A COMPARISON OF A HYDRODYNAMIC LENS MODEL TO OBSERVATIONS OF A WARM-CORE RING

Analysis of advanced very high resolution radiometer satellite images has shown long-period fluctuations in ring eccentricity for 82-B. Conc urrent shipboard measurements as well as satellite data also suggest t hat this anticyclonic ring was often paired with one or more cyclonic eddies. Furthermore, satellite image analysis and recent numerical sim ulations suggest strong deformation in the fluid between the anticyclo ne and the cyclone. The purpose here is to investigate a causal relati on between the time dependent environmental deformation and the eccent ricity fluctuations. To this end, we attempt to parameterize the effec ts of the cyclone as environmental forcing on the anticyclone using a nonlinear, non-quasi-geostrophic, hydrodynamic lens model. Our results suggest that the strong deformation in the environmental flow could b e responsible for long-period fluctuations in eccentricity. Other mode l ring features, such as spin (vorticity/2) and rotation rate of 82-B, are discussed and compared to observations. Another significant featu re of the model results is the presence of superinertial frequencies i n the solution fields. Since current mesoscale observation techniques are unable to resolve such high frequencies, it is unknown whether or not this result is realistic.