How does ocean ventilation change under global warming?

[摘要] Since the upper ocean takes up much of the heat added to the earth systemby anthropogenic global warming, one would expect that global warming wouldlead to an increase in stratification and a decrease in the ventilation ofthe ocean interior. However, multiple simulations in global coupled climatemodels using an ideal age tracer which is set to zero in the mixed layer andages at 1 yr/yr outside this layer show that the intermediate depths in thelow latitudes, Northwest Atlantic, and parts of the Arctic Oceanbecome younger under global warming. This paper reconciles theseapparently contradictory trends, showing that the decreases result fromchanges in the relative contributions of old deep waters and younger surfacewaters. Implications for the tropical oxygen minimum zones, which playa critical role in global biogeochemical cycling are considered indetail.

[学科分类] 海洋学与技术