A seven-years based characterisation of aerosol light scattering properties at Central European rural site: Variability and Source apportionment

0561600 - ÚVGZ 2023 GR eng A - Abstrakt
Suchánková, Lenka - Mbengue, Saliou - Zíková, Naděžda - Ondráček, Jakub - Šmejkalová Holubová, A. - Holoubek, Ivan - Ždímal, Vladimír - Prokeš, Roman
A seven-years based characterisation of aerosol light scattering properties at Central European rural site: Variability and Source apportionment.
Abstract Book. Athens. 2022, č. článku ATAS-14-05..
[International Aerosol Conference IAC 2022. 04.09.2022-09.09.2022, Athens]
Grant CEP: GA MŠMT(CZ) LM2015037
Institucionální podpora: RVO:86652079 ; RVO:67985858
Klíčová slova: aerosols * scattering properties of aerosols * temporal variability * source apportionment * radiative forcing * climate change * national atmospheric observatory košetice
Obor OECD: Meteorology and atmospheric sciences; Meteorology and atmospheric sciences (UCHP-M)
https://iac2022.gr/abstracts/

Atmospheric aerosols have a significant impact on the radiative forcing of Earth's climate, directly through the aerosol-radiation interactions (ARIs), i.e., scattering or absorption of incoming solar and outgoing infrared radiation, or indirectly through the aerosol-cloud interactions (ACIs)1,2. Although there are studies addressing aerosol impact on local climate3–5, the information on long-term measurements at rural background site is missing. Such studies are important for understanding of local sources and long-range transport of both anthropogenic and natural aerosols. Therefore, we focused on temporal variations of the total light scattering (σsp) and backscattering (σbsp) coefficients and associated optical properties such as the Ångstrӧm exponent (SAE), backscattering ratio (b), and asymmetry factor (g) at a rural background site National Atmospheric Observatory Košetice (NAOK, 49°34'20.787N, 15°4'48.155E') in Central Europe. We measured σsp and σbsp at 5 min resolution at three wavelengths (450, 550, and 700 nm) using the Integrating Nephelometer TSI 3563 (PM10 inlet). Measurements were performed from 16 August 2012 to 31 December 2019. The analysis has been performed using R software version 4.1.0. The preliminary results show that the overall trend for both σsp and σbsp is downward from 2012-to 2019, the slope of the median trend line was -2.50 Mm-1/yr and -0.18 Mm-1/yr at 550 nm, respectively. SO2 and NOx concentrations were well correlated with σsp and σbsp throughout the period, confirming their contribution in the light-scattering enhancement. b had a positive slope of the median trend line (0.012/yr), indicating more efficient cooling effect alongside lower aerosol loading. Both σsp and σbsp reached higher values in the cold seasons (median, 46.8 and 5.9 Mm-1) than in the summer (median, 25.4 and 4.1 Mm-1). This phenomenon is probably related to the higher aerosol loading in winter due to higher energy consumption, poorer dispersion of pollutants, and lower planetary boundary layer. Elevated SAE observed in summer indicates smaller particles and corresponds to secondary organic aerosol. On the other hand, decreased SAE during winter corresponds to bigger particles (higher atmospheric stability and thus aerosol aging).
In addition, the sources of scattering aerosols, chemical composition, meteorological conditions, particle size distribution, and radiative forcing will be further investigated at NAOK to better understand the direct effects of aerosols on local climate.

Trvalý link: https://hdl.handle.net/11104/0334177