Competition of NAO regime changes and increasing greenhouse gases and aerosols with respect to Arctic climate projections

PDF: http://data.dhkim.info/monograph/CD/WWT24847VHC2V334.pdf

Article  

  Climate Dynamics
Publisher: Springer-Verlag Heidelberg
ISSN: 0930-7575 (Paper) 1432-0894 (Online)
DOI: 10.1007/s00382-003-0344-2
Issue: Volume 21, Numbers 5-6

Date:  November 2003
Pages: 447 - 458  
Competition of NAO regime changes and increasing greenhouse gases and aerosols with respect to Arctic climate projections
W. Dorn1 , K. Dethloff1, A. Rinke1 and E. Roeckner2

(1)  Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg A43, 14473 Potsdam, Germany,  
(2)  Max Planck Institute for Meteorology, Bundesstraße 55, 20146 Hamburg, Germany,  


W. Dorn
Email: wdorn@awi-potsdam.de

Received: 4 July 2002  Accepted: 14 May 2003  Published online: 29 August 2003

Abstract   Regional magnitudes and patterns of Arctic winter climate changes in consequence of regime changes of the North Atlantic Oscillation (NAO) are analyzed using a regional atmospheric climate model. The regional model has been driven with data of positive and negative NAO phases from a control simulation as well as from a time-dependent greenhouse gas and aerosol scenario simulation. Both global model simulations include a quite realistic interannual variability of the NAO with pronounced decadal regime changes and no or rather weak long-term NAO trends. The results indicate that the effects of NAO regime changes on Arctic winter temperatures and precipitation are regionally significant over most of northwestern Eurasia and parts of Greenland. In this regard, mean winter temperature variations of up to 6 K may occur over northern Europe. Precipitation and synoptic variability are also regionally modified by NAO regime changes, but not as significantly as temperatures. However, the climate changes associated with the NAO are in some regions clearly stronger than those attributed to enhanced greenhouse gases and aerosols, indicating that projected global changes of the atmospheric composition and internal circulation changes are competing with each other in their importance for the Arctic climate evolution in the near future. The knowledge of the future NAO trend on decadal and longer time scales appears to be vitally important in terms of a regional assessment of climate scenarios for the Arctic.