Development and Experimental Evaluation of Oceanic Evaporation Duct Models Based on the LKB Approach

摘要

Comparison is made between four evaporation duct models based on the surface layer theory of Liu, Katsaros and Businger. These models are used to generate modified refractivity (M) profiles that are then compared with those determined from time-averaged atmospheric data measured by the JHU/APL profiling buoy. Model inputs are derived from measurements from masts on the R/V CHESSIE and a tethered sea-surface temperature (SST) buoy. Because electromagnetic propagation is critically dependent on the M profile slopes, different analytical techniques are employed to compare the curvature of the model profiles with that of the profiles measured by the profiling buoy. When root- mean-square M slope difference between model and a curve fit to the data is used as the comparison criterion, the NPS model performs the best for stable and near-neutral conditions, while the BYC model performs the best for unstable conditions. When root-mean-square M difference (after mean removal) is used as the criterion, then the BYC model performs the best for all conditions. It is also apparent that the model-derived profiles may be missing some phenomena in the surface layer such as wave effects. One interesting result is that each model was better at approximating the M profile curvature for stable than for unstable conditions.