible blue spectral band from two Chinese satellite UV-Vis spectrometers,the Environmental Trace Gases Monitoring Instruments(EMIs),which are onboard the Chinese GaoFen-5(GF-5,since May 2018)and GaoFen-5B(GF-5B,since September 2021)satellites.Nevertheless,limited by factors such as the relatively lower spectral signal-to-noise ratio and weak absorption of water vapor,the accurate retrieval of TCWV from the EMI spectrum is rather challenging.Therefore,we improved the baseline TCWV retrieval based on the differential optical absorption technique,including the re-calibration of the on-orbit spectra,optimization of the spectral fitting,and bias correction in the fitted result.Sensitivity tests show that the mean retrieval TCWV error of the EMI decreased by 1.47 kg m-2compared to that using uncalibrated spectra.The improved spectral fitting significantly reduced the relative uncertainty of the water vapor slant column densities(SCD)by 13.42%,and increased the number of successful fits by 11.64%.The improved EMI TCWV retrieval results from both the GF-5 and GF-5B satellites show a trend consistent with the TROPOspheric Monitoring Instrument(TROPOMI)satellite observations,with a correlation coefficient(R)of 0.98 and a mean bias of 1.04 kg m-2(6.88%).Ground-based validations showed that the correlation between the EMI TCWV retrievals from the GF-5B satellite(R=0.91)and sun photometer measurements was significantly higher than that from the GF-5 satellite(R=0.87),which may have been due to the improved performance of the EMI instrument on the GF-5B satellite.Finally,we showed that an intense atmospheric river event could be successfully captured by EMI TCWV measurements,which could support the monitoring and forecasting of global weather and climate.Our results demonstrate the feasibility of the proposed TCWV retrieval algorithm for EMI instruments and their followon satellite sensors and contribute to the generation of a globally stable and consistent TCWV dataset with morning and afternoon overpass measurements from the blue band spectra.
文摘By using Constellation Observing System for Meteorology, Ionosphere, and Climate satellite observa- tions, and Global Ionosphere and Thermosphere Model simulations, the altitudinal dependences of the longitudinal differences in electron densities Ne were studied at mid- latitudes for the first time. Distinct altitudinal dependences were revealed： （1） In the northern （southern） hemisphere, there were wave-1 variations mainly in the daytime in the altitudes below 180 km, but wave-2 （wave-l） variations over a whole day above 220 km; （2） a transition （or sep- aration） layer occurred mainly in the daytime within 180 and 220 km, showing reversed longitudinal variation from that at lower altitudes. Solar illumination was one of the plausible mechanisms for the zonal difference of Ne at lower altitudes. At higher altitudes, both neutral winds and solar illumination played important roles. The neutral winds effects accounted for the longitudinal differences in Ne in the European-Asian sector. Neutral composition changes and neutral wind effects both contributed to the formation of the transition layer.
文摘This review analyzes the state and recent progress in the field of information support for pollen allergy sufferers.For decades,information available for the patients and allergologists consisted of pollen counts,which are vital but insufficient.New technology paves the way to substantial increase in amount and diversity of the data.This paper reviews old and newly suggested methods to predict pollen and air pollutant concentrations in the air and proposes an allergy risk concept,which combines the pollen and pollution information and transforms it into a qualitative risk index.This new index is available in an app(Mobile Airways Sentinel NetworK-air)that was developed in the frame of the European Union grant Impact of Air POLLution on sleep,Asthma and Rhinitis(a project of European Institute of Innovation and Technology-Health).On-going transformation of the pollen allergy information support is based on new technological solutions for pollen and air quality monitoring and predictions.The new information-technology and artificial-intelligence-based solutions help to convert this information into easy-to-use services for both medical practitioners and allergy sufferers.
基金FUNDING D.J.G.and L.Z were supported by Biotechnology and Biological Sciences Research Council grants BB/Y006062/1 and BB/Y002512/1.
文摘Land plants evolved from aquatic green algal ancestors to dominate terrestrial ecosystems approximately 480 million years ago during the Ordovician period(Hammarlund et al.,2020).This major event in Earth's life history triggered broad and lasting changes in the composition of the atmosphere,including a decline in carbon dioxide(CO_(2))due to photosynthesis-driven carbon sequestration and increases in molecular oxygen(O_(2))concentrations(Holdsworth and Gibbs,2020).
