Reasons for a fresher northern North Atlantic in the late 20th century

Observational analyses suggest that the northern North Atlantic is fresher in the late 20th century in comparison to the 1950–60s. Here we examine possible contributors to these observed changes by analyzing a four‐member ensemble of 20th century simulations from a coupled climate model. Results show that a weaker meridional freshwater divergence related to a weaker thermohaline circulation in the North Atlantic is the primary cause for the freshening in the northern North Atlantic in the model. The increased P‐E tends to enforce it, but the reduced sea ice flux into this region tends to weaken it.