Spiral inertial waves emitted from geophysical vortices

By simulating geophysical vortices with strong background rotation and high Reynolds number, we discover for the rst time the emergence of inertial waves that are emitted in a spiral manner from the vortices; we refer to this kind of waves as spiral inertial waves (SIWs). Using parameter-sweep experiments, we nd that SIWs amplitude, wavelength and eigenfrequency are sensitive to Rossby numbers, and that SIWs is well-organized only at small Rossby numbers (0.01<Ro<1). By analogy with Lighthill-Ford radiation, we propose an indicator for the emission of inertial waves; this indicator may be adopted into general circulation models to include the parameterization of inertial waves. Additionally, we demonstrate that SIWs can organize material into horizontal spiral stripes, and that can facilitate the vertical exchange of material. Further, based on the pattern similarity between the spiral stripes in numerical experiments and those in eld observations, e.g. spiral sea eddies and spiral hurricane rainbands, we suggest that the SIW is one of the mechanisms for the development of these spiral geophysical features.