Comparison of maritime measurements of 2 with NAVSLaM model predictions.

In this paper, a study is made of the refractive index structure parameter 2, as derived from angle-of-arrival (AOA) measurements made on the beam after propagation along a 16 km slant path across the Chesapeake Bay. These measurements are compared with 2 estimates derived from the Navy Atmospheric Vertical Surface Layer Model (NAVSLaM), which are based upon prevailing meteorological conditions. Correlation coefficients for the reported data vary between 0.64 and 0.9. Despite the Chesapeake Bay theoretically being a difficult location for employing a Monin-Obukhov similarity theory-based model such as NAVSLaM, the agreement between the AOA 2 measurements and the NAVSLaM 2 estimates was, in many cases, good. A possible explanation of this agreement between the modeled and measured 2 values is that the large air-water temperature differences encountered provided such strong forcing for the NAVSLaM model that any potential violations of the Monin-Obukhov similarity theory assumptions had only a secondary influence on the 2 estimates.