Contents

152 6 Rotational EffectsFig. 6.20 Illustration for the description of the geostrophic adjustment process6.12.2 How Does It Work?Initially, lateral pressure gradients associated with the slope of the density interfacecreates bottom f ow directed radially inward (Fig. 6.21). Consequently, the sea levelwill start to rise in the centre of this patch owing to the resultant fl w convergencein the bottom layer. Pressure-gradients owing to a tilted sea level, on the other hand,creates surface fl w directed radially outward. On time scales of the inertial periodand beyond, the Coriolis force comes into play and deflect these f ows. The initialradial spreading turns into circular geostrophic motion. Water-column squeezingproduces a geostrophic eddy of cyclonic vorticity in the low-density surface patch.Water-column stretching produces a clockwise rotating eddy in the ocean underneath.Fig. 6.21 Illustration of the geostrophic adjustment process in a 2-layer ocean and resultantgeostrophic eddies for the northern hemisphere