in Thermohaline Forcing in Northern Latitudes: A Model Study

• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1994
• Subjects: Greenland; Denmark Strait; Greenland-Scotland Ridge; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.456.8625; http://www.vliz.be/imisdocs/publications/147177.pdf

To avoid an explicit simulation of the overflows across the Greenland-Scotland ridge, many models of the large-scale ocean circulation seek to include the net effect of the inflowing dense water masses by restoring temperature and salinity near the ridge to observed conditions. In this paper the authors examine the effect of different datasets for the northern restoring condition in two versions, eddy resolving and non-eddy resolving, of the model of the North and equatorial Atlantic that has been developed in recent years as a Community Modeling Effort for WOCE. It is shown that the use of smoothed climatological fields o f temperature and salinity south of the Denmark Strait leads to strong deficiencies in the simulation of the deep flow field in the basin. A switch to actual hydrographic data from the Denmark Strait ignites a rapid dynamic response throughout the North Atlantic, affecting the transport and vertical structure of the deep western boundary current and, by virtue of the JEBAR effect, the transport of the horizontal gyres. Meridional overturning and northward heat transport, too weak in the cases with climatological boundary conditions, increase to more realistic levels in the subtropical North Atlantic. The initial response to switches in the high-latitude thermohaline forcing is mediated by fast waves along the western boundary, leading to changes in the deep western boundary current in low latitudes after about two