FY 1988

Remote westerly wind forcing of the eastern equatorial Pacific; some model results

Harrison, D.E., and B.S. Giese

Geophys. Res. Lett., 15(8), 804–807, doi: 10.1029/GL015i008p00804 (1988)

An ocean circulation model is used to examine modes of eastern Pacific ocean response to an episode of surface westerly winds in the western Pacific. This episode resembles the May 1986 tropical cyclone pair event. The ocean changes resulting from this episode are isolated by subtracting the circulation that would otherwise have been present. First and second mode baroclinic Kelvin pulses have comparable surface eastward flow, and cause local warming when the surface temperature gradient is negative. The Kelvin pulses also introduce modulations of the eastern Pacific instability waves, which initially increase the mid-ocean warming and then damp it out. South American coastal warming is substantial, but occurs many months after the wind event because it result primarily from the second baroclinic mode response. Recent analyses of the ocean response to the cyclone event have concentrated on the first mode Kelvin pulse response; this work indicates that only a very incomplete view of the response is possible from this perspective.