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

The S ub T ropical A tmospheric ridge and BL ocking E vent (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. • STABLE is an open-source code to track atmospheric blockings and subtropical ridges. • It has user-changeable characteristics to better fit the necessitates of the study. • A longitude-asymmetrical approach is introduced to identify subtropical ridges. • Polar blocks are more carefully considered, with a revised polar gradient. • Introduced alternatives produce consistent surface impacts with previous methods.