Role of cabbeling in water densification in the Greenland Basin

[摘要] The effects of cabbeling mixing on water mass modification in the GreenlandSea were explored by hydrographic observations across the Greenland Basin insummer 2006. The neutral surface was chosen as a reference frame, and thestrength of cabbeling mixing was quantified by the dianeutral velocitymagnitude. Active cabbeling spots were detected with the criterion of thevelocity magnitude >1 m/day, and four active cabbeling areas wereidentified; the west of Bear Island (SB), the Arctic Frontal Zone (AFZ), thecentral Greenland Sea (CG) and the western Greenland Sea (WG). The mostvigorous cabbeling mixing was found at SB, where warm North Atlantic Water(NAW) mixed with cold water from the Barents Sea, inducing a maximumvelocity of 7.5 m/day and a maximum density gain of 4.7×10⁻³ kg/m³.At AFZ and CG, the mixing took place between NAW, modified NAWand Arctic Intermediate Water (AIW), and the density gain at these frontswere 1.5×10⁻³ kg/m³ (AFZ) and 1.3×10⁻³ kg/m³ (CG).In the western Greenland Sea, the active cabbeling spots were widelyseparated and mixing appeared to be rather weak, with a maximum velocity of2.5 m/day. The mixing source waters at WG were modified NAW, AIW and evendenser water, and the density gain in this area was 0.4×10⁻³ kg/m³.The deepest mixing produced water whose density is equivalent tothat of the dense water of the basin, indicating that cabbeling in thewestern Greenland Sea contributed directly to basin-scale waterdensification. The water mass modification rate was the highest at AFZ(about 8.0 Sv), suggesting that cabbeling may play an important role inwater transformation in the Greenland Basin.

[学科分类] 海洋学与技术