Research Review of Remote Sensing for Atmospheric Aerosol Retrieval

Air aerosol pollution has become increasingly serious and become the focus of atmospheric research with the development of urban industrialization.Remote sensing technology is widely used in atmospheric research as a means of scientific,rapid and large-scale monitoring.The main content of remote sensing for atmospheric aerosol retrieval including Aerosol Optical Depth (AOD) of aerosol,aerosol concentration aerosol particle size distribution and air pollution are analyzed based on the atmospheric radiation transmission theory.Main progress around of the world in areas of atmospheric aerosol research by remote sensing techniques are introduced,especially the advantages and disadvantages of the different aerosol retrieval algorithms.At last,some existing problems and the trend of remote sensing for atmospheric aerosol retrieval are discussed.     

基于Himawari-8的气溶胶反演研究

为获取中国区域高时空分辨率、高精度的气溶胶光学厚度（AOD）产品。基于Himawari-8卫星数据和MODIS地表反射率产品,反演了中国区域2018年4月~2019年4月逐10分钟的AOD,该方法可同时对暗像元、亮像元区域进行反演。依托全球气溶胶观测网（AERONET）中国境内的6个观测站数据,对反演结果进行一致性检验,同时将AOD反演结果与Himawari-8官方最新发布的AOD产品（020版）进行对比。结果表明：①红蓝比值法AOD反演结果与AERONET AOD之间相关性很高,除包头站外,其余5个站点的相关系数R在0.728~0.863之间,EE（误差期望）范围内样本点百分比在47.7%~68.6%之间,与Himawari-8 AOD产品相比有很大优势;②红蓝比值法AOD反演结果与AERONET AOD在时间序列走势上基本一致,但在AOD >1时,反演结果较AERONET AOD偏高。Himawari-8 AOD春夏季走势相对于AERONET AOD较为一致,但由于秋冬季Himawari-8 AOD有明显的日变化,且日变化较大,其走势与AERONET AOD偏离较大;③红蓝比值法AOD反演结果与MODIS AOD产品空间分布基本一致,AOD反演结果总体较MODIS AOD略为偏低。在冬季时红蓝比值法反演范围较MOD04_3K AOD的反演范围广;④红蓝比值法AOD在冬春季的北方高反射率地表区域的反演结果精度和反演范围较Himawari-8 AOD产品和MOD04_3K产品有很大优势。     

深蓝算法应用于GF-1 16m相机反演陆地气溶胶

高分一号卫星是我国发展的新一代高分辨率对地观测卫星,如何应用该数据进行环境空气监测是目前迫切需要解决的问题。在深蓝算法基础上,根据GF-1星16 m相机的波段特征,借助MODIS的地表反射率产品去除地表贡献,从蓝波段数据反演了陆地气溶胶,实现了深蓝算法在GF-1星16m相机的应用。在此基础上,收集了2014年8~11月过境北京地区的GF-1星16m相机数据进行了反演实验,结果表明:该算法获取的气溶胶反演结果较好地反映了气溶胶的空间分布。同时,利用同期的AERONET/PHOTONS北京站的地面监测数据进行了算法验证,结果表明,本算法与地面数据有较好的相关性,相关系数大约为0.9,但该算法结果明显高于地面观测结果,可能是MODIS与GF-1星16m相机的波段响应不同导致的结果。     

Estimation of Surface Solar Radiation Using MODIS Satellite Data and RSTAR Model

The MODIS aerosol product and cloud product data are combined with the atmospheric radiation transmission model RSTAR to calculate the surface solar radiation under sunny and cloudy conditions.The results are compared with the ground observed values of Xianghe integrated radiation station.It shows that the simulated value and observed value have good correlation.The R² and RMSE are 0.95 and 38.8 W/m² in the clear skies,while 0.88 and 88.2 W/m² in the cloudy skies.The results show that more cloud\|aerosol mixed states is in Xianghe station,while MODIS can only invert single microphysical parameter of cloud layer,which leads to error of model input parameter,bringing error to the calculation result of surface solar radiation.In order to quantitatively analyze the effect,the RSTAR radiation model was used to calculate the radiance values,and invert f different cloud and aerosol optical thickness,calculating surface solar radiation.The results show that the error of estimation of surface solar radiation is 1.29%~1.56% when the aerosol optical thickness (AOD)is 0.1,compared with the single layer.With the increase of AOD,the effect of AOD increased obviously.The relative error was 17.79%~18.38% when AOD was 1.2.For the heavily polluted areas of North China,it is important to analyze the influence of aerosol on the surface solar radiation under cloud cover,which is very important to improve the calculation accuracy of surface solar radiation under cloud conditions.     

