www.elsevier.com/locate/csr Nitrogen and carbon cycling in the North Sea and exchange with the North Atlantic—A model study. Part I. Nitrogen budget and fluxes

• Main Author: Johannes Pätsch
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2008
• Subjects: North Atlantic; North Atlantic oscillation
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.177.7566; http://ca.umces.edu/%7Eboesch/se-pubs/Patsch%20Kuhn%202008.pdf

The three-dimensional biogeochemical model ECOHAM was applied to the Northwest European Shelf (47141 0 –63153 0 N, 1515 0 W–13155 0 E) for the years 1993–1996. Nitrogen budgets were calculated for the years 1995 and 1996 for the inner shelf region, the North Sea (511,725 km 2). Simulated temperatures as well as nitrate, oxygen, and chlorophyll concentrations are compared with observations. The mid-1990s were chosen because they exhibit a shift from a very high North Atlantic Oscillation Index (NAOI) in winter, 1994/1995, to an extremely low one in winter, 1995/1996, with consequences for the North Sea system: During the first-half of 1996, the observed mean sea surface temperature (SST) was about 1 1C lower than in 1995; in the southern part of the North Sea the difference was even larger. These observations could be reproduced by the model. Due to a different wind regime, the normally prevailing anti-clockwise circulation, also found in winter 1995, was replaced by more complicated patterns in winter 1996. Decreased precipitation over the drainage area of the continental rivers led to a reduction in the total riverine nitrogen loads to the North Sea from 76 Gmol N yr 1 in