Modeling turbulence effects on radar wave propagation over sea

Vertical profiles of the modified refractivity and turbulence strength at microwave band are given based on the similarity theory in marine surface layer.The instantaneous random index of refraction is simulated based on onedimensional Kolmogorov spectrum，and the vertical profile of the modified refractivity with turbulent perturbation is built by adding the random index of refraction to the modified refractivity at each altitude.The integrated effects of evaporation duct and turbulence on radar wave propagation and radar performance are modeled by using the advanced propagation model（APM)based on sea surface observations.It is found that turbulence effects make radar wave propagation losses obviously increased in evaporation duct， and hence degrade the ability for overhorizon detection， but make propagation losses decreased to some extent over evaporation duct.It is necessary to consider the integrated effects of evaporation duct and turbulence in marine surface layer in order to quantitatively evaluate the performance of the shipboard radar.