A numerical study of the wintertime double-warm-tongue structure in the Huanghai（Yellow） Sea

Satellite remote sensing observations show that during winter, sea surface temperature （SST） presents the structure of double warm tongues in the Huanghai Sea trough： the western and the eastern warm tongues. Numerical experiments based on POM are carried out to study the forming mechanism of this thermal structure and its relation to the Huanghai Sea Warm Current （HSWC）. The control experiment reproduces this phenomenon quite well, and comparing experiments investigate the effect of wind and tide. It is found that the western warm tongue is mainly caused by the HSWC, which can be strengthened by wintertime southward wind. The eastern warm tongue develops under the influence of an anti-clockwise circulation which is induced by the temperature front of the Huanghai Sea Cold Water Mass （HSCWM） in summer and autumn. In the eastern portion of this circulation, the northward current carries warm water to the north, forming the eastern warm tongue, which remains till winter.