Ocean current hemisphere due to imposed wind stresses. In these wind-driven currents, the Ekman spiral effect results in the currents flowing at an angle to the driving winds. In addition, the areas of surface ocean currents move somewhat with the seasons; this is most notable in equatorial currents. Deep ocean basins generally have a non-symmetric surface current, in that the eastern equatorward-flowing branch is broad and diffuse whereas the western poleward flowing branch is very narrow. These western boundary currents (of which the Gulf Stream is an example) are a consequence of the rotation of the Earth. Deep ocean currents are driven
North Atlantic Gyre warms. This is due to a weakening of the westerly winds, resulting in reduced wind stress and heat exchange, providing a greater period of time for the gyre water temperatures to rise. Collections of aerosols, marine particles, and ocean water in the North Atlantic Gyre from 1990-1992 have led to measurements in lead isotope ratios. These measurements exceed those associated with atmospheric pollution carried from Europe by the trade winds, implying that the majority of lead contamination in the gyre in the early 1990s was primarily caused by American emissions. The surface layers of the Sargasso Sea were used to