期刊名称：Tellus A: Dynamic Meteorology and Oceanography
电子版ISSN：1600-0870
出版年度：2002
卷号：54
期号：4
页码：390-405
DOI：10.3402/tellusa.v54i4.12147
摘要：The physical mechanism by which seasonally varying atmospheric wind stress exerted on thesea surface is communicated to the solid earth as oceanic pressure torque (continental torque)and bottom frictional torque is investigated with a linear shallow-water numerical model ofbarotropic oceans. The model has a realistic land–ocean distribution and is driven by a seasonallyvarying climatic wind stress. A novel way to decompose the wind stress into rotational andnon-rotational components is devised. The rotational component drives ocean circulations asclassical theories of wind-driven circulations demonstrate. The non-rotational component doesnot produce ocean circulations within the framework of a barotropic shallow-water model, butbalances with the pressure gradient force due to surface displacement in the steady state. Basedon this decomposition, it is shown that most of the continental torque which plays a majorrole in producing the seasonal variation of length of day (LOD) is caused by the non-rotationalcomponent of the wind stress. Both continental torque due to the wind-driven circulationproduced by the rotational component of the wind stress and the bottom frictional torque areof minor importance.
