Data-assimilation by delay-coordinate nudging

Abstract

A new nudging method for data assimilation, delay-coordinate nudging, is presented. Delay-coordinate nudging makes explicit use of present and past observations in the formulation of the forcing driving the model evolution at each time-step. Numerical experiments with a low order chaotic system show that the new method systematically outperforms standard nudging in different model and observational scenarios, also when using an un-optimized formulation of the delay-nudging coefficients. A connection between the optimal delay and the dominant Lyapunov exponent of the dynamics is found based on heuristic arguments and is confirmed by the numerical results, providing a guideline for the practical implementation of the algorithm. Delay-coordinate nudging preserves the easiness of implementation, the intuitive functioning and the reduced computational cost of the standard nudging, making it a potential alternative especially in the field of seasonal-to-decadal predictions with large Earth system models that limit the use of more sophisticated data assimilation procedures.

minor changes, 10 pages, to appear in Q. J. R. Meteorol. Soc

References in corpus (4)

• Continuous Data Assimilation for the 2D Bénard Convection through Velocity Measurements Alone
• Structure of characteristic Lyapunov vectors in spatiotemporal chaos
• Quantifying uncertainty in state and parameter estimation
• Synchronizing spatio-temporal chaos with imperfect models: a stochastic surface growth picture

Cited by in corpus (5)

• Synchronization to big-data: nudging the Navier-Stokes equations for data assimilation of turbulent flows
• Long short-term memory embedded nudging schemes for nonlinear data assimilation of geophysical flows
• Synchronizing subgrid scale models of turbulence to data
• A probabilistic scheme for joint parameter estimation and state prediction in complex dynamical systems
• Reconstructing Rayleigh-Bénard flows out of temperature-only measurements using nudging