[1] Since 1992, upper ocean ADCP current data between New York and Bermuda have been gathered from the container ship Oleander to identify long-term changes in the shelf, slope, Gulf Stream and Sargasso Sea. Temperature and surface salinity data have been been collected along this route since 1978 by NOAA/NMFRC. The first ten years of ADCP data from which the effects of warm ring have been removed are used to describe processes within the shelfbreak frontal sub-region. The Eulerian mean velocity structure shows an along-isobath shelfbreak jet with maximum speeds of O(0.15 m s À1 ) offshore of which is a $30 km wide relatively quiescent region. There is also an offshore slope current 40 to 50 km wide extending vertically to 300 m, with similar velocities as those found in the shelfbreak jet. The mean shelfbreak jet transport is 0.4 Sv while the slope current adds another 2.5 Sv. Maximum shelfbreak transport occurs in the fall and winter while the slope current reaches its maximum during the spring. In stream coordinates, the shelfbreak jet has maximum speeds of 0.35 m s À1, a width of $30 km and a vertical decay scale of $50 m. The maximum Rossby number within the jet, defined by jdU/dyj max /f, is about 0.2. Significant interannual fluctuations occur in upper ocean temperature, salinity and currents, some of which appear related to changes in the NAO index. Seasonal changes in the slope current appear to be related to seasonal changes in the wind stress curl over the slope sea.

Abstract.The continually leak from the current into the Slope Sea. These observations point to a thermohaline rather than winddriven mechanism for governing the path of the Gulf Stream after it leaves the coast.

Monthly monitoring of surface and water column temperature, and surface salinity across the Middle Atlantic Bight and Gulf of Maine has been conducted since 1976 and 1978, respectively. Presented are the temporal and spatial patterns of these features in 1996 and their comparisons to mean patterns for the base period, 1978-92. Middle Atlantic Bight surface and bottom temperatures and surface salinities during 1996 were the lowest since the beginning of the base period. Annual, 1996, averaged surface temperature over the entire transect was 1.9°C lower than the base period mean; similarly averaged bottom temperature was-0.8°C cooler; and like averaged surface salinities was 1.17 PSU below that of the base period. In the more detailed time-space sense, Middle Atlantic Bight temperatures were significantly lower than average 1) over the mid-to outer shelf from February through April, 2) over the shelf and slope during July and August, 3) over the mid-shelf in October, and 4) well offshore in November. Negative departures of surface salinity occurred over the shelf throughout 1996 and after July over the entire transect reaching the Gulf Stream. Bottom temperatures were significantly below average on the mid-shelf during January, expanding inshore by April. Negative departures occurred over the outer shelf area during the early summer, and continued through most of the remainder of 1996. In the Gulf of Maine, annual, 1996 averaged surface temperature along the entire transect was 1.1°C below the baseline, and similarly averaged bottom temperature was 0.2°C above the mean. In the time-space sense, Gulf of Maine surface temperatures were significantly below the baseline from January through March in Massachusetts Bay, extending eastward to Crowell Basin in March. At this same time surface temperatures were as much as 4°C above average on the Scotian Shelf. From early July through September colder than average temperatures existed across the entire transect. Bottom temperatures were cooler than normal during January in Massachusetts Bay and in June through December on the Scotian Shelf. Starting in January over the central Gulf ledges warmer than average bottom temperatures were observed. Significant positive anomalies reached the Scotian Shelf in February, Massachusetts Bay by March and continued in the mid-Gulf until July.