Gulf of California response to Hurricane Juliette

The HYbrid Coordinate Ocean Model (HYCOM) has been configured for the Gulf of California (GOC) at 1/12° and 1/25° horizontal grid resolution and has been nested inside a basin-scale 1/12° Pacific version of HYCOM. The nested GOC models are used to study the upper-ocean GOC response to Hurricane Juliette. The model results indicate that Juliette’s winds forced strong poleward coastal baroclinic currents (meridional velocity >60 cm/s) along the southwestern coast of the GOC. That reversed the well-observed mean equatorward currents along the southeastern coast of the Baja California Peninsula. These Juliette-induced currents forced a transport variation of >0.2 Sv along the entrance of the GOC. In addition, Juliette’s winds increased the mixed layer depth (from ∼5 m to ∼40 m) and induced strong upwelling (vertical velocity >30 m/day) along the southeastern coast of the Baja California Peninsula. The model simulated upwelling is corroborated by model independent analysis of SeaWiFS chlorophyll-a satellite measurements. During its early stage Juliette generated a coastally trapped wave (CTW) along mainland Mexico. After its generation the CTW propagated poleward along the coasts of the mainland and GOC, where it reached the shelf break between the 28°N and 29°N and it reversed the direction and propagated equatorward along the western coast of the GOC. Next, the CTW propagated to the southwestern coast of the GOC, where it partially modulated the intensity of the Juliette-generated coastal upwelling.