Group seminar on 11. June, 14:15
Local Identification of Equatorial Waves
João B. Cruz
Equatorial waves (EWs) are of special interest in the field of tropical meteorology as they are associated to a variety of tropical atmospheric phenomena, such as cloud and precipitation variability, precipitation extremes, tropical convection, tropical cyclogenesis and the quasi-bienial oscillation. To our knowledge, there have not been previous efforts toward developing projection techniques that identify EWs in local data. Here we present a local identification technique for Kelvin and mixed Rossby-gravity (MRG) waves, the EWs that fill the gap between the Rossby and inertia-gravity regimes. The method allows for the identification of Kelvin and MRG waves at specific longitudes using the meridional structures of the solutions to the free Laplace tidal equations, known as Hough vector functions. The main advantages of the method lie in its local character and the possibility to be applied with zonal varying background states. The method also reveals the difficulty of distinguishing between the meridional structures of the westward MRG and eastward MRG (also known as EIG1) waves.