CoAuthors

Baringer Molly (NOAA/AOML, US); Goni Gustavo (NOAA/AOML, US)

The location and strength of the Gulf Stream determined from altimeter measurements from 80W to 50W since late 1992 are analyzed, and compared with these from XBT and current meter measurements along a high-density XBT transect and Oleander section. During the altimeter period, the Gulf Stream experiences a strong southward shift, which is dominated by the region east of 65W after the Gulf Stream passes the New England Seamount. This southward shift is accompanied by a weakening of the Gulf Stream, also dominated by the region east of 65W. This explains why the measurements from the oleander section, crossing the Gulf Stream around 70.5W, did not capture the weakening of the Gulf Stream. On interannual time scales, the Gulf Stream experiences strong intensification during two periods, 1995-1996 and 2003-2004. Interestingly, the 1995-1996 peak in the Gulf Stream strength mainly comes from the eastern region, east of 65W. Whereas, the 2003-2004 peak is dominated by the region to the west of 65W. Gulf Stream changes in different regions may have different impact on air-sea interaction processes. In this study, the corresponding changes in the vertical thermal structure in the upper ocean, changes in the air-sea heat fluxes and in the subtropical mode water processes are investigated.