关键词: 垂直混合系数, 大洋环流, 敏感性实验, 赤道流系

Abstract: A series of three-dimensional numerical experiments of diagnosing global ocean circulation, based on the MOM4 global model, are used to investigate the sensitivity of global ocean circulation to vertical diffusivity. In the annual mean, vertical diffusivity has a considerable effect on the whole global ocean circulation system, especially in the equatorial Pacific region. Not only is the pattern of potential temperature greatly affected by vertical diffusivity, but also is the velocity field. As a whole, the horizontal and vertical temperature gradient is relative small along with the relative large diffusivity. Correspondingly，the south and north equator currents are rather strong, while the equatorial undercurrent and equatorial counter currents are relative weak. Moreover, each branch of equatorial system varies in their scale at the same time. Such a phenomenon demonstrates that the whole oceanic circulation is rather sensitive to the variation of vertical diffusivity. Furthermore, effects of each parameter in thermal equations within experiments are given. The physical mechanism is also discussed.

Key words: vertical diffusivity, global ocean circulation, sensitivity test, equatorial currents