In the case of Typhoon Fanapi, formation seemed to be aided by the superposition of oceanic warm eddy features on the disturbance track. Following subsequent intensification, cold wake' formation seemed to be modulated by cold eddy features near the track, which limited RI. The cold wake of Typhoon Fanapi persisted as a subsurface cold anomaly for more than three weeks, preconditioning the ocean for Typhoon Chaba, whose rapidly formed cold wake lead to rapid weakening as it crossed Fanapi's track.
In Super-Typhoon Megi, which formed and travelled over deep tropical ocean water, aircraft dropsondes were deployed in and near the eyewall following RI. Pairs of dropsondes were deployed that illustrated remarkably different boundary layer wind profiles. In all, four pairs of sondes were deployed in each quadrant of the eyewall. Each of these pairs exhibited a high shear and low shear companion within a very short distance of each other. The surface layer spacing of these sondes appears to be about the same scale as apparent micro-scale vortices seen along the inner eyewall in airborne radar and SAR imagery. In addition, these sondes show a shallow surface layer with constant wind speed and direction that violates the log-law profile typical of well mixed layers. Speculation as to the causes of these features will be offered.