[The graph shows reflectivity also decreased with a decrease in solar radiation during the eclipse]
We have no conclusive evidence as to what caused the reflectivity in the boundary layer. It could be insects and birds, or it could be refractive index perturbations. In either case it is evident that the decrease of solar radiation decreased the reflectivity. At the time we felt that the surface heat flux was responsible for thermal plumes that generated the refractive index perturbations that reflected the radar emissions.