140 likes | 243 Views
Internal and external variability of MOC in the Kiel Climate Model (ECHAM5/NEMO) Wonsun Park & Mojib Latif Leibniz Institute of Marine Sciences, Kiel. Internal MOC variability Multidecadal to Multicentennial scales External solar forced variability Idealized experiments.
E N D
Internal and external variability of MOC in the Kiel Climate Model (ECHAM5/NEMO)Wonsun Park & Mojib LatifLeibniz Institute of Marine Sciences, Kiel • Internal MOC variability • Multidecadal to Multicentennial scales • External solar forced variability • Idealized experiments THOR Annual Meeting, Paris, 25-26 November 2009
The Kiel Climate Model (KCM)ECHAM5 (T31L19), NEMO (0.5-2°) Park et al. 2009 J. Clim.
Atlantic MOC(ctrl, 4000yrs) Park and Latif 2008 GRL
MOC mode separation LP 90yrs BP 30-90yrs
SH icevs. MOC Sea ice response to MOC
SH Ice extent vs. MOC LP 90yrs: centennial to multicentennial BP 90-185 LP 185yrs
Freshwater and Sea ice threshold SSS Park et al. in preparation
Climate impacts Surface temperature SLP and wind stress Park et al. in preparation
1000 years 4W/m2 Millennial solar forcing experiments • Solar forcing integration (4200a) : periodic (P=1000a, ±2W/m2) • ECHAM5/MLO simulation (2000a)
Northern Hemisphere temperatureresponse to external solar forcing Jones and Mann (2004) Jones and Mann (2004) reconstruction Latif et al. 2009 Met. Zeit.
Summary • Multidecadal variability is originated in the North Atlantic, whereas multicentennial variability is driven in the Southern Ocean. • Multicentennial Southern Ocean variability is related to the convective activities associated with sea ice capping threshold. • SO multicentennial signal is advected the North Atlantic, and provides stabilization (salinity) effect. • The MOC is strongly phase-locked to the external solar forcing, and provides a strong negative feedback on the NH-SAT.