Research Of Atmospheric Greenhouse Gas Detection System And Network Monitoring Platform For Navigation Monitoring

CO2 and CH4 are the main greenhouse gases in the atmosphere,and their radiative power of greenhouse effect is about 66%and 16%respectively.Under the background of "carbon peaking" and "carbon neutralization",as the main anthropogenic carbon emission factor of the city,the demand for establishing a comprehensive and complete carbon monitoring system is increasingly strong.The main sources of urban CH4 and CO2 include industrial production emissions,human life emissions,landfill emissions,motor vehicle emissions,etc.Therefore,monitoring is faced with difficulties such as complex point source in diffusion environment,large fluctuation in measurement range,and large difference in concentration distribution in different periods.The mobile greenhouse gas monitoring system has the advantages of higher space-time resolution,lower operating cost and more flexible measurement strategy than satellite observation and ground observation in urban greenhouse gas monitoring.The paper focuses on the research of mobile urban greenhouse gas detection system and the establishment of network monitoring platform.The main work and innovation are as follows:1.A set of CO2 and CH4 analyzers with high sensitivity and large dynamic range is established by using tunable diode laser and off-axis integrating cavity,which solves the application bottleneck of narrow measuring range of off-axis integrating cavity spectrum analyzer and realizes high sensitivity and large dynamic range measurement:(1)the transmitted light intensity is proportional to the gas concentration at low concentration;(2)When the laser frequency deviates from the absorption peak at high concentration,the transmitted light intensity still has a strong nonlinear dependence on the gas concentration.Using the above two points,the CH4 and CO2 detection spectrometer ga1301 independently developed by the laboratory based on the off-axis integration cavity was re calibrated to meet the application needs of urban greenhouse gas mobile monitoring.2.Using a multi-purpose SUV(Harvard H2)as a mobile platform,equipped with GA1301,high-precision vehicle mounted base station differential GPS(fv-111)and three-dimensional ultrasonic anemometer YOUNG81000,a set of mobile greenhouse gas monitoring hardware system-navigation vehicle is established;For the selfdeveloped GA1301,a supporting user terminal is developed based on the open source Python language,replacing the Lab VIEW client.A mobile greenhouse gas monitoring terminal based on.Net platform is developed for the navigation vehicle.It can display the measured data in real time through the map and conduct visual analysis in combination with the wind speed,so as to improve the efficiency of CH4 traceability and cause analysis in the monitoring process.The urban greenhouse gas monitoring platform based on B/S mode is designed and developed.Based on the 3D map API of Gaode,the urban road monitoring data analysis and 3D display are combined with the quartile method and the background removal method.For the abnormal diffusion point source that conforms to the Gaussian model scenario,the point source emission rate is inversed by using the Gaussian diffusion model using the fixed-point measurement mode of the navigation vehicle.3.The monitoring of atmospheric CH4 and CO2 on urban roads in Hefei by time,the capture of CH4 hot spots in the city,and the monitoring of CH4 emission concentration of garbage landfills around Hefei show that the concentration distribution of CO2 and CH4 on the roads of the first ring road is generally higher than that of the second ring road.During the slow driving of natural gas vehicles,the tail gas emitted contains high CO2 and CH4,resulting in the concentration distribution of CO2 and CH4 in Hefei City in the late peak period showing a certain business circle;Based on the"fingerprint" analysis of CO2 and CH4 in hot spots in cities,the point sources are mainly divided into fixed point sources:natural gas stations,iron and steel plants,and chemical production ponds,and mobile point sources:natural gas vehicles;Based on the observation of four landfills,it is found that there are two high concentration CH4 emissions in Longquan Mountain domestic waste landfill due to the reconstruction construction;There is a high concentration of CH4 fugitive emission during the rush hour of work in Feixi municipal solid waste landfill,and the emission rate is 109788 mg/s higher than that during the working hours.