Advances in Atmospheric Sciences

, Volume 29, Issue 3, pp 529–543

The tropical intraseasonal oscillation in SAMIL coupled and uncoupled general circulation models

  • Jing Yang (杨 静)
  • Qing Bao (包 庆)
  • Xiaocong Wang (王晓聪)
  • Tianjun Zhou (周天军)
Article

DOI: 10.1007/s00376-011-1087-3

Cite this article as:
Yang, J., Bao, Q., Wang, X. et al. Adv. Atmos. Sci. (2012) 29: 529. doi:10.1007/s00376-011-1087-3

Abstract

Simulations of tropical intraseasonal oscillation (TISO) in SAMIL, the Spectral Atmospheric Model from the Institute of Atmospheric Physics (IAP) State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) coupled and uncoupled general circulation models were comprehensively evaluated in this study. Compared to the uncoupled model, the atmosphere-ocean coupled model improved the TISO simulation in the following aspects: (1) the spectral intensity for the 30–80-day peak eastward periods was more realistic; (2) the eastward propagation signals over western Pacific were stronger; and (3) the variance distribution and stronger signals of Kelvin waves and mixed Rossby gravity waves were more realistic. Better performance in the coupled run was assumed to be associated with a better mean state and a more realistic relationship between precipitation and SST. In both the coupled and uncoupled runs, the unrealistic simulation of the eastward propagation over the equatorial Indian Ocean might have been associated with the biases of the precipitation mean state over the Indian Ocean, and the unrealistic split of maximum TISO precipitation variance over the Pacific might have corresponded to the exaggeration of the double Intertropical Convergence Zone (ITCZ) structure in precipitation mean state. However, whether a better mean state leads to better TISO activity remains questionable. Notably, the northward propagation over the Indian Ocean during summer was not improved in the mean lead-lag correlation analysis, but case studies have shown some strong cases to yield remarkably realistic northward propagation in coupled runs.

Key words

tropical intraseasonal oscillation atmosphere-ocean interaction mean state northward propagation simulation 

Copyright information

© Chinese National Committee for International Association of Meteorology and Atmospheric Sciences, Institute of Atmospheric Physics, Science Press and Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  • Jing Yang (杨 静)
    • 1
  • Qing Bao (包 庆)
    • 2
  • Xiaocong Wang (王晓聪)
    • 2
  • Tianjun Zhou (周天军)
    • 2
  1. 1.State Key Laboratory of Earth Surface Processes and Resource EcologyBeijing Normal UniversityBeijingChina
  2. 2.State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina

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