The impact of large-eddy simulation grid resolution on electromagnetic wave propagation in the presence of a cloudy boundary layer

In this work, the propagation of electromagnetic waves in realistic turbulent media is studied. Combining large eddy simulation (LES) for generating the largest scales of the medium – the resolved scales – and stochastic processes for the smallest scales – the sub-grid scales – extended LES (X-LES) allows to generate large and realistic domains of turbulent atmosphere. In this work, we focus on the size of the smallest resolved scales and its impact on an X-band electromagnetic wave propagating in the medium. This impact is studied via numerical simulations of a 10-GHz spherical wave propagating through 95 km of turbulent media generated with X-LES and for different resolved scales. The considered medium is a convective marine layer for which turbulence is known to be strong. Our study shows that the choice of the resolved scale for this type of medium has a significant impact on the expected wave attenuation, despite the fact that the total spectrum of the turbulent medium does not depend on this parameter.