Quantifying the Effect of the Lunar Nodal Tide on North Pacific Climate Variability


This project will investigate the link between changes in tides due to the 18.6-year lunar nodal cycle (LNC) and decadal climate variability in the North Pacific. A globally consistent parameterization of tidal mixing, that has already been tested in a climate model of intermediate complexity and shown to lead to climatically significant sea surface temperature anomalies, will be implemented in a comprehensive global climate model. This parameterization includes a novel scheme of sub-grid scale bathymetry and separately considers four tidal constituents (M2, S2, K1 and O1) and their temporal variations due to the LNC. The model will be used to simulate the effects of LNC oscillations of tidal mixing on diapycnal diffusivities, temperatures, oceanic and atmospheric circulation, and modes of decadal variability in the North Pacific. Model results will be analyzed and carefully compared to existing observations. Satellite altimeter data, now available over one full LNC, will be analyzed with the goal to improve tidal energy dissipation estimates, tidal mixing parameterizations, and the understanding of mechanisms of barotropic energy loss.

Funded by

the National Science Foundation's Physical Oceanography Program


  • Schmittner, A., Green, J. A. M., and Wilmes, S.-B. (2015)
    Glacial Ocean Overturning Intensified by Tidal Mixing in a Global Circulation Model
    Geophysical Research Letters, 42(10), 4014-4022, doi: 10.1002/2015GL063561.
  • Schmittner, A., and Egbert, G. D. (2014)
    An improved parameterization of tidal mixing for ocean models
    Geoscientific Model Development, 7, 211-224, doi:10.5194/gmd-7-211-2014.
  • Presentations

  • Danabasoglu, G., Ullman, D., Schmittner, A., Norton, N. J., and Müller (2016)
    Internal Wave Driven Mixing: Determining the Effect of the Lunar Nodal Cycle on Tidal Mixing and North Pacific Climate Variability (Poster)
    CLIVAR Open Science Conference, Sep. 21, Qingdao, China

  • Ullman, D., Schmittner, A., Danabasoglu, G., Norton, N. J., and Müller (2016)
    Determining the effect of the lunar nodal cycle on tidal mixing and North Pacific climate variability (Poster)
    Ocean Sciences Meeting, Feb. 21-26, New Orleans, LA

  • Danabasoglu, G., Norton, N., Schmittner, A., and Ullman, D. (2015)
    Tidal Mixing Parameterizations in POP2
    Climate Process Team on Diapycnal Mixing, Final Workshop, Oct. 27-29, La Jolla, CA

  • Schmittner, A., Gebbie, J. and Huber, M. (2015)
    Tides and Turbulence in Past Oceans
    Climate Process Team on Diapycnal Mixing, Final Workshop, Oct. 27-29, La Jolla, CA

  • Schmittner, A. Egbert, G. Ullman, D. Danabasoglu, G., and Norton, N. (2014)
    An Improved Parameterization of Tidal Mixing for POP2 (Poster)
    19th Annual CESM Workshop, Jun. 16-19, Breckenridge, CO

  • Schmittner, A., Egbert, G., and Green, M. (2014)
    Modeling Tidal Mixing, Past, Present, and Future (Oral)
    Ocean Sciences Meeting, Feb. 27, Honolulu Presentation (pdf) Abstract

  • People