VARIABILITY OF SUBPOLAR NORTH ATLANTIC CIRCULATION FROM ALTIMETRY

altimeter data show that subpolar north atlantic sea surface height has underwent large variations during the last two decades. similarly the associated geostrophic velocity field exhibits large fluctutations in the strength of the subpolar gyre circulation such that the gyre was extremely strong in the early 1990's but may have been weaker in the late 1990s than in the late 1970s and 1980s. numerical model experiments suggests that the 1990s had also large coincident changes in the meridional overturning in the north atlantic ocean