Water mass distribution in Fram Strait and over the Yermak Plateau in summer 1997

The water mass distribution in northern Fram Strait and over the Yermak Pla teau in summer 1997 is described using CTD data from two cruises in the are a. The West Spitsbergen Current was found to split, one part recirculated t owards the west, while the other part, on entering the Arctic Ocean separat ed into two branches. The main inflow of Atlantic Water followed the Svalba rd continental slope eastward, while a second, narrower, branch stayed west and north of the Yermak Plateau. The water column above the southeastern f lank of the Yermak Plateau was distinctly colder and less saline than the t wo inflow branches. Immediately west of the outer inflow branch comparative ly high temperatures in the Atlantic Layer suggested that a part of the ext raordinarily warm Atlantic Water, observed in the boundary current in the E urasian Basin in the early 1990s, was now returning, within the Eurasian Ba sin, toward Fram Strait. The upper layer west of the Yermak Plateau was col d, deep and comparably saline, similar to what has recently been observed i n the interior Eurasian Basin. Closer to the Greenland continental slope th e salinity of the upper layer became much lower, and the temperature maximu m of the Atlantic Layer was occasionally below 0.5 degrees C, indicating wa ter masses mainly derived from the Canadian Basin. This implies that the wa rm pulse of Atlantic Water had not yet made a complete circuit around the A rctic Ocean. The Atlantic Water of the West Spitsbergen Current recirculati ng within the strait did not extend as far towards Greenland as in the 1980 s, leaving a broader passage for waters from the Atlantic and intermediate layers, exiting the Arctic Ocean. A possible interpretation is that the cir culation pattern alternates between a strong recirculation of the West Spit sbergen Current in the strait, and a larger exchange of Atlantic Water betw een the Nordic Seas and the inner parts of the Arctic Ocean.