Dynamic sea level changes following changes in the thermohaline circulation

Abstract

Using the coupled climate model CLIMBER-3a, we investigate changes in sea\nsurface elevation due to a weakening of the thermohaline circulation (THC). In\naddition to a global sea level rise due to a warming of the deep sea, this\nleads to a regional dynamic sea level change which follows\nquasi-instantaneously any change in the ocean circulation. We show that the\nmagnitude of this dynamic effect can locally reach up to ~1m, depending on the\ninitial THC strength. In some regions the rate of change can be up to 20-25\nmm/yr. The emerging patterns are discussed with respect to the oceanic\ncirculation changes. Most prominent is a south-north gradient reflecting the\nchanges in geostrophic surface currents. Our results suggest that an analysis\nof observed sea level change patterns could be useful for monitoring the THC\nstrength.\n