Variability of Pacific subtropical cells in the 50-year ECCO assimilation

Abstract

The Pacific Subtropical Cell (STC) circulation is being analyzed from transport time series across 9°S and 9°N, obtained from the German ECCO (GECCO) assimilation results for the period 1952-2002. In this estimate, the interior Pacific STC convergence shows significantly less decadal slowdown from the 1960's to the 1990's (∼5Sv), than in previous estimates based on hydrographic sections. In the GECCO results, about half of this STC convergence decrease is compensated by an increase in the equatorward transport of the western boundary currents. Overall, the STC varies primarily on interannual time scale, with relatively short time lags between STC convergence and transport variations of the Equatorial Undercurrent at 140°W. Copyright 2007 by the American Geophysical Union.