Identification of Stream Dispersion Coefficients by Adjoint Sensitivity Method

Abstract

A numerical technique is presented for identification of spatially distributed dispersion coefficients for 2D mass transport in vertically mixed rivers and estuaries. The method is based on a nonlinear optimization procedure that minimizes the squared error between observed and computed concentration values. Gradient information is efficiently computed by the adjoint sensitivity method, so that the same effort is required regardless of the number of parameters involved. The method's limitations are presented, and the conditions of identifiability of the dispersion coefficients are investigated. Numerical tests on complex bathymetric configurations are presented to provide guidelines for the optimum location of monitoring stations. A large-scale application is presented corresponding to the upper Potomac estuary.