沙尘、黑碳和有机碳气溶胶吸收光学厚度的分离算法研究

Mineral dust, black carbon (BC), and organic carbon (OC) aerosols are the three main types of light-absorbing aerosols, which can change atmospheric radiation balance and affect regional and global climate through direct, indirect, and semi-direct effects.Until recently, there are very few studies about that mineral dust, BC and OC aerosol contribution to the total absorption optical depth, respectively, which is one of the uncertain factors that assessment climate change. In this project, sun photometer measurements will be used to develop a new approach to partition the absorption optical depth of the mineral dust, BC, and OC aerosols from the total absorptive optical depth.First, we will derive the optical characteristics exponential equations of the absorptive aerosols based on the relationships between optical depth and wavelengths.Second, by using sun photometer data measured from the dust area, biomass burning area, and fossil fuel combustion area, we will estimate the Angstrom index of the light-absorbing optical depth.Third, the column absorption optical depth of mineral dust, BC and OC aerosols can be partitioned from the total column absorption optical depth by solving the exponential equations.We will further analyze the source of errors, compare the results with other instruments, and validate our approach. One of the advantages of the new approach is that it can be applied directly to the sites which have the measurements by the sun photometer.Lastly, by using the Monte Carlo radiative transfer model (MACR), we can get the radiative forcing and heating rate of the mineral dust, BC, and OC aerosols in the East Asian region with a combination of this new approach and satellite data.

吸收性气溶胶主要包括沙尘、黑碳和有机碳气溶胶，可通过直接、间接及半直接效应改变大气辐射收支平衡影响区域和全球气候。到目前为止，利用观测资料开展沙尘、黑碳和有机碳气溶胶对总吸收光学厚度贡献的研究较少，这是造成气候评估不确定的因素之一。本项目拟利用多波段太阳光度计资料发展一套分离沙尘、黑碳和有机碳气溶胶整层吸收光学厚度的新方法。该方法从光学厚度同波长指数关系的方程入手，推导出吸收性气溶胶光学特征的方程组；分析沙尘区、生物质燃烧区和化石燃料区的太阳光度计资料，获得吸收光学厚度Angstrom指数，进而求解方程组分离出沙尘、黑碳和有机碳气溶胶整层吸收光学厚度；将结果同其他观测仪器资料进行对比和验证并分析误差的来源；新方法的一个优点是可直接应用于现有大量的太阳光度计观测站点。在此基础上，结合卫星资料，利用蒙特卡洛辐射传输模式，获得东亚地区沙尘、黑碳和有机碳气溶胶的辐射强迫和大气加热率。

吸收性气溶胶主要包括沙尘、黑碳和有机碳气溶胶，可通过直接、间接及半直接效应改变大气辐射收支平衡，进而影响区域和全球气候，是评估气候不确定性的关键因素之一。在本项目的资助下，主要研究成果有：从光学厚度同波长指数关系的光学方程入手，推导出吸收性气溶胶光学特征的方程组，进而利用多波段太阳光度计资料发展了一套分离沙尘、黑碳和有机碳气溶胶整层吸收光学厚度的新方法；通过分析沙尘区、生物质燃烧区和化石燃料区的资料，初步分析了吸收性气溶胶的主要来源；为了克服单一沙尘识别方法的缺点，进而提出了使用主动（激光雷达）和被动遥感技术（可见光近红外技术、热红外技术和微波遥感技术）相结合识别沙尘气溶胶的系统概念模型；估算了中国地区行星边界层高度，进一步评估了中国地区不同季节、不同地表类型对边界层厚度的影响；利用激光雷达资料识别了人为沙尘气溶胶；估算了沙尘、烟尘型气溶胶的海洋和陆地类型下天顶处（TOA）和地表处（Surface）的辐射强迫。