Study of the vertical variability of aerosol properties based on cable cars in-situ measurements

This work presents the methodology for obtaining the vertical profiles of aerosol optical and microphysical properties based on cable-car and ground-based measurements in a mountain region. The presented data were collected during the winter workshop between 7th and 13th March 2016 in Krynica-Zdroj (southern Poland). During this campaign photoacoustic instruments were used to observe the single-scattering optical properties at two sites with a vertical separation distance of about 360 m. The micro-aethalometer AE-51 and the optical particle counter OPC-N2 were mounted on the cable car and used to measure profiles of black carbon concentration and aerosol size distribution. The mean extinction coefficients at the upper (37 Mm−1) and lower (43 Mm−1) sites were about three times lower than the long-term average for this season due to weather conditions, which did not favour the haze conditions. However, a significant correlation between temperature gradient and difference of extinction coefficient between the valley and mountain was found. During nights and stable thermodynamic conditions the values in the valley were higher than close to the top of the mountain. Profiles obtained from cable car measurements shown significant reduction of black carbon and aerosol concentration with altitude also during the day time. In addition, the effective radius, and the fine and coarse mode aerosol concentration was slightly changed with altitude when the relative humidity was below 100%. During condensation and cloud formation the significant variability in particles effective radius were found as a result of aerosol activation close to the top of the mountains.