Ekman transport and upwelling during Younger Dryas estimated from wind stress from GENESIS climate model experiments with variable North Atlantic heat convergence

Reconstructed climatic changes during the Younger Dryas interval are simila r to, but somewhat larger and more widespread than, those expected based on the direct atmospheric effects of reduced North Atlantic oceanic heat tran sport. The paleoclimatic data show that North Atlantic cooling during the Y ounger Dryas was accompanied by stronger winds in many regions, suggesting that enhanced wind-driven ocean upwelling may have served as a positive fee dback on the cooling. We test this hypothesis using the GENESIS atmospheric general circulation model, and find that Younger Dryas-age specified reduc tion in North Atlantic oceanic heat transport increases tropical Ekman dive rgence by approximate to 10% in regions and at times of prominent upwelling , sufficient to affect tropical temperatures.