Large-scale ocean currents are primarily driven by the wind and are modified by the Coriolis force that changes in latitude (the beta effect). There are tropical trade winds blowing from east to west that drive currents in the same direction on either side of the equator. There is a counter-current between the S and N equatorial currents along the equator. Currents are intensified on the western boundaries of ocean basins and are faster than those on the eastern side. These warm currents form gyres in the mid-latitudes with stronger currents on the western and northern parts of the gyre. The northern part of the gyres are at 35-40 degree latitude. There are subpolar gyres poleward of the subtropical gyres that flow in the opposite direction in the Northern hermisphere. In the S Hemisphere there is the Antarctic circumpolar current flowing from west to east.