Impact of intra-seasonal coastal Kelvin waves on SST in the Canary upwelling system: composite analysis in Spring

<p>The impact of intra-seasonal coastally trapped waves on SST in the Canary upwelling system is studied in satellite estimates of sea surface height, wind, and temperature, using a composite analysis of propagating upwelling and downwelling events. We focus on Spring, the season of strongest SST variability at this frequency. The results obtained show that the average wave reaches an amplitude at sea level of +/- 2 cm and is associated with an SST signal of +/-0.4 °C in the vicinity of the upwelling front, located off Senegal. Strikingly, this composite wave is reinforced by a constructive meridional wind anomaly when it reaches the upwelling front, the wind signal is likely as important as the wave in terms of SST impacts. We discuss the possible cause of this synchronicity in terms of basin-scale atmosphere and ocean waves.<br>Keywords:<br>- Impact<br>- Coastal Kelvin waves<br>- Intra-seasonal<br>- Boundary upwelling systems<br>- Composite analysis of spring<br>- Tropical Atlantic</p>

Resonant excitation of coastal Kelvin waves in the two-layer rotating shallow water model

Resonant excitation of coastal Kelvin waves by free inertia–gravity waves impinging on the coast is studied in the framework of the simplest baroclinic model: two-layer rotating shallow water with an idealized straight coast. It is shown that, with respect to the previous results obtained with the one-layer model, new resonances leading to a possible excitation of Kelvin waves appear. The most interesting ones, described in the paper, are resonances of a baroclinic inertia–gravity wave with either another wave of this kind, or with a coastal current, leading to generation of a barotropic Kelvin wave. A forced Hopf equation results in any case for the evolution of the Kelvin wave amplitude.