Effects of Spectral Nudging on Oceanic States in a Coarse-Resolution Model |
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| Authors: | Zeliang Wang Guoqi Han Frederic Dupont |
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| Institution: | 1. Ocean and Ecosystem Sciences Division, Bedford Institute of Oceanography, Fisheries and Oceans Canada, Dartmouth, Nova Scotia, Canada;2. Northwest Atlantic Fisheries Centre, Fisheries and Oceans Canada, St. John's, Newfoundland and Labrador, Canada;3. Meteorological Research Division, Environment Canada, Dorval, Quebec, Canada |
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| Abstract: | A 1-degree global model is used to investigate the skill of spectral nudging at coarse resolution by performing two numerical experiments, one with spectral nudging and the other without. In the spectral nudging experiment, the model temperature and salinity are nudged to an observed climatological monthly-mean field. The study compares the model mean state, as well as the interannual and decadal variability of oceanic quantities with observations, (e.g., sea surface height (SSH) and sea surface temperature (SST)). Spectral nudging is found to be effective in constraining model drift from the observed mean state of temperature and salinity in the global ocean, which has been reported in previous studies. The present study further shows that spectral nudging significantly improves the model skill of topostrophy (a measure of currents flowing along the topography) in water depth below 2000?m with no clear improvement elsewhere. Despite its known ability to damp oceanic variability at various time scales, spectral nudging can still represent the interannual and decadal variability of SSH and SST well, to a degree comparable to the other experiment. |
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| Keywords: | spectral nudging coarse-resolution model global ocean interannual and decadal variability |
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