Research Of Atmospheric Aerosol Types Identification And Radiation Characteristic Based On MODIS Satellite

The efficient utilization of solar energy can effectively alleviate the contradiction between supply and demand of energy in China.With the aggravation of air pollution,however,atmospheric aerosols seriously affect the efficient utilization of solar energy and the efficiency of light heat conversion.Atmospheric aerosol usually refers to solid or liquid particulate matter with an aerodynamic diameter in the range of 0.001 to 100 ?m suspended in the atmospheric environment.As one of the largest uncertainties in present climate research,aerosol can indirectly and directly alter the Earth radiation budget and global or regional climate,and the scale of influence is dominated by their type.Distinguishing aerosol types in the atmosphere,combined with studies on the climatic effects of a type of aerosol,can effectively determine the impacts of aerosols on the earth-atmosphere system.Classifying aerosol types,however,is challenging because of the large spatiotemporal heterogeneity of aerosol properties that originates from the geographically diverse sources and short lifetime.Therefore,establishing an accurate and effective aerosol type recognition model,and carrying out spatially continuous regional aerosol type recognition research on this basis has important theoretical significance and application value,which can effectively promote the understanding of aerosol radiation characteristics and climate effects.In this paper,atmospheric pollution conditions are introduced into the performance evaluation system of satellite remote sensing aerosol data.Combined with the concept of aerosol relative optical thickness,a 2D-space aerosol classification model was established,which provided a basis for regional aerosol type recognition using satellite data.Finally,the model identification results are used to establish the look-up table of aerosol optical properties in Taipei,and the SBDART model is used to numerically characterize the aerosol radiation properties in the area.The main research content includes three aspects below:(1)All MODIS aerosol samples were divided by using a spatial resolution of 0.1°×0.1°,the MODIS-AOD spatiotemporal distribution and accuracy validation on an annual basis were analyzed under annual and seasonal scales.Air conditions were divided into four regimes according to the Surface PM2.5 monitoring data.The MODIS-AOD performances are validated by using AERONET AOD data for various pollution situations and aerosol types.The results show that the DT algorithm was found to provide more accurate data in autumn and winter,but often fails to obtain valid data in winter.In contrast,the DB algorithm can provide nationwide AOD data in all seasons.Under comparable pollution conditions,the DT AOD data display strong anti-interference and high accuracy qualities,whereas the DB algorithm can yield a larger amount of valid AOD.(2)Established a 2D-space aerosol classification model that is suitable for MODIS AOD bands,and assessed the feasibility of the model to classify aerosols over eight typical regions in the world.The accuracy verification of model includes:verification based on ground-based data,verification based on satellite data,daily contrast of aerosol classification results between ground-based and satellite-based,individual case verification,and regional identification verification.The results show that the model established in this paper has the ability to identify different types of aerosols and can support spatially continuous aerosol recognition research.(3)The aerosol radiative forcing characteristics under different atmospheric background conditions in Taipei,China were numerically characterized using the 2D-space aerosol classification model,MODIS aerosol product,the ground-based remote sensing platform and the SBDART model.The results show that the DARF presents a seasonal pattern of high summer and low winter in the study period.The DARF value is closely related to the type of aerosol particles,and the corresponding DARF of different types of aerosol particles is obviously different.Urban-industry aerosols were the main contributor of high DARF.