The top layer pushes on the layerbelow, and again the Coriolis effectcomes into play: The second layer movesnot in the same direction as the top one,but slightly to the right, and slightly slower. This process passes down throughthe water column, each layer beingpushed by the sheet above and pushingthe one below. The direction that the water moves changes down the water col-umn in a spiral (Fig. 15.29), called the
Ekman spiral
after the Swedish oceanog-rapher who discovered it.