Ocean Science www.ocean-sci.net 1812-0784 1812-0792 3 3 2007 10.5194/os-3-411-2007 http://www.ocean-sci.net/3/411/2007/ http://www.ocean-sci.net/3/411/2007/os-3-411-2007.html http://www.ocean-sci.net/3/411/2007/os-3-411-2007.pdf 411 416 2007-09-24 Atmospheric forcing of salinity in the overflow of Denmark Strait J. Holfort juergen@holfort.org T. Albrecht Institut für Meereskunde der Universität Hamburg, Hamburg, Germany Deutsche Marine, Zerstörerflottille, Wilhelmshaven, Germany present adress: BSH, Rostock, Germany The temporal evolution of the characteristics of Denmark Strait Overflow Water (DSOW) is reconstructed using hydrographic data and compared with possible atmospheric forcing mechanisms. It is concluded that the main factor influencing the DSOW characteristics at a time scale of one to several years is the difference in mean sea level pressure across Denmark Strait or, in other words, the wind along Denmark Strait. At these time scales upstream changes in the characteristics of the different water masses involved in the formation of DSOW are only of minor importance. The main process responsible for the observed salinity changes in the DSOW is mixing in Denmark Strait. Triggered by the wind, different water masses contribute with changing amounts to the formation of DSOW, leading to the observed changes in the salinity of DSOW. Conkright, M E., Levitus, S., Boyer, T P., O'Brien, T., Stephens, C., Johnson, D., Stathoplos, L., Baranova, O., Antonov, J., Gelfeld, R., Burney, J., Rochester, J., and Forgy, C.: WORLD OCEAN DATABASE 1998, 1998. Dickson, R R., Lazier, J., Meincke, J., Rhines, P., and Swift, J.: Long-term coordinated changes in the convective activity of the North Atlantic, Prog. Oceanogr., 38, 241–295, 1996. Dickson, R R., Medler, K., and Read, J.: Current meter data report for Workpackage 1.4 Denmark Strait Overflow., available at www.ices.dk/ocean/project/veins, 1998. Dickson, R R., Meincke, J., Vassie, I., Jungclaus, J., and \textrmØsterhus, S.: Possible predictability in overflow from the Denmark Strait, Nature, 397, 243–246, 1999. Dickson, R R., Yashayaev, I., Meincke, J., Turrell, B., Dye, S., and Holfort, J.: Rapid freshening of the deep North Atlantic Ocean over the past four decades, Nature, 416, 832–836, 2002. Holfort, J.: FS Poseidon cruise 290 from St.Johns, Canada to Reykjavik, Island, June 6 to June 24, 2002, http://www.ifm.uni-hamburg.de/~wwwro/cruises/Pos290/cruisereport.html, 2002. Hurrel, J W., Kushnir, Y., Ottersen, G., and Visbek, M.: An overview of the North Atlantic Oscillation, in: The North Atlantic Oscillation: climatic significance and environmental impact, edited by: Hurrel, J W., Kushnir, Y., Ottersen, G., and Visbek, M., American Geophysical Union, 1–36, 2003. Rudels, B., E F., Meincke, J., Budeus, G., and Eriksson, P.: The Eastgreenland current and its contribution to the Denmark Strait Overflow., J. Mar. Sci., 59, 1133–1154, 2002. Saunders, P.: The dense northern Overflows, in: Ocean circulation and climate, observing and modelling the global ocean., edited by: Siedler, G., Church, J., and Gould, J., Academic Press, p 712, 2001. Schott, F., Koltermann, K P., Stramma, L., Sy, A., Zahn, R., and Zenk, W.: North Atlantic, cruise No 39, 18 April–14 September 1997, available at www.marum.de/Meteor-Berichte.html, 1998. Schott, F., Meincke, J., Meinecke, G., Neuer, S., and Zenk, W.: North Atlantic 1999, Cruise No 45, 18 May–4 November 1999, available at www.marum.de/Meteor-Berichte.html, 2000. Schott, F., Fischer, J., Holfort, J., and Zenk, W.: North Atlantic, Cruise No 50, 7 May–12 August 2001, available at www.marum.de/Meteor-Berichte.html, 2002. WOCE Data Products Committee: WOCE Global Data, Version 3.0, WOCE Report, 180/02, 2002.