Start Submission Become a Reviewer

Reading: Significance of non-rotational wind stress in the seasonal variation of continental torque

Download

A- A+
Alt. Display

Original Research Papers

Significance of non-rotational wind stress in the seasonal variation of continental torque

Authors:

Mayumi K. Yoshioka ,

Ocean Research Institute, University of Tokyo, 1-15-1 Nakano-ku, Minamidai, Tokyo, 164-8639, JP
X close

Hiroshi Niino,

Ocean Research Institute, University of Tokyo, 1-15-1 Nakano-ku, Minamidai, Tokyo, 164-8639, JP
X close

Ryuji Kimura

Ocean Research Institute, University of Tokyo, 1-15-1 Nakano-ku, Minamidai, Tokyo, 164-8639, JP
X close

Abstract

The physical mechanism by which seasonally varying atmospheric wind stress exerted on these a 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 of barotropic oceans. The model has a realistic land–ocean distribution and is driven by a seasonally varying climatic wind stress. A novel way to decompose the wind stress into rotational and non-rotational components is devised. The rotational component drives ocean circulations as classical theories of wind-driven circulations demonstrate. The non-rotational component doesnot produce ocean circulations within the framework of a barotropic shallow-water model, but balances with the pressure gradient force due to surface displacement in the steady state. Based on this decomposition, it is shown that most of the continental torque which plays a major role in producing the seasonal variation of length of day (LOD) is caused by the non-rotational component of the wind stress. Both continental torque due to the wind-driven circulation produced by the rotational component of the wind stress and the bottom frictional torque are of minor importance.

How to Cite: Yoshioka, M.K., Niino, H. and Kimura, R., 2002. Significance of non-rotational wind stress in the seasonal variation of continental torque. Tellus A: Dynamic Meteorology and Oceanography, 54(4), pp.390–405. DOI: http://doi.org/10.3402/tellusa.v54i4.12147
  Published on 01 Jan 2002
 Accepted on 22 Feb 2002            Submitted on 30 Aug 1999

References

  1. Boer , G. J. 1990 . Earth—atmosphere exchanges of angular momentum simulated in a general circulation model and implications for the length of day. J. Geophys. Res . 95 , D5 , 5 – 5531 .  

  2. Bryan , F. 0. 1997 . The axial angular momentum balance of a global ocean general circulation model Dyn . Atmos. Oceans 25 , 191 – 216 .  

  3. Egger , J. and Hoinka , K.-P. 1999 . The equatorial bulge, angular momentum and planetary wave motion . Tellus 51A , 914 – 921 .  

  4. Gill , A. E. 1982 . Atmosphere—ocean dynamics . Academic Press , San Diego , CA , 662 pp .  

  5. Hellerman , S. and Rosenstein , M, 1983 . Normal monthly wind stress over the world ocean with error estimates . J. Phys. Oceanogr . 13 , 1093 – 1104 .  

  6. Ichikawa , H. and Beardsley , R. C. 1993 . Temporal and spatial variability of volume transport of the Kuroshio in the East China Sea . Deep Sea Res. Part I 40 , 583 – 605 .  

  7. Masuda , A. 1991 . Oceanography and mathematics. Sea and Sky 67 , 163 – 175 ( in Japanese ).  

  8. Munk , W. H. and MacDonald , G. F. 1960 . The rotation of the earth . Cambridge University Press , Cam-bridge , 323 pp .  

  9. Oort , A. H. 1985 . Balance conditions in the earth’s climate system , Adv. Geophys . 28A , 75 – 98 .  

  10. Oort , A. H. 1989 . Angular momentum cycle in the atmosphere—ocean—solid earth system . Bull. Am. Meteorol. Soc . 70 , 1231 – 1242 .  

  11. Oort , A. H. and Peixoto , J. P. 1992 . Physics of climate . American Institute of Physics , Washington , DC, 520 pp .  

  12. Pedlosky , J. 1968 . An overlooked aspect of the wind-driven oceanic circulation . J. Fluid. Mech . 32 , 809 – 821 .  

  13. Ponte , R. M. 1990 . Barotropic motions and exchange of angular momentum between the oceans and solid earth, J. Geophys. Res . 95 , C7 , 11369 – 11374 .  

  14. Ponte , R. M. and Gutzler , D. S. 1991 . The Madden—Julian oscillation and the angular momentum balance in a barotropic ocean model. 96, C1, 835 – 842 .  

  15. Ponte , R. M. and Rosen , R. D. 1993 . Determining torques over the ocean and their role in the planetary momentum budget. J. Geophys. Res . 98 , D4 , 4 – 7325 .  

  16. Ponte , R. M. and Rosen , R. D. 1994 . Oceanic angular momentum and torques in a general circulation model . J. Phys. Oceanogr . 24 , 1966 – 1977 .  

  17. Rosen , R. D. , Salstein , D. A. and Wood , T. M. 1990 . Discrepancies in the earth-atmosphere angular momentum budget. J. Geophys. Res . 95 , 95 – 279 .  

  18. Semtner , A. J. Jr and Chervin , R. M. 1992 . Ocean general circulation from a global eddy-resolving model. J. Geophys. Res . 97 , C4 , 4 – 5550 .  

  19. Stommel , H. 1948 . The westward intensification of wind--driven currents , Trans. Am. Geophys. Union 29 , 202 – 206 .  

  20. Veronis , G. 1996 . Effect of a constant, zonal wind on wind-driven ocean circulation . J. Phys. Oceanogr . 26 , 2525 – 2538 .  

  21. Wahr , J. M. and Oort , A. H. 1984 . Friction- and moun-tain-torque estimates from global atmospheric data . J. Atmos. Sci . 41 , 190 – 204 .  

comments powered by Disqus