MAX-DOAS仪器观测大气Ring效应及对气溶胶参数的敏感性研究

Ring效应是指大气中O_2和N_2分子对太阳光的转动拉曼散射致使太阳夫琅禾费结构变浅(被填充)的现象。大气气溶胶能够改变光子在大气中的光程和大气散射性质,进而影响到光子发生转动拉曼散射的几率(RSP),最终影响填充效应。通过观测RSP在不同气溶胶状态下的变化,可以反演得到气溶胶参量信息。采用地基多轴差分吸收光谱(multi-axis differential optical absorption spectroscopy,MAX-DOAS)方法在晴朗无云天气下对Ring效应进行了观测,并把测量值和模型值进行了对比,两者一致性较好;选取大气辐射传输模型McArtim研究了在不同大气条件下Ring效应对气溶胶参数等的灵敏度,结果表明在大多数测量情况下,气溶胶光学厚度和边界层高度对RSP影响较大,在90°仰角时,AOD从0.1增加到1,RSP减少了24.6%,边界层高度从1km增加到3km,RSP增加了4.4%。研究表明,Ring效应对气溶胶光学厚度和边界层高度较为敏感,这为反演气溶胶的垂直分布提供了一种新方法。

Sensitivity Study of Aerosol Properties from Observation of Atmospheric Ring Effect

Ring effect is defined as the phenomenon that the depth of solar Fraunhofer lines in scattered light is less than those observed in direct sunlight.The aerosol could change the light path and the scattering properties in the atmospheric,and influ-ence Raman Scattering Possibility of the photons,and finally affect the filling-up effect.Aerosol parameters (aerosol optical depth,boundary layer height,single scattering albedo,asymmetric factor)could be obtained by observation of the Ring effect in different aerosol condition.The Ring effect is measured by ground-based MAX-DOAS instrument under clear days and the meas-urement results is compared with McAritim results.The comparison has a good agreement.Radiation transfer model McArtim is used to study the sensitivity of the Ring effect to the aerosol parameters.The study shows that in most conditions,aerosol opti-cal depth (AOD)and boundary layer (bh)height has a great influence to RSP,and in 90 degree elevation angle,RSP has a de-crease of 24.6% when AOD varies from 0.1 to 1,and a decrease of 4.4% when bh varies from 1km to 3 km.The study shows RSP is more sensitive to AOD and boundary layer height,which may provide a new method for aerosol profile.