## 5 Conclusions  
In this work, the direct radiative effect of aerosols and tropospheric NO\({}_{2}\) on SSR is estimated under different sky conditions, along with the radiative effect of different cloud types (liquid and ice), focusing on 16 locations in Greece, in the Eastern Mediterranean. For the scopes of this study, the latest release of various satellite and climatological products is used for the period 2005-2019. The core data are aerosol, cloud, water vapor, and tropospheric/stratospheric NO\({}_{2}\) satellite observations from the MODIS/Aqua C6.1 MYDATML2 and the OMI/Aura QA4 ECV v1.1 product. These, and the rest of the datasets, were gridded on a monthly basis at a standard 0.125\({}^{\circ}\)\(\times\) 0.125\({}^{\circ}\) grid covering the Eastern Mediterranean. The gridded data over the 16 locations are used as the input in a system that was developed based on the SBDART radiative transfer model. The original SBDART code is updated here (SBDART-NO\({}_{2}\)) so as to account for the absorption of NO\({}_{2}\) in the UV/Vis, and for the tropospheric and stratospheric NO\({}_{2}\) profiles. The main findings of this study are summarized in the following:  
* Our monthly SSR simulations are in good agreement with the ground-based observations from three stations with quality-assured long time series (underestimation of \(-\)14.5 W/m\({}^{2}\) or \(-\)7.5% with a very good correlation) and two satellite products, CM SAF SARAH-2.1 (\(-\)9.1%) and CERES EBAF edition 4.1 (\(-\)7.2%);
* The annual all-sky radiative effect of aerosols (RE\({}_{\rm aer}\)) and tropospheric NO\({}_{2}\) (RE\({}_{\rm NO2}\)) on SSR for the 16 locations in Greece is \(-\)13 W/m\({}^{2}\) and \(-\)0.074 W/m\({}^{2}\), respectively. Liquid clouds dominate, with an average RE\({}_{\rm lc}\) of \(-\)36 W/m\({}^{2}\), and ice clouds follow (RE\({}_{\rm ic}\) of \(-\)19 W/m\({}^{2}\)). RE\({}_{\rm NO2}\) is smaller, by two orders of magnitude, compared to that of aerosols and clouds, and hence is negligible;
* On average, higher annual RE\({}_{\rm aer}\) values (by \(\sim\)2 W/m\({}^{2}\)) appear over urban locations compared to rural locations. The annual RE\({}_{\rm aer}\) ranges from \(-\)18 W/m\({}^{2}\) (Patras) to \(-\)8 W/m\({}^{2}\) (Olympus). The annual RE\({}_{\rm NO2}\) over urban locations (\(-\)0.113 W/m\({}^{2}\)) is double the ones over rural locations, with the highest values appearing over the three pollution hot spots in the area, namely, Athens (\(-\)0.166 W/m\({}^{2}\)), Kozani (\(-\)0.144 W/m\({}^{2}\)), and Thessaloniki (\(-\)0.118 W/m\({}^{2}\)). The annual RE\({}_{\rm lc}\) ranges spatially from \(-\)79 W/m\({}^{2}\) (Olympus) to \(-\)21 W/m\({}^{2}\) (Rhodes), while RE\({}_{\rm ic}\) ranges from \(-\)26 W/m\({}^{2}\) (Ioannina) to \(-\)13 W/m\({}^{2}\) (HCMR);
* The annual average RE\({}_{\rm aer}\) for all the locations under clear skies (\(-\)18 W/m\({}^{2}\)) is about 3-4 times larger than for liquid (\(-\)5 W/m\({}^{2}\)) and ice (\(-\)6 W/m\({}^{2}\)) cloud-covered skies; for individual locations, it can be up to 4-5 times larger (e.g., Olympus). For tropospheric NO\({}_{2}\), the average RE\({}_{\rm NO2}\) under clear skies (\(-\)0.095 W/m\({}^{2}\)) is double that for liquid (\(-\)0.045 W/m\({}^{2}\)) and ice (\(-\)0.051 W/m\({}^{2}\)) cloud-covered skies;
* RE\({}_{\rm aer}\) peaks in the spring and summer, with the maximum values (up to \(-\)30 W/m\({}^{2}\) for some locations) appearing in August over all the 16 locations. During the winter, especially in December and January, RE\({}_{\rm aer}\) generally drops below \(-\)5 W/m\({}^{2}\) and in some cases reaches values around \(-\)1 W/m\({}^{2}\). RE\({}_{\rm NO2}\) peaks in July, with the highest values appearing over Athens (\(-\)0.215 W/m\({}^{2}\)), which is still very low to play a substantial role in the local radiative budget;* The lowest \(\rm RE_{\rm lc}\) (\(-1\) W/m\({}^{2}\)) appears in July over Rhodes, and the highest \(\rm RE_{\rm lc}\) (\(-123\) W/m\({}^{2}\)) appears in May over Olympus.