“Beyond Weather Regimes”: Descriptors Monitoring Atmospheric Centers of Action. A case study for Aotearoa New Zealand

AbstractThis paper introduces a set of descriptors applied to weather regimes, that allow for a detailed monitoring of the location and intensity of their atmospheric centers of action (e.g. troughs and ridges) and the gradients between them, when applicable. Descriptors are designed to document the effect of climate variability and change in modulating the character of daily weather regimes, rather than merely their occurrence statistics.As a case study, the methodology is applied to Aotearoa New Zealand (ANZ), using ERA5 ensemble reanalysis data for the period 1979-2019. Here, we analyze teleconnections between the regimes and their descriptors, and large-scale climate variability. Result…