Aerosol optical depth assimilation for a modal aerosol model: Implementation and application in AOD forecasts over East Asia
Aerosol optical depth assimilation for a modal aerosol model: Implementation and application in AOD forecasts over East Asia
复制标题
模态气溶胶模型的气溶胶光学深度同化：在东亚 AOD 预报中的实施和应用
DOI：
10.1016/j.scitotenv.2020.137430
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发表时间：
2020
影响因子：
9.8
通讯作者：
Chang Ming
中科院分区：
文献类型：
--
作者：
Pang Jiongming;Wang Xuemei;Shao Min;Chen Weihua;Chang Ming
在网格点统计内插三维变分系统（Gridpoint Statistical Interpolation 3DVAR）中，建立了一个新的气溶胶光学厚度（AOD）数据同化模块FastJ/CRTM-AOD DA。并将其应用于气象研究与预报/化学模式（WRF/Chem）中的欧洲模态气溶胶动力学模式（MADE/SORGAM）和二次有机气溶胶模式（SORGAM）。采用WRF/Chem的Fast-J光学组件作为AOD的观测算子。相应的雅可比码是对GSI中CRTM-AOD的雅可比码进行修改的。这种方法避免了雅可比码生成的需要，这是复杂的和困难的高度非线性观测算子。在研究期间（2014年1月和4月），与地面AOD观测相比，AODA减少了约20%的分数误差（FE）与MADE/SORGAM。应用于戈达德化学气溶胶辐射和传输（GOCART）机制的原始DA框架，在低值AOD情况下（值< 0.4），表现略好于新的同化方案。然而，与原始DA框架相比，新的DA方案在高值（0.4 < value ≤ 1.2）和极高值（value > 1.2）AOD情况下表现出显著的改进。FE可分别减少48%和64%。结果表明，不同气溶胶机制下，气溶胶光学厚度变化对气溶胶光学厚度预报的影响有显著差异。此外，FastJ/CRTM-AOD DA模块可以方便、有效地应用于其他气溶胶方案和其他光学模块，这对AOD同化的发展具有重要意义。
A new aerosol optical depth (AOD) data assimilation (DA) module was developed in Gridpoint Statistical Interpolation (GSI) 3-dimensional variational (3DVAR) system, named FastJ/CRTM-AOD DA module. And applied to the Modal Aerosol Dynamics Model for Europe with the Secondary Organic Aerosol Model (MADE/SORGAM) in the Weather Research and Forecasting/Chemistry model (WRF/Chem). The Fast-J optical module in WRF/Chem was used as the observation operator of AOD. The corresponding Jacobian code was modified from the one of CRTM-AOD in GSI. This way obviated the need for the Jacobian code's generation, which was complex and difficult for the highly nonlinear observation operator. During the studying period (January and April of 2014), compared to the ground AOD observations, AOD DA reduced about 20% fractional error (FE) with MADE/SORGAM. The original DA framework, which applied to the Goddard Chemistry Aerosol Radiation and Transport (GOCART) mechanism, performed slightly better than the new assimilation scheme for the low-value AOD situations (value < 0.4). However, compared to the original DA framework, the new DA scheme show a notable improvement for the high-value (0.4 < value ≤ 1.2) and extreme-high-value (value > 1.2) AOD situations. FE can be reduced by 48% and 64%, respectively. It indicates that the AOD DA impacts on AOD forecasts vary significant between different aerosol mechanisms. Moreover, FastJ/CRTM-AOD DA module can be easily and efficiently applied to the other aerosol schemes and the other optical modules, which is important to the development on AOD assimilation.