SW Origin of North Pacific’s Wide Warm Surface Current

Abstract

There is a long and wide continuous trough of deep mixed layers connecting the tropical western North Pacific Ocean with the offshore waters of the coast of California. Relatively warm water that is nearly uniform vertically fills the trough, which is concluded here to be a northeastward flow joining the wide warm surface current at mid-latitudes off California documented earlier. Evi-dence for the trough comes from a North Pacific atlas based on very many indi-vidual mixed layer depth data points, taken over a 27-year period, compiled (av-eraged) in monthly mean charts with contours of constant mixed layer depth dis-played. BTs (bathythermographs) were used to record temperature versus depth continuously from which the mixed layer depths were determined. Centerline curves, connecting the deepest mixed layer depths, which approximate the mid-dle of the troughs, are constructed from the atlas and are presented for all twelve months. In going from west to east, these curves bend counterclockwise, gradu-ally most of the way then more markedly near California. The curves for the summer months come closer to California than any of the other ones do, suggest-ing that the warm current itself is nearest to California in summer. Confirmation of the prediction awaits future efforts.