It is demonstrated that current level models, both with and without assimilation, generate too shallow an overturning in the North Atlantic (just like their predecessors) because they do not reproduce the descent of plumes of cold water from the Greenland and Norwegian Seas. Consequently, the prediction of decadal change from one such model reported by C. Wunsch and P. Heimbach is queried.
Saunders, P. M., Cunningham, S. A., de Cuevas, B. A., & Coward, A. C. (2008). Mean meridional overturning in the North Atlantic 24-26°N: observations and models. A comment on Wunsch and Heimbach (2006). Journal of Physical Oceanography, 38(9), 2104-2107. https://doi.org/10.1175/2008JPO3827.1