Influence of the vertical absorption profile of mixed Asian dust plumes on aerosol direct radiative forcing over East Asia
Influence of the vertical absorption profile of mixed Asian dust plumes on aerosol direct radiative forcing over East Asia
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DOI：
10.1016/j.atmosenv.2016.04.044
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发表时间：
2016-08
影响因子：
5
通讯作者：
Y. Noh;Kwonho Lee;Kwanchul Kim;Sung-Kyun Shin;D. Müller;Dongho Shin
中科院分区：
文献类型：
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作者：
Y. Noh;Kwonho Lee;Kwanchul Kim;Sung-Kyun Shin;D. Müller;Dongho Shin
利用圣巴巴拉离散纵坐标大气辐射传输（SBDART）程序，计算了东亚混合尘埃羽在0.25 ~ 4.0μm太阳波长范围内的气溶胶直接辐射强迫（ADRF）和加热率廓线。利用多波长拉曼激光雷达系统测量了大气气溶胶消光系数和单次散射峰（SSA）的垂直分布。这些数据被用作我们的辐射传输计算的输入参数。我们考虑了SBDART中的四种辐射强迫情况：1。灰尘，2.污染，3。混合尘羽和SSA垂直剖面的使用，和4。混合尘埃羽流和SSA的列平均值的使用。在我们的敏感性研究中，我们研究了SSA和气溶胶层高度对我们的结果的影响。在地面和大气中的ADRF显示出一个小的依赖于气溶胶消光垂直廓线的具体形状和它的光吸收特性的所有四种情况。相反，在大气顶部（TOA），ADRF很大程度上受气溶胶消光的垂直分布的影响。如果气溶胶的光吸收能力（SSA的减少）增加，则该效应增加。我们发现不同的辐射效应的情况下，两层气溶胶有不同的光吸收特性。最大的差异被观察到在TOA的吸收气溶胶层在高海拔地区，在这种情况下，我们认为在一种情况下，SSA的垂直廓线，在另一种情况下，列平均SSA只。当吸光气溶胶层位于3 km以上高度时，TOA处的ADRF增加。从激光雷达数据中获得的高度分辨SSA与总层平均SSA之间的差异表明，使用层平均SSA可能会产生相当大的误导，因为它会在TOA处的ADRF计算中引起较大的误差，进而可能导致加热率垂直剖面的误差。
We estimate the aerosol direct radiative forcing (ADRF) and heating rate profiles of mixed East Asian dust plumes in the solar wavelength region ranging from 0.25 to 4.0μm using the Santa Barbara Discrete Ordinate Atmospheric Radiative Transfer (SBDART) code. Vertical profiles of aerosol extinction coefficients and single-scattering albedos (SSA) were derived from measurements with a multi-wavelength Raman lidar system. The data are used as input parameters for our radiative transfer calculations. We considered four cases of radiative forcing in SBDART: 1. dust, 2. pollution, 3. mixed dust plume and the use of vertical profiles of SSA, and 4. mixed dust plumes and the use of column-averaged values of SSA. In our sensitivity study we examined the influence of SSA and aerosol layer height on our results. The ADRF at the surface and in the atmosphere shows a small dependence on the specific shape of the aerosol extinction vertical profile and its light-absorption property for all four cases. In contrast, at the top of the atmosphere (TOA), the ADRF is largely affected by the vertical distribution of the aerosols extinction. This effect increases if the light-absorption capacity (decrease of SSA) of the aerosols increases. We find different radiative effects in situations in which two layers of aerosols had different light-absorption properties. The largest difference was observed at the TOA for an absorbing aerosol layer at high altitude in which we considered in one case the vertical profile of SSA and in another case the column-averaged SSA only. The ADRF at the TOA increases when the light-absorbing aerosol layer is located above 3 km altitude. The differences between height-resolved SSA, which can be obtained from lidar data, and total layer-mean SSA indicates that the use of a layer-mean SSA can be rather misleading as it can induce a large error in the calculation of the ADRF at the TOA, which in turn may cause errors in the vertical profiles of heating rates.