A radiometeorological study, part II. An analysis of VHF field strength variations and refractive index profiles

This paper discu sses the cum ulative probability distributions of fi eld strength for four 200 km VHF p at hs in Illin ois in t erm s of a classification of r cfractiv e ind ex profiles. It is shown that exten ded elevated layers produce signal enhance ments of 10 to 25 db a bove the level observed in unstratified conditions. Assuming the layer characteristics given b y rad iosonde data, the bes t agreement between calculated and m easured valu es of fi eld strength is obtained us in g a layer model with a lin ear n-profi le.