Comparison of evaporation duct models and microwave transhorizon propagation experiment

Evaporation duct is an anomalous transhorizon propagation environment in marine surface layer. Using evaporation duct model and electromagnetic wave propagation model is the main way to obtain path loss. The model proposed by Paulus and Jesk and another model established originally by American Naval Postgraduate School (NPS) are the most widely used, which are called the PJ model and NPS model, respectively. Based on the nearly seven months meteorological and oceanographic (METOC) parameters measurements on a sea platform, the two evaporation duct models are compared. Meantime, using nearly one month propagation experiment data, the relative performance of the two evaporation duct models in propagation path loss computation is compared under different environmental conditions. The results indicate: 1) both of the two evaporation duct models performed reasonably well in unstable atmospheric condition, the evaporation duct heights predicated by NPS are usually lower than PJ. In stable atmospheric conditions, the two models are vastly different; 2) using the single point hydrological meteorological measurements, NPS model is better than PJ model in path loss prediction, especially in unstable atmospheric condition; 3) based on the cumulative median path loss distribution, the PJ and NPS model differences are –14.02 dB and –10.06 dB, respectively. The results are helpful for the path loss prediction in microwave transhorizon propagation and the planning programming in radio communication system in marine and coastal zones.