what is this dark area near the east coast of Japan?? something went bezerk in the pacific ocean???

snapshot archive here [link to www7320.nrlssc.navy.mil]

goes back to 2004

For instance, september 2004 looked like this : [link to www7320.nrlssc.navy.mil]

2003 November


[link to www7320.nrlssc.navy.mil]

Nothing out of the ordinary.

It is just warm water top layer over there.

[link to www7320.nrlssc.navy.mil]

here is the a vid for that area for the last year. Looks like it's normal, at least for the recent timeframe. Who knows prior to Fukushima.

Not really a weather wonder here tbh, but I googled it.. this may explain:

[link to www.seos-project.eu]

Kuroshio current : 'Warm water with an average yearly sea surface temperature exceeding 29 c exists in the tropical equatorial region. This body of water is called the warm pool and extends over an area 30 times larger than Japan. It is located in the equatorial zone between New Guinnea and the international date line. This warm pool is created by trade winds blowing from east to west. '

'The central regions of the subtropical ocean gyres are broad expanses of generally calm air associated with the subtropical high-pressure systems. The light winds means calm seas, with little mixing by waves. The strong sun heats the water to considerable depth'