OBSERVATIONS OF LONG ROSSBY WAVES IN THE NORTHERN TROPICAL PACIFIC

Evidence for such waves is found in variations of the depth of the 20°C isotherm in the northern tropical Pacific during 1970-1987. A total of 199 067 bathythermograph profiles have been compiled from the archives of several countries; the data coverage is dense enough that westward propagating events may be observed with a minimum of zonal interpolation. A model of low-frequency quasi-geostrophic pycnocline variability allows the physical processes of Ekman pumping, the radiation of long (nondispersive) Rossby waves due to such pumping in midbasin, and the radiation of long Rossby waves from the observed eastern boundary pycnocline depth fluctuations. -from Author