The spatial variability of vertical velocity in an Iceland basin eddy dipole

► Diagnosis of mesoscale spatial variability of vertical velocity in an eddy dipole. ► Strong signature in central jet due to large PV anomaly of mode water eddy (MWE). ► PV gradient inhibits lateral transport in MWE, damping vertical velocity signature. ► Shows that diagnosing mesoscale vertical velocity must be tackled as a 3D problem. ► Full examination of potential sources of error of vertical velocity diagnosis.