Abstract
This work provides an updated set of 12 dominant geopotential height
fields - or ‘regimes’ - over Aotearoa New Zealand. These regimes were
initially produced by Kidson (2000) and have provided the basis for many
other subsequent studies. These maps provide a guide to the prevailing
weather due to the broad equivalence of 1000hPa geopotential height and
mean-sea-level pressure. The results presented here are broadly in
agreement with previous work but with some important differences. The
most notable of these being the need to average two blocking regimes
together to provide good agreement between this work and Kidson (2000).
These differences are attributed to the software used, improvements to
the underlying dataset itself and to the ‘mixing’ of statistically
indistinguishable empirical orthogonal functions - EOFs - in different
linear combinations. All data and code used in this work is publicly
accessible and it is hoped that this will provide a catalyst for open
discussions on this topic, particularly with relation to future
perturbations to these regimes under climate change.