Optimal modes of atmospheric and oceanic motions under linear approximation have been applied to the investigations of predictability, sensitivity and stability. For example, linear singular vector has been applied not only in the estimation of prediction uncertainties, which is one of the central problems in predictability of weather and climate, but also in ensemble forecast and adaptive observation; it has also been used to identify the unstable modes for large-scale meteorology and oceanography, and even for a coupled system. In particular, linear singular vector has been used to study the singular modes for mesoscale meteorology.
In recent years, there have been considerable efforts to generalize linear optimal modes into nonlinear category, such as nonlinear singular vectors, nonlinear Lyapunov vector, and conditional nonlinear optimal perturbations. And remarkable applications have also been found in predictability, sensitivity and stability studies by demonstrating the importance of nonlinear processes in the problems studied. Identification of nonlinear optimal modes has also been made for large scale meteorology, mesoscale meteorology, oceanography, and coupled system.
This session invites the contributions from scientists who are working on the theoretical and numerical studies of linear and nonlinear optimal modes. The session also welcomes those who explore applications of optimal modes in quantifying the predictability of different weather and climate phenomena from thunderstorms, torrential rains, tropical cyclones and typhoons to ENSO and climate change with time scales ranging from a few hours to centuries. Besides, works related to the applications of optimal modes to the sensitivity and stability studies in geophysical fluid dynamics are also welcome