Seasonal results of aspect sensitivity from an MF radar over Kunming (25.6°N, 103.8°E), China

The physical shapes and causes of these partial reflection scatterers for MF radar is, as yet, an unsolved question. The aspect sensitivity parameterized by a quantity θ_S is defined often as the rate of decrease of power as a function of angle. Small values of θ_S imply the existence of specular scatterers. The seasonal results of aspect sensitivity from Kunming MF radar have been studied based on the first 12 months data, which shows a clear seasonal dependence with the bigger values in winter and the smaller values in summer. Aspect sensitivity also presents an evident variation in height, increasing between 80 and 90 km while decreasing from 90 to 100 km. Turbulence velocity measured during the same period supports the proposal that turbulences play an important role in causing specular scatterers which produces aspect sensitivity in D-region for MF radar.