One hundred-Earth-year mean streamfunction of oceanic meridional overturning circulation (MOC, left column) and atmospheric meridional circulation (right column) in the experiments with the default diffusivity (a− b), and 10 times(c−d) and 100 times (e−f) the defaultdiffusivity. The positive values represent the clockwise cells, and the negative values represent the anti-clockwise cells. The color bar in (e) is different from that in (a) and (c).