Impact of the extratropical Pacific on equatorial variability

Abstract

An ocean general circulation model (OGCM) is used with a data assimilation routine to explore how the higher latitudes in the Pacific affect equatorial variability. The assimilation of observed temperature data in the extratropical regions generates decadal variability on the equator, indicating that the subsurface thermal structure of the tropics may be modulated by low-frequency variability in the higher latitudes. While preliminary analyses show that midlatitude temperature anomalies can be advected to the subtropics along isopycnal surfaces, it is also demonstrated that a wave mechanism may be one of the dominant physical processes by which information is carried from the higher latitudes to the equatorial region. Copyright 1997 by the American Geophysical Union.