An anonymous reader shares a Nature article: The North Atlantic Ocean is a major driver of the global currents that regulate Earth's climate, mix the oceans and sequester carbon from the atmosphere -- but researchers haven't been able to get a good look at its inner workings until now. The first results from an array of sensors strung across this region reveal that things are much more complicated than scientists previously believed. Researchers with the Overturning in the Subpolar North Atlantic Program (OSNAP) presented their findings this week at an ocean science meeting in Portland, Oregon. With nearly two years of data from late 2014 to 2016, the team found that the strength of the Atlantic Meridional Overturning Circulation -- which pumps warm surface water north and returns colder water at depth -- varies with the winds and the seasons, transporting an average of roughly 15.3 million cubic metres of water per second. The measurements are similar in magnitude to those from another array called RAPID, which has been operating between Florida and the Canary Islands since 2004. But scientists say they were surprised by how much the currents measured by the OSNAP array varied over the course of two years.