Decadal variability in high northern latitudes as simulated by an intermediate-complexity climate model

• Published in: Annals of Glaciology
• Main Authors: Goosse, Hugues, Selten, FM, Haarsma, RJ, Opsteegh, JD, International-Glaciological-Society Symposium on Sea Ice and Its Interactions with the Ocean, Atmosphere and Biosphere
• Other Authors: UCL - SC/PHYS - Département de physique, UCL - SST/ELI/ELIC - Earth & Climate
• Format: Conference Object
• Language: English
• Published: Int Glaciological Soc 2001
• Subjects: albedo; Annals of Glaciology; Arctic; Fram Strait; Sea ice
• Online Access: http://hdl.handle.net/2078.1/61829; https://doi.org/10.3189/172756401781818482

A 2500 year integration has been performed with a global coupled atmospheric-sea-ice-ocean model of intermediate complexity with the main objective of studying the climate variability in polar regions on decadal time-scales and longer. The atmospheric component is the ECBILT model, a spectral T21 three-level quasi-geostrophic model that includes a representation of horizontal and vertical beat transfers as well as of the hydrological cycle. ECBILT is coupled to the CLIO model, which consists of a primitive-equation free-surface ocean general circulation model and a dynamic-thermodynamic sea-ice model. Comparison of model results with observations shows that the ECBILT CLIO model is able to reproduce reasonably well the climate of the high northern latitudes. The dominant mode of coupled variability between the atmospheric circulation and sea-ice cover in the simulation consists of an annular mode for geopotential height at 800 hPa and of a dipole between the Barents and Labrador Seas for the sea-ice concentration which are similar to observed patterns of variability. In addition, the simulation displays strong decadal variability in the sea-ice volume, with a significant peak at about 18 years. Positive volume anomalies are caused by (1) a decrease in ice export through Fram Strait associated with more anticyclonic winds at high latitudes, (2) modifications in the freezing/melting rates in the Arctic due to lower air temperature and higher surface albedo, and (3) a weaker heat flux at the ice base in the Barents and Kara Seas caused by a lower inflow, of warm Atlantic water. Opposite anomalies occur during the volume-decrease phase of the oscillation.