GLOBAL MEASURES OF LOCAL CONVECTIVE INSTABILITIES

We examine the linear stability of the Ginzburg-Landau operator with s patially varying coefficients, which mimics strongly nonparallel open flows such as wakes, jets, and boundary layers. The streamwise non-nor mality of the global eigenmodes explains the observed large transient growths, classically interpreted in terms of local convective instabil ity. The use of pseudospectra provides an exact measure of spatial amp lification and aids in the determination of when entrance noise domina tes the open-flow dynamics.