Variability of the Gulf Stream position and transport between 1992 and 1999: a re‐analysis based on a data assimilation experiment
Abstract:A multivariate dataset resulting from the assimilation of sea surface height and sea surface temperature data in an ocean circulation model of the North Atlantic, is used to study the Gulf Stream position variability from October 1992 to October 1999. The analysis takes place between 75° W and 50° W and focuses on two regions, west and east of 65° W. By calculating zonal averages of the latitudinal position, a regular annual cycle of north–south oscillations of the Gulf Stream axis is identified in the eastern region, whereas inter-annual variations dominate in the western region. An empirical orthogonal function (EOF) analysis of space–time position anomalies reveals that, even though the annual cycle dominates over the whole domain, the variability has a spatial consistency within each individual region. The assimilation dataset is further used to analyse the variability of the Gulf Stream transport towards the east. Compared to the latitudinal position analysis, the characterization of the transport variability is more complex. Semi-annual fluctuations can be evidenced in both the regions; however, no significant correlation was found between the fluctuations of position and transport.
Document Type: Research Article
Publication date: January 20, 2006