On the predictability of flow-regime properties on interannual to Interdecadal timescales

摘要

Atmospheric flow regimes are usually defined as large-scale circulation patterns associated with statistical equilibria in phase space, in which the dynamical tendencies of the large-scale flow are balanced by tendencies due to non-linear interactions of high-frequency transients. The existence of states with such properties can be verifies in a rigorous way in numerical simulations with simplified numerical model (as in the pioneering study of Reinhold and Pierrehumbert (1982), or in the experiments by Vautard and Legras (1998)). On the other hand, the existence of flow regimes in the real atmosphere has been strongly debated. The detection of regimes in the observational record of upper-air field is indeed a complex task, which has been approached by a number of research groups with a variety of sophisticated statistical methods (see Section 3).