Structural stabilization of EBC with thermal energy reflection at high temperatures

Structural stability of an environmental barrier coating (EBC) with thermal energy reflection function that has a periodic layered structure consisting of Y₂Ti₂O₇ (YT) and Al₂O₃ is essential to maintenance of the EBC performance at high temperatures. The effect of adding Al to YT layer on the structural stability was investigated using model samples in which Al₂O₃ layer was formed on both the YT and Al-doped YT (AYT) substrate by aerosol deposition (AD). Exposure to heat selectively dissipated the Al₂O₃ layer on the YT substrate near the interface between the layer and the grain boundaries of the substrate. In contrast, the Al₂O₃ layer on the AYT substrate remained intact upon heating when Al was added at the solid solution limit. The Al₂O₃ layer was found to exhibit a pronounced degree of (0001) basal plane texture. An increase in the impact velocity of particles during AD effectively developed the basal fiber texture.     

Removal of aerosols by bubbling through porous media submerged in organic liquid

Aerosols can be filtered by passing the carrier gas through a fibrous filter immersed in water (Agranovski, I. E., Myojo, T., & Braddock, R. D. (1999a). Bubble filtering through porous media. Aerosol Science and Technology, 31, 249-257. Using water as the irrigating fluid significantly increases the efficiency of filtration of particles and adds the possibility for simultaneous removal of alien gases from the carrier. Organic compounds (gaseous and particulate) form a significant proportion of pollutants in the atmosphere, and effective purification is needed for ambient air as well as for cleaning exhaust streams. Water does not have a high level of solubility for gaseous organic compounds, and alternative irrigating liquids need to be considered. Experiments were conducted using sunflower oil as the irrigating fluid. The filtration efficiencies of the oil are better than for water, for liquid di-ethyl-hexyl-sebacate particles. As the solubility of organic vapours is much higher in oil compared with the one in water, oil provides an excellent opportunity for utilizing as the irrigating liquid for high-efficient simultaneous removal of organic particles and vapours from air carrier.     

Simultaneous measurement of mass flow rate and charge-to-mass ratio of particles in gas-solids pipe flow

This paper summarizes our research on the theory and application of particle charging in gas-solids pipe flow. The particles moving in a pipe are charged by collisions with the pipe wall. The charge transferred from the particles to the wall per unit time is equal to the electric current flowing from the wall to earth, and the current depends on the mass flow rate and the charge-to-mass ratio. Conversely, these values can be calculated from the electric current using a special technique; i.e., two short pipes that are made of different materials are installed in series with electrical isolation. The principle of the calculation is based on the contact charging between different materials and the charge balance in the system; the simultaneous equations can be solved analytically. This method is applicable to online measurement for polymer powders as well as mineral powders.     

烹饪气溶胶净化方法的研究

经液体吸收剂和固体吸附剂处理，烹饪气溶胶的净化效率可达到９０％左右。     

气溶胶灭火剂pH值测量方法的研究

气溶胶灭火剂作为一种新型灭火剂具有优越的灭火性能，但燃烧后的气溶胶微粒如果酸碱度太强就会腐蚀电路和仪器，所以必需测量出燃烧后的气溶胶的pH值以改良配方，使其酸碱度接近中性，本文就介绍了一套实验装置用来测量气溶胶的pH值，并通过一系列实验数据的分析证明了此种方法的可行性。     

Simulation of aerosol dynamics and transport in chemically reacting particulate matter laden flows. Part I: Algorithm development and validation

To accurately predict aerosol dynamics in various systems, it is imperative to combine the governing equations for transport of momentum, mass and energy as well as reaction kinetics with an accurate procedure for solving the general dynamic equation (GDE). A generalized approach for solution of the GDE based on the discrete-sectional approach in presence of convective and molecular transport is presented. As computational efficiency is an important factor in realistic implementation of such a model, in Part-I of this two-part paper series an adaptive semi-implicit algorithm based on the concept of operating splitting is presented. It is shown that this algorithm is the method of choice for solving the GDE in presence or absence of convective transport based on a discrete-sectional approach.