STABLE: An open-source atmospheric blocking and subtropical ridge detection system

Abstract

The SubTropical Atmospheric ridge and BLocking Event (STABLE) algorithm is an open-source Python-based tool for the tracking of high-pressure systems, distinguishing between subtropical ridges and types of atmospheric blockings. The output includes 2-D daily spatial structures allowing the spatio-temporal tracking of high-pressure events, as well as compiled statistics of their characteristics. Building upon state-of-the-art geopotential gradient methodology, STABLE introduces customizable changes to refine the structure identification and classification, improve usability, and extend the algorithm's adaptability. Key inclusions are a zonally varying subtropical boundary, refined criteria for polar blocking, and an advanced classification scheme for hybrid blocking events. Validation with reanalysis data for the 1991–2020 period demonstrates STABLE's ability to capture high-pressure events and improved accuracy while preserving replicability of earlier results. STABLE offers a user-friendly framework for customizable studies focusing on atmospheric dynamics and climate variability, historical trends and future projections or region-specific impact assessments.