Implementation of a Balance Operator in NCOM

Abstract

The balance operator and its adjoint for the Navy Coastal Ocean Model (NCOM) have been coded. The operator is implemented in two modes: (a) with and (b) without the integral continuity constraint. Testing the code in an Adriatic Sea configuration has shown that although the a-mode option is several times more computationally expensive, it provides half the ageostrophic motions excited by perturbations with a typical horizontal scale of the internal Rossby radius of deformation. For a state vector of 1.5M degrees of freedom, the total CPU time required by the code is negligible compared to the CPU time required by 1 hour of NCOM integration (i.e., 15 and 80 times less for the a- and b-mode options, respectively). The code could be used in the design of the background error covariance operators in both variational and ensemble applications of data assimilation.

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Document Details

Document Type
Technical Report
Publication Date
Apr 07, 2016
Accession Number
ADA635596

Entities

People

  • Max I. Yaremchuk
  • Paul J. Martin

Organizations

  • United States Naval Research Laboratory

Tags

Communities of Interest

  • Materials and Manufacturing Processes

DTIC Thesaurus Topics

  • Adriatic Sea
  • Algorithms
  • Assimilation
  • Boundary Layer
  • Coefficients
  • Continuity
  • Covariance
  • Diffusion
  • Equations
  • Grids
  • High Resolution
  • Integrals
  • Layers
  • Military Research
  • Oceans
  • Pressure Gradients
  • Three Dimensional

Fields of Study

  • Physics

Readers

  • Finite Element Method (FEM) for solving Partial Differential Equations (PDEs)
  • Ocean-Atmosphere Mesoscale Modeling, Data Assimilation, and Flux Boundary Layers
  • Wave Propagation and Nonlinear Chaotic Dynamics.