Event Type:

Applied Mathematics and Computation Seminar

Date/Time:

Friday, February 22, 2013 - 04:00

Location:

GLK 104

Event Link:

Guest Speaker:

Institution:

CEOAS

Abstract:

The impact of assimilation of wave-averaged flow velocities on the bathymetric

correction is studied in tests with synthetic (model-generated) data using

tangent-linear and adjoint components of a one-way coupled nearshore wave-circulation

model. The tangent linear model is build using line-by-line differentiation of the

nonlinear code. The adjoint model is also constructed line-by-line as a transpose of

the tangent linear code. Weakly and strongly nonlinear regimes are considered,

featuring energetic unsteady along-beach flows responding to time-independent

wave-averaged forcing due to breaking waves. It is found that assimilation of

time-averaged velocities on a regular grid (mimicking an array of remotely-sensed data)

provides sensible corrections to bathymetry. The adjoint-based representer formalism

allows separating contributions of the circulation and wave adjoint model components to

the bathymetric correction. The array mode analysis reveals that there are very few

modes that can be effectively corrected, given the assumed data error level. Additional

tests show the utility of different observational arrays in providing the bathymetric

correction.