A large reduction of direct aerosol cooling over Poland in the last decades


Markowicz, K., Zawadzka-Manko, O.; Posyniak, M. A.


This paper presents an analysis of the long-term (1982–2015) variability of aerosol optical properties, as well as aerosol and greenhouse gases (GHG) direct radiative forcing (RF) in central Europe on the basis of MERRA-2 reanalysis and ground-based observation. Calculations of longwave (LW) and shortwave (SW) RF were made with the use of the off-line Fu-Liou radiative transfer model and were preceded by the sensitivity study of the code's input parameters. Then, the long-term mean as well as the annual variability for selected regions of aerosol optical properties and radiative forcing were analysed. The mean AOD trend was −0.056 ± 9% per decade and AOD was reduced by 48% between 1982 and 2015. While for 1982–1990 the trend per decade was −0.12 ± 20%, for 1991–2000 it was −0.17 ± 17% and only −0.02 ± 31% in the last 15 years (2001–2015). The trend of the aerosol radiative forcing (ARF) was 1.52 ± 0.12 W·m−2/10 year and 1.21 ± 0.19 W·m−2/10 year at top of the atmosphere (TOA) and at Earth's surface, respectively. The trend for GHG was significantly smaller and it equalled 0.27 ± 0.01 W·m−2/10 year at TOA and 0.17 ± 0.01 W·m−2/10 year at the surface. Changes in GHG and aerosol direct effect produced additional 3.2 ± 0.2 W·m−2 at TOA, which could be associated with the observed regional climate warming. The change of the direct aerosol effect was about 4 times the GHG RF. The influence of aerosol loading reduction on the radiation budget was significantly higher in the 1990s of the 20th century in comparison to the first decades of the 21st. The effect of aerosol reduction has significant impact on air temperature changes during warm season and negligible during winter.

International Journal of Climatology, 2022, vol. 42(7), pp. 4129-4146, doi: 10.1002/joc.7488

Originally published on - June 13, 2022, 7:50 a.m.
Last update on - June 14, 2022, 1:51 p.m.
Publisher - Sekretariat IGF