Given the escalating impacts of climate change, the shift towards more resilient and sustainable energy systems is essential. This higher reliance in renewable energy sources, such as solar power, demands greater accuracy in forecasting changes in weather conditions. This research introduces a novel technique to enhance the accuracy of current solar radiation forecasts on stratocumulus days, by combining satellite observations and large-eddy simulations (LES). Two methods were proposed and implemented in DALES to study the evolution of the cloud field: (i) an advection-only scheme, disregarding all physical processes except horizontal advection, and (ii) standard LES, with application of nudging during the spin-up period of the model.

The implementation of the advection-only model in DALES demonstrated that this approach is not completely successful in isolating the role played by horizontal advection from the remaining physical processes commanding cloud evolution. The rise of non-zero subfilter-scale turbulent fluxes throughout the boundary layer was observed, suggesting diffusion of the thermodynamic fields. In the standard LES runs, the application of nudging (using time scales of 60s and 300s) during the spin-up period of the model fulfilled its intention of keeping a mean thermodynamic state close to the initially prescribed vertical profiles. Nonetheless, this has shown to compromise the development of turbulence in the system, especially in the sub-cloud layer, leading to an underestimation of the turbulent fluxes in the model for this region. Analysis suggested that initialising DALES with vertical profiles for the thermodynamic quantities showing zero mean vertical gradients in the boundary layer are a plausible justification for the results obtained, as this would lead to reduced variances of the thermodynamic quantities and a subsequent underestimation of the turbulent fluxes observed.

Despite the great agreement shown between the vertical profiles coming from ground-based and satellite observations, using the technique proposed in this research, and the radiosonde measurements, one of the main conclusions from this research is the need to continue exploring the application of nudging. This includes performing test simulations with a wide range of parameters commanding nudging (e.g. spin-up duration or nudging time scale), and with the prescription of initial vertical profiles exhibiting some curvature in the boundary layer to allow for an increase in the variances of the thermodynamic quantities in the domain. As findings revealed that a genuine horizontal advection using DALES was not attained, the usage of the current advection-only module in DALES is not recommended, and further research is advised until turbulent effects are completely mitigated.