Size Distribution and Depolarization Properties of Aerosol Particles over the Northwest Pacific and Arctic Ocean from Shipborne Measurements during an R/V Xuelong Cruise
- Institute of Atmospheric Physics/CAS , LAPC, Beijing, China (panxiaole@mail.iap.ac.cn)
Atmospheric aerosols over polar regions have attracted considerable attention for their pivotal effects on climate change. In this study, temporospatial variations in single-particle-based depolarization ratios (δ: s-polarized component divided by the total backward scattering intensity) were studied over the Northwest Pacific and the Arctic Ocean using an optical particle counter with a depolarization module. The δ value of aerosols was 0.06 ± 0.01 for the entire observation period, 61 ± 10% lower than the observations for coastal Japan (0.12 ± 0.02) (Pan et al. Atmos. Chem. Phys. 2016, 16, 9863−9873) and inland China (0.19 ± 0.02) (Tian et al. Atmos. Chem. Phys. 2018, 18, 18203−18217) in summer. The volume concentration showed two dominant size modes at 0.9 and 2 μm. The super-micrometer particles were mostly related to sea-salt aerosols with a δ value of 0.09 over marine polar areas, ∼22% larger than in the low-latitude region because of differences in chemical composition and dry air conditions. The δ values for fine particles (<1 μm) were 0.05 ± 0.1, 50% lower than inland anthropogenic pollutants, mainly because of the complex mixtures of sub-micrometer sea salts. High particle concentrations in the Arctic Ocean could mostly be attributed to the strong marine emission of sea salt associated with deep oceanic cyclones, whereas long-range transport pollutants from the continent were among the primary causes of high particle concentrations in the Northwest Pacific region.
How to cite: Pan, X., Tian, Y., Yan, J., Lin, Q., Sun, Y., Fu, P., and Wang, Z.: Size Distribution and Depolarization Properties of Aerosol Particles over the Northwest Pacific and Arctic Ocean from Shipborne Measurements during an R/V Xuelong Cruise, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13205, https://doi.org/10.5194/egusphere-egu2020-13205, 2020