Title: Quantifying the sensitivity of nonlinear tides in the Philippine Sea

Authors: Colette Kerry (Department of Oceanography, University of Hawaii at Manoa, Honolulu, Hawaii)
Brian Powell (Department of Oceanography, University of Hawaii at Manoa, Honolulu, Hawaii)

Adjoint sensitivity analysis is used to study the internal tides in the Philippine Sea. This work aims to investigate the predictability of the nonlinear tides and the interactions of the tidal energy and mesoscale oceanic conditions. We use an adjoint model to quantify the sensitivity of the baroclinic energy fluxes to model bathymetry, density and advective structure, as well as a selection of meaningful model parameters. This application demonstrates how the adjoint sensitivity method can simultaneously address the contribution of various background state and model variables to the baroclinic tides.

Complex mesoscale activity as well as significant internal tide energy makes the Philippine Sea a challenging oceanic region to predict. Numerical prediction of mesoscale ocean circulation typically focuses on the mesoscale and tidal forcing is omitted. However in regions with significant baroclinic tidal energy the tidal and mesoscale dynamics are often of comparable magnitude. The adjoint provides a quantitative evaluation of the relative roles of the dynamics and model configuration to the characterization of the baroclinic tides. This information helps us understand the effects of a varying mesoscale field on the internal tides and allows comparison of the importance of background oceanic state and uncertainties in bathymetric representation and model parameters. Our aim is to use this information to better predict the region.

GMAO Head: Michele Rienecker Global Modeling and Assimilation Office NASA Goddard Space Flight Center

Curator: Nikki Privé Last Updated: May 27 2011