Coastal atmospheric effects on microwave refractivity

Abstract : Sharp vertical gradients within thermodynamic profiles in the atmospheric boundary layer (BL) create abrupt changes in refractivity, thereby impacting electromagnetic (EM) wave propagation. This study uses NRL's Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS(trademark)) to investigate refractive structure during a field experiment conducted at Wallops Island, VA. Measurements include low-elevation radar frequency pathloss, meteorological conditions (e.g., from buoys, rocketsondes, helicopter profiles), and radar clutter returns. EM propagation codes are useful for naval operations and decision-making; when supplied with accurate refractivity fields, they produce radar coverage diagrams. The fidelity of COAMPS(trademark) refractivity analyses/forecasts, and their usefulness as input to microwave propagation codes, is evaluated here in a complex littoral setting.