The objective of this investigation was to study whether it is possible to determine the air tightness of covered slurry storage tanks using tracer gas technique by injection of sulphur hexafluoride （SF6） and measur...The objective of this investigation was to study whether it is possible to determine the air tightness of covered slurry storage tanks using tracer gas technique by injection of sulphur hexafluoride （SF6） and measurements of the decay in gas concentrations with an infrared spectrophotometer in the air space above the slurry. By measuring the decay in concentration of injected tracer gas at different occasions, the air exchange rate was determined. Three different types of coverings were studied namely; wooden roof, plastic tent and concrete roof.展开更多
Within a LIFE＋ project IPNOA （improved flux prototype for n2o emission from agriculture）, LIFE11 ENV/IT/302 is a mobile prototype was developed to evaluate at field scale N20 emissions using a fast chamber techniqu...Within a LIFE＋ project IPNOA （improved flux prototype for n2o emission from agriculture）, LIFE11 ENV/IT/302 is a mobile prototype was developed to evaluate at field scale N20 emissions using a fast chamber technique. Main challenge was to develop a mobile system capable of moving on various field surfaces, equipped with very reliable N20 gas analyser （Los Gatos Research Inc.）, electrically autonomous （with batteries） and enough robust to face up to field conditions. In this paper, we report the major features of this prototype studied during two field campaigns. The N20 flux IPNOA prototype was compared with other methodological implementations： first, during an INGOS （integrated non-CO2 greenhouse gas observing systems） campaign on a grazed grassland at Easter Bush （Scotland） by Eddy correlation method, and then after on an arable crop at Grignon （France） using automatic and manual chambers fitted with QC-TILDAS （Quantum Cascade Tunable Infrared Laser Differential Absorption Spectrometer, Aerodyne Research Inc.）, with the 46C model of thermo-instrument analyser or with a GC （gas chromatography） analysis.展开更多
We simulated geostationary satellite observations to assess the potential for high spatial-and temporal-resolution monitoring of air pollution in China with a focus on tropospheric ozone(O_3), nitrogen dioxide(NO_2), ...We simulated geostationary satellite observations to assess the potential for high spatial-and temporal-resolution monitoring of air pollution in China with a focus on tropospheric ozone(O_3), nitrogen dioxide(NO_2), sulfur dioxide(SO_2), and formaldehyde(HCHO). Based on the capabilities and parameters of the payloads onboard sun-synchronous satellites, we simulated the observed spectrum based on a radiative transfer model using a geostationary satellite model. According to optimal estimation theory, we analyzed the sensitivities and retrieval uncertainties of the main parameters of the instrument for the target trace gases. Considering the retrieval error requirements of each trace gas, we determined the major instrument parameter values(e.g., observation channel, spectral resolution, and signal-to-noise ratio). To evaluate these values, retrieval simulation was performed based on the three-dimensional distribution of the atmospheric components over China using an atmospheric chemical transportation model. As many as 90% of the experiments met the retrieval requirements for all target gases. The retrieval precision of total-column and stratospheric O_3 was 2%. In addition, effective retrieval of all trace gases could be achieved at solar zenith angles larger than 70°. Therefore, the geostationary satellite observation and instrument parameters provided herein can be used in air pollution monitoring in China. This study offers a theoretical basis and simulation tool for improving the design of instruments onboard geostationary satellites.展开更多
文摘The objective of this investigation was to study whether it is possible to determine the air tightness of covered slurry storage tanks using tracer gas technique by injection of sulphur hexafluoride （SF6） and measurements of the decay in gas concentrations with an infrared spectrophotometer in the air space above the slurry. By measuring the decay in concentration of injected tracer gas at different occasions, the air exchange rate was determined. Three different types of coverings were studied namely; wooden roof, plastic tent and concrete roof.
文摘Within a LIFE＋ project IPNOA （improved flux prototype for n2o emission from agriculture）, LIFE11 ENV/IT/302 is a mobile prototype was developed to evaluate at field scale N20 emissions using a fast chamber technique. Main challenge was to develop a mobile system capable of moving on various field surfaces, equipped with very reliable N20 gas analyser （Los Gatos Research Inc.）, electrically autonomous （with batteries） and enough robust to face up to field conditions. In this paper, we report the major features of this prototype studied during two field campaigns. The N20 flux IPNOA prototype was compared with other methodological implementations： first, during an INGOS （integrated non-CO2 greenhouse gas observing systems） campaign on a grazed grassland at Easter Bush （Scotland） by Eddy correlation method, and then after on an arable crop at Grignon （France） using automatic and manual chambers fitted with QC-TILDAS （Quantum Cascade Tunable Infrared Laser Differential Absorption Spectrometer, Aerodyne Research Inc.）, with the 46C model of thermo-instrument analyser or with a GC （gas chromatography） analysis.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41375035, 41205018)
文摘We simulated geostationary satellite observations to assess the potential for high spatial-and temporal-resolution monitoring of air pollution in China with a focus on tropospheric ozone(O_3), nitrogen dioxide(NO_2), sulfur dioxide(SO_2), and formaldehyde(HCHO). Based on the capabilities and parameters of the payloads onboard sun-synchronous satellites, we simulated the observed spectrum based on a radiative transfer model using a geostationary satellite model. According to optimal estimation theory, we analyzed the sensitivities and retrieval uncertainties of the main parameters of the instrument for the target trace gases. Considering the retrieval error requirements of each trace gas, we determined the major instrument parameter values(e.g., observation channel, spectral resolution, and signal-to-noise ratio). To evaluate these values, retrieval simulation was performed based on the three-dimensional distribution of the atmospheric components over China using an atmospheric chemical transportation model. As many as 90% of the experiments met the retrieval requirements for all target gases. The retrieval precision of total-column and stratospheric O_3 was 2%. In addition, effective retrieval of all trace gases could be achieved at solar zenith angles larger than 70°. Therefore, the geostationary satellite observation and instrument parameters provided herein can be used in air pollution monitoring in China. This study offers a theoretical basis and simulation tool for improving the design of instruments onboard geostationary satellites.
