T. Vukicevic et Rm. Errico, LINEARIZATION AND ADJOINT OF PARAMETERIZED MOIST DIABATIC PROCESSES, Tellus. Series A, Dynamic meteorology and oceanography, 45A(5), 1993, pp. 493-510
The problems related to the development and applications of an adjoint
model for a nonlinear model that has discontinuities in the governing
equations are discussed in this study. We ''amine the hypothesis that
a useful tangent linear model and its associated adjoint model can be
developed for such a nonlinear model by using the reference state to
determine the regimes associated with the discontinuities. Our nonline
ar and linear experiments for the Pennsylvania State University/Nation
al Center for Atmospheric Research regional forecast model show that l
inearization of moist diabatic parameterizations is feasible using thi
s method, but significant errors may be expected in the regions where
transitions are frequent and associated with large tendency changes du
e to the model's moist diabatic parameterizations. We conclude that th
e tangent linear model and its associated adjoint model would be more
accurate for a nonlinear model that has more well-behaved regime trans
itions. We suggest that nonlinear tests similar to the analysis shown
in this study be performed prior to developing these linear models. If
these tests show high nonlinearity due to regime transitions as a con
sequence of model deficiencies, we recommend first improving the nonli
near model before performing the linearization.