## 4 Summary and Conclusions  
In the present study, a new version of the spectral FORTH RTM, which is vertically resolved and takes into account 3-D distributions of aerosols and other atmospheric parameters, was run at high spatial (0.5\({}^{\circ}\)\(\times\) 0.625\({}^{\circ}\)) and temporal (3-hourly) resolution to investigate in detail the three-dimensional distributions of the SW direct radiative effect of an intense African dust episode (DAEC) that took place from 16 to 18 June 2016 over the central and eastern MB. The model ran under all-sky conditions accounting for analytical profiles of cloud and aerosol optical properties, using data from the satellite ISCCP-H and MERRA-2 reanalysis databases, respectively. Running with all aerosols, and all except for dust, the RTM estimated the SW fluxes at the TOA, in the atmosphere, at the Earth's surface, as well as at 50 levels in the atmosphere, and estimated from their difference the corresponding dust DREs (DDREs). The model fluxes at the TOA and at the Earth's surface were evaluated against satellite (CERES-SYNOP) and ground (BSRN) measurements, respectively. In addition, the model estimated the vertically resolved atmospheric heating rates induced by the dust absorption of solar radiation, i.e., the atmospheric SW DDRE, and also quantified their contribution to the modification of the atmospheric lapse rates, which exhibited reduced temperature gradients and temperature inversions over the Mediterranean areas affected by the African dust transport. Finally, the model quantified the buoyancy produced by the SW atmospheric DDRE, as well as the consequent modification of the vertical velocity, which is important for the mixing of energy and cloud formation. All these aspects of the present work offer an unprecedented highly spatially (horizontally and vertically) and temporally (3-hourly) resolved assessment of the direct SW radiative effects of dust under episodic conditions over the climatically sensitive Mediterranean Basin, regarded as a climate change hotspot. The main conclusions of the current study are summarized below. * The RTM-estimated SW fluxes are reliable, giving confidence in the obtained DDREs. Specifically, during the 3 days of the examined DAEC (from 16 to 18 June 2016), the model fluxes at the TOA and at the Earth's surface compared well against CERES and BSRN data, respectively, achieving a reasonable closure of the SW radiation budget. The 3-hourly matched pairs yield overall correlation coefficients equal to 0.98 and 0.88, and relative biases equal to 0.8 and 3.5%, against CERES and BSRN, respectively. Based on this uncertainty of the RTM solar fluxes, the modeled DDREs have an uncertainty smaller than 7%. * The model input MERRA-2 dust optical properties, in particular the optical depth, agrees reasonably well against reference data from AERONET stations located in areas affected by the transported African dust. MERRA-2 successfully reproduces the intra-daily variation in the dust aerosol loads, representing the spread of the dust outbreak over the central and eastern MB and its gradual eastward shift during the 3-day period (16-18 June 2016) of the examined DAEC. * Dust aerosols cause a significant solar atmospheric radiative heating over areas undergoing the African dust export, extending from northern Africa to as far as the northern Balkans and the Black Sea. The SW atmospheric DDRE is maximum (values up to 187 W/m\({}^{2}\) at 12:00 UTC or 72 W/m\({}^{2}\) on a daily mean basis) over locations with the maximum dust loadings. Respectively, over these heavily dust loaded areas, DAs also induce a significant surface radiative cooling, with maximum values equal to 200 W/m\({}^{2}\) at 12:00 UTC and 62 W/m\({}^{2}\) on a daily mean basis.