Possible mechanism of the increase in solar irradiance cloud transmittance and decrease in cloud cover over Europe due to negative trends in sulphate aerosols: a study with the INMCM5 climate modelтезисы доклада
Аннотация:We showed that according to the Era-Interim re-analysis data there is a pronounced effect of cloud transmittance increase over Europe during warm period since the end of 1970s (Chubarova et al., 2020). In this study using the reconstruction model and routine cloud observations we demonstrate that the main reason of these changes is the decrease in low layer cloud cover. At the same time, there is a pronounced negative trend in sulphate aerosol optical thickness over this period in this region. Using INM RAS model with 2 x 1.5 resolution (Volodin et al., 2017) with the aerosol module described in (Volodin and Kostrykin, 2016) we made several numerical experiments for evaluating the possible role of indirect effects of hydrophilic sulphate aerosols on solar irradiance cloud transmittance trends. The influence of different parametrizations of aerosol-cloud-interaction was studied.The results have revealed that during warm period the account for non- direct aerosol effect provides a better agreement in cloud solar irradiance transmittance trends over Europe with those obtained from the Era-Interim reanalysis data. We discussed the possible causes of the observed effects. This research has been supported by the Russian Science Foundation (grant no.20-17-00190).