EGU22-4671, updated on 21 Apr 2023
EGU General Assembly 2022
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

A novel method for objective identification of weather-relevant 3-D potential vorticity anomalies

Christoph Fischer1,2, Andreas H. Fink2, Elmar Schömer1, Roderick van der Linden2, Michael Maier-Gerber2, Marc Rautenhaus3, Shun Yiu Chung2, Marvin Kriening2, and Michael Riemer4
Christoph Fischer et al.
  • 1Institute of Computer Science, Johannes-Gutenberg University, Mainz, Germany
  • 2Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Karlsruhe, Germany
  • 3Regional Computing Centre, Visual Data Analysis Group, University of Hamburg, Hamburg, Germany
  • 4Institute for Atmospheric Physics, Johannes-Gutenberg University, Mainz, Germany

Potential vorticity (PV) analysis plays a central role in studying atmospheric dynamics and in particular in studying the life cycle of weather systems. The three-dimensional (3-D) structure and temporal evolution of the associated PV anomalies, however, are not yet fully understood. An automated technique to objectively identify 3-D PV anomalies can help to shed light on 3-D atmospheric dynamics in specific case studies, as well as facilitate statistical evaluations within climatological studies. Such a technique to identify PV anomalies fully in 3-D, however, does not yet exist.

This study presents a novel algorithm for the objective identification of PV anomalies. The algorithm is inspired by morphological image processing techniques and can be applied to both two-dimensional (2-D) and 3-D fields on vertically isentropic levels.

The method maps input data to a horizontally stereographic projection and relies on an efficient computation of horizontal distances within the projected field. Candidates for PV anomaly features are filtered according to heuristic criteria, and feature description vectors are obtained for further analysis. The generated feature descriptions are well suited for subsequent case studies of 3-D atmospheric dynamics, or for generation of climatologies of feature characteristics.

We evaluate our approach by comparison with an existing 2-D technique, and demonstrate the full 3-D perspective by means of meteorological case studies comprising tropical cyclogenesis and a subtropical extreme rainfall event. These case studies demonstrate the complexity and variations in the 3-D structure of the detected PV anomalies. Such anomalies are often insufficiently captured by a 2-D method. We discuss further advantages of using a 3-D approach, including elimination of temporal inconsistencies in the detected features due to 3-D structural variation, and elimination of the need to manually select a specific isentropic level on which the anomalies are assumed to be best captured.

How to cite: Fischer, C., Fink, A. H., Schömer, E., van der Linden, R., Maier-Gerber, M., Rautenhaus, M., Chung, S. Y., Kriening, M., and Riemer, M.: A novel method for objective identification of weather-relevant 3-D potential vorticity anomalies, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4671,, 2022.


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