Range-dependent evaporation duct height estimation from a versatile ship-mounted X-band receiving array

As low-altitude atmospheric refractive conditions significantly affect the shipboard radars and radio communication conditions in the maritime environment, characterizing marine atmospheric boundary layer properties, ducting in particular, is thus crucial for air-sea interaction research. The CASPER-East at-sea experimental campaign conducted off the coast of Duck, NC, during October-November of 2015, provided an opportunity to measure EM propagation. A key part of the EM measurements is a specially designed X-band receiving array, which is deployed to measure the one-way propagation loss between emitters and receivers as a function of antenna height and range. The collected data from the receiving array at multiple ranges is be used to invert for the range-dependent evaporation duct height (EDH) by comparing with a library of propagation curves generated using the parabolic wave equation. The estimated EDH vs. range is compared with predictions from NAVSLaM using concurrent environmental measurements as input. The results show that EDH varies with range and time during data collection.