Generalization of Results of Atmospheric Aerosol Optical Depth Measurements on Spitsbergen Archipelago in 2011–2016

Resumo

We discuss the results of spectral measurements of aerosol optical depth (AOD) of the atmosphere, carried out in warm periods of 2011–2016 in the Arctic settlement Barentsburg (Spitsbergen Archipelago). The statistical characteristics of seasonal and interannual variations in atmospheric AOD in the wavelength range of 0.34–2.14 μm are presented. The average AOD (0.5 μm) over the six-year period of observations had been 0.086, and, in particular, the fine mode AOD component had been 0.062 and the coarse mode AOD component had been 0.024. It is shown that the seasonal variations were best manifested in the decrease of modal (most probable) values of fine mode AOD component from 0.055 in spring to 0.025 in autumn. As compared to the preceding (pre-2011) period, we noted a closer convergence in the average AOD values between spring and summer, primarily due to a decrease in the content of fine mode aerosol in spring and its increase in summer. The summertime AOD growth is most likely due to episodic outflows of smoke aerosol from boreal zones of Eurasia and North America.