| Carbon dioxide(CO2)and methane(CH4)are important greenhouse gases,and their monitoring and control has become a hot issue all over the world.In order to effectively control greenhouse gas emissions,it is necessary to understand its source and distribution,and to monitor emissions from various sources.Optical spectroscopy technology which has the characteristics of multi-component detection and continuous real-time detection,has become the technical mainstream of atmospheric composition monitoring.Passive differential optical absorption spectroscopy(DOAS),which use solar scattered light as a light source,has been successfully applied to measure the vertical column and spatial distribution of trace gases in the atmosphere.The weight function modified DOAS(WFM-DOAS)technology is an extended application based on passive DOAS.After correcting the problem of cross-section sensitivity to temperature and pressure in the short-wave infrared band,it is applied to the measurement of greenhouse gases.In this thesis,the research on greenhouse gas retrieval algorithm,remote sensing system,point source and regional distribution emission based on WFM-DOAS technology is carried out,which provides a new idea for greenhouse gas remote sensing technology.1.The accuracy and sensitivity of greenhouse gas retrieval based on atmospheric radiation transmission model was carried out.We establish the target gas weight function curve(WFC)in a specific scene based on the characteristics of chinese atmosphere and topography for the first time.And the effects of atmospheric temperature and pressure changes on gas absorption at different altitudes are studied by Sciatran.Through optimizing input parameters which are necessary to simulations,the accuracy of the WFC is improved.After that,the retrieval uncertainty of the target gas under the airborne and ground fixed-point remote sensing scenarios is studied.the retrieval uncertainty of parameters,which include different albedo,different geometry parameters and different solar azimuth,is obtained.The total uncertainty of CO2 column under the airplane is 1.26%,and the total uncertainty of CO2 column at fixed point is 0.30%.The results show that the parameter settings of model can meet the accuracy requirements of data retrieval.2.In order to meet the demand of distribution monitoring of greenhouse gases in large areas,an integrated airborne infrared remote sensing system is developed by the Anhui Institute of Optics and Fine Mechanics(AIOFM-CAS).The system is designed with the reflection optical introduction telescope,and includes a high-performance infrared spectrometer.Based on WFM-DOAS algorithm,the CO2 distribution in the North China Plain was carried out by using the airborne short-wave infrared remote sensing system.The CO2 distribution characteristics of Shijiazhuang,Baoding,Xingtai and Hengshui were obtained.The CO2 columns in Baoding City was the highest,which is consistent to characteristics of industrial cities with large industrial density.The system can measure spectral range of 900-1700nm with a spectral resolution of 0.4nm,and the relative retrieval error is less than 1.5%.3.In order to meet the demand of emission sources monitoring,a ground-based infrared remote sensing system is designed and integrated based on the experience of airborne remote sensing system.The greenhouse gas emission and diffusion characteristics of point sources and the distribution characteristics of water vapor were carried out.The characteristics of greenhouse gas emissions from point sources were analyzed.The experimental results show that the system is suitable for the monitoring of anthropogenic sources,such as coal-fired power plants,unorganized CO2 emissions,biological sources,geological emissions,etc.It provides a new and fast way to accurate observation of greenhouse gas distribution and emissions.And it is a new monitoring technology for atmospheric greenhouse gas detection in China. |
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