Submesoscale cascade in a data-assimilative coupled ocean-atmosphere model of the subtropical northwest Pacific

The ARCTERX stated goal of advancing our understanding of the nature of the ocean submesoscale cascade in the northwest Pacific will be addressed in this project using a high-resolution data-assimilative regional coupled model. The proposed work and analysis is motivated by two current lines of scientific inquiry: (1) an inverse cascade paradigm for the ARCTERX region where the development ofstrong submesoscale during winter strengthens mesoscale eddies leading to a kinetic energy increase during May-June each year, and (2) the recent realization that coupled ocean-atmosphere processes can potentially modulate the submesoscale and mesoscale production and the energy cascade. Based on this insight, this projects overall objective is to evaluate to what extent high model resolution and the coupling of the ocean with the atmosphere modify the submesoscale variability and its energy cascade .Specific questions motivating the science objective are: (1) Can high-resolution models represent the critical processes of the energy cascade correctly? Moreover, (2) are coupled ocean-atmosphere processes relevant in reproducing the energy cascade accurately? Data assimilation of observations provided by autonomous instrument platforms during ARCTERX, complemented by remotely sensed data, will provide a unique opportunity to constrain the model dynamics and explore these questions in the northwest Pacific region. The proposed approach leverages on very recent enhancements to the Regional Ocean Modeling System (ROMS) code that allows for (i) the relatively easy coupling of ROMS with atmospheric models and (2) the inclusion of coupled ocean-atmosphere feedbacks in the assimilation of ocean observations. In addition, the variational tools of the modeling system will be used to provide guidance to the ARCTERX team in developing strategies to deploy observational assets.