Nonsphericity and Inhomogenity in Optical Modeling of Sea Salt Aerosols

Sea salt is one of the largest natural aerosol sources in the atmosphere, and it plays an important role in both atmospheric chemical processing and radiative transfer, particularly in the atmosphere over oceans and coastal regions. The research effort presented in Bi et al. (1018) addresses a critical issue associated with the nonsphericity and inhomogenity in optical modeling of sea salt aerosols. Based on the latest invariant imbedding T-matrix method and super-ellipsoidal models, the optical properties of sea salt under various relative humidifies are accurately computed and further compared with either laboratory measurements and field observations. Nonsphericity and inhomogeneity are shown to be key in interpreting laboratory measurements and LiDAR (Light Detection And Ranging) field observations. Figure 1 shows the observed (left) and simulated right) depolarization ratios of sea salts, which strongly depend on the nonsphericity and inhomogeneity of sea salts under different relative humidities. In addition, the effect of inhomogeneity on the asymmetry factor is significant for coarse-mode sea salt aerosols. These findings have important implications for atmospheric radiative transfer and remote sensing involving sea salt aerosols.

Figure 1. The observed depolarization ratios of sea salts (left) and the simulated depolarization ratios of sea salts with different particle models at different humidities (right).  

Reference: 

Bi, L.,W.Lin,Z. Wang, X. Tang, X. Zhang, B. Yi,  2018: Optical modeling of sea salt aerosols: the effects of  nonsphericity and inhomogeneity. Journal of Geophysical Research: Atmospheres, 123, 543-558. https://doi.org/10.1002/2017JD027869