Nonlinear finite-time Lyapunov exponent and predictability

In this Letter, we introduce a definition of the nonlinear finite-time Lyapunov exponent (FTLE), which is a nonlinear generalization to the existing local or finite-time Lyapunov exponents. With the nonlinear FTLE and its derivatives, the limit of dynamic predictability in large classes of chaotic systems can be efficiently and quantitatively determined.