Evaluation of COAMPS Driven Electromagnetic Propagation Modeling Using Field Campaign Measurements

The marine atmospheric surface layer (MASL) is a dynamic environment with variations in both oceanic and atmospheric variables that significantly alter near surface refractivity gradients resulting in anomalous radio frequency (RF) propagation. As a result of this anomalous RF propagation, the range of ship-mounted electromagnetic sensors could significantly vary from expected values leading to detection errors or unexpected performance. Obtaining critical near surface atmospheric measurements is particularly challenging due to waves and sea spray. In the absence of available atmospheric measurements, the Navy uses mesoscale numerical weather prediction (NWP) systems to estimate near surface atmospheric gradients in this environment. an important tool the Navy uses. The primary NWP system used by the Navy is the Coupled Ocean Atmosphere Mesoscale Prediction System (COAMPS®
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) which is commonly blended with the Navy Atmospheric Vertical Surface Layer Model (NAVSLaM) to obtain finer resolution near the surface, allowing for improved resolution of features such as evaporative ducts, which can be challenging for COAMPS to resolve on its own. These NWP predictions are fed into RF propagation simulations such as the Variable Terrain Radio Parabolic Equation computer model (VTRPE), the Advanced Propagation Model (APM), and the Tropospheric Electromagnetic Parabolic Equation Routine (TEMPER) to obtain estimates of the refractive environment.