How does the El Niño‐generated coastal current propagate past the Mendocino escarpment?

During an El Niño, an internal coastal Kelvin wave bore propagates poleward along the west coast of North America, leaving behind a steady anomalous coastal jet. A nonlinear, two‐layer, ƒ plane, shallow‐water model is used to determine the amplitude change of the steady coastal current over an escarpment. As the El Niño‐generated warm coastal current passes the Mendocino escarpment off northern California, its amplitude is marginally enhanced. In contrast, for a cold coastal current, the amplitude will be reduced north of the Mendocino escarpment. When the Kelvin wave bore travels over a depth increase, the amplitude change is predicted to be much larger than over a depth decrease (as in the case of the Mendocino escarpment). This model is also applicable to bottom water flowing equatorward along a western boundary. In this case, much larger amplitude changes are found.