Yoshida and Nobumasa Komori Graphic Representation of the Gulf Stream Surface Current Speeds in Blue-white (white Is the Fast- Est) and Upward Wind Velocities in Yellow-red (red for Stronger Winds), along with Land-surface

Ocean surface temperatures and wind speeds tend to vary together across ocean basins away from tropical regions. Typically, stronger surface winds are seen over cooler and weaker winds over warmer water, because strong winds cool the ocean surface by evaporation and by stirring up cold subsurface water. But is this always the case? Aside from warm tropical oceans, where moist air ascends high into the atmosphere, are there instances where the ocean significantly impacts the deep atmosphere? Meteorologists have been skeptical, believing that at midlatitudes, the ocean’s effect on the atmosphere is shallow, restricted mainly to the planetary boundary layer. IPRC scientists and their colleagues at other institutions have been seeking to answer this question by looking at ocean fronts, where currents bring about sharp gradients in sea-surface temperature. Some of the first support came in 2002 from air soundings over the spectacular meanders, called Tropical Instability Waves, along the Pacific equatorial front. 1 The soundings revealed that these meanders affect the whole planetary boundary layer. Next, analyses of satellite data showed stronger winds over the warm flank and weaker winds over the cold flank of the Kuroshio as it flows along the southern coast of Japan.2 When the Kuroshio switched between 1998 and 2001 from a straight path that hugs the coast to a meander offshore, the wind fields shifted together with the shift in the Kuroshio path. Now the results published in the March 13 Nature article “Influence of the Gulf Stream on the Troposphere” The Gulf Stream’s Pathway to Impact Climate