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Application of the implicit particle filter to a model of nearshore circulation

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Title Application of the implicit particle filter to a model of nearshore circulation
Names Miller, R. N. (creator)
Ehret, L. L. (creator)
Date Issued 2014-04-14 (iso8601)
Note This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%292169-9291.
Abstract The implicit particle filter is applied to a stochastically forced shallow water model of nearshore
flow, and found to produce reliable state estimates with tens of particles. The state vector of this model consists
of a height anomaly and two horizontal velocity components at each point on a 128 x 98 regular rectangular
grid, making for a state dimension O(10⁴). The particle filter was applied to the model with two
parameter choices representing two distinct dynamical regimes, and performed well in both. Demands on
computing resources were manageable. Simulations with as many as a hundred particles ran overnight on
a modestly configured workstation. In this case of observations defined by a linear function of the state vector,
taken every time step of the numerical model, the implicit particle filter is equivalent to the optimal
importance filter, i.e., at each step any given particle is drawn from the density of the system conditioned
jointly upon observations and the state of that particle at the previous time. Even in this ideal case, the sample
occasionally collapses to a single particle, and resampling is necessary. In those cases, the sample rapidly
reinflates, and the analysis never loses track. In both dynamical regimes, the ensembles of particles deviated
significantly from normality.
Genre Article
Topic data assimilation
Identifier Miller, R. N., and L. L. Ehret (2014), Application of the implicit particle filter to a model of nearshore circulation, Journal of Geophysical Research: Oceans, 119, 2363–2385. doi:10.1002/2013JC009440

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