Figure F1. Circulation and upwelling from a coupled ocean-atmosphere general circulation model (from Huber, 2002). Streamlines represent circulation at a depth of ~100 m. Whereas there are strong similarities to modern ocean circulation, there are important differences. Most notably, there is a southern Pacific subpolar gyre to complement the Alaska Gyre in the North Pacific and there is one southern subtropical gyre that sweeps through both the South Pacific and Indian Oceans. The Alaska Gyre is also shifted northward by 10° when compared to its modern position. Red = regions of vigorous upwelling; green to blue = regions of weak upwelling; white = areas of mean downwelling.