On seasonal and interannual variations in characteristics of atmospheric aerosol optical depth in the region of Tomsk

Multiyear (1995-2018) time series of photometer observations of characteristics of aerosol optical depth (AOD) and columnar water vapor of the atmosphere are used to analyze the specific features of their seasonal and interannual variations, taking into consideration the results, obtained in the last four years. It is noted that the annual AOD behavior persistently exhibits two maxima (in spring and summer periods), mainly attributed to the increased content of fine-mode smoke aerosol. The interannual variations in AOD and in concentration of coarse-mode particles show a statistically significant trend, with the decreases being, on the average, respectively about 0.013 and 0.006 μm3/μm2 per decade.