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An eastward propagation has been observed in the ocean and atmosphere between 30° and 40° in both the northern and southern Pacific oceans. The time period is about 4 years with wavelengths on the order of 15,000 km. The variations appear in the sea surface height (SSH) observed by several altimeter missions, the sea surface temperature (SST), and the atmospheric wind stress curl (WSC). The same type of eastward propagation has been observed throughout the Southern Ocean in the same variables. The relation between the WSC and SSH appears to be a time varying Sverdrup balance that is made possible by the mean eastward drift of the ocean. The propagation speed of the observed anomalies is about 10 cm/s which is the mean eastward velocity in the Southern ocean and at 30° latitude. Thus, through Ekman pumping the WSC continually amplifies SSH anomalies that are moving with the mean drift. SST anomalies are in phase with the SSH anomalies. We are looking to work with numerical climate models to understand the mechanisms by which the SST forms and is maintained and the possible feedback mechanisms from the ocean SST to the atmosphere. The feedback mechanisms are suspected to make this process a coupled ocean/atmosphere wave in which the WSC changes ocean circulation and thus SST, and the SST maintains the WSC.
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