title: Logarithmic bred vectors in spatiotemporal chaos: structure and growth.
abstract: Bred vectors are a type of finite perturbation used in prediction studies of atmospheric models that exhibit spatially extended chaos. We study the structure, spatial correlations, and the growth rates of logarithmic bred vectors (which are constructed by using a given norm). We find that, after a suitable transformation, logarithmic bred vectors are roughly piecewise copies of the leading Lyapunov vector. This fact allows us to deduce a scaling law for the bred vector growth rate as a function of its amplitude. In addition, we relate growth rates with the spectrum of Lyapunov exponents corresponding to the most expanding directions. We illustrate our results with simulations of the Lorenz 1996 model.
authors.affiliation: Instituto de Física de Cantabria (IFCA), CSIC-Universidad de Cantabria, E-39005 Santander, Spain. sarah.hallerberg@physik.tu-chemnitz.de
authors.forename: Sarah
authors.initials: S
authors.lastname: Hallerberg
authors.forename: Diego
authors.initials: D
authors.lastname: Pazó
authors.forename: Juan M
authors.initials: JM
authors.lastname: López
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Rodríguez