Control simulation experiment with Lorenz's butterfly attractor

[摘要] In numerical weather prediction (NWP), sensitivity to initial conditions brings chaotic behaviors and an intrinsic limit topredictability, but it also implies an effective control in which a smallcontrol signal grows rapidly to make a substantial difference. The ObservingSystems Simulation Experiment (OSSE) is a well-known approach to studypredictability, where “nature” is synthesized by an independent NWP model run. In this study, we extend the OSSE and design the controlsimulation experiment (CSE), where we apply a small signal to control “nature”. Idealized experiments with the Lorenz-63 three-variable system show that we can control “nature” to stay in a chosen regime withoutshifting to the other, i.e., in a chosen wing of Lorenz's butterfly attractor, by adding small perturbations to “nature”. Using longer-lead-time forecasts, we achieve more effective control with aperturbation size of less than only 3 % of the observation error. We anticipate our idealized CSE to be a starting point for a realistic CSE using the real-world NWP systems, toward possible future applications to reduceweather disaster risks. The CSE may be applied to other chaotic systemsbeyond NWP.

[学科分类] 自动化工程