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Published January 20, 2026 | Version v7
Dataset Open

The System for Classification of Low-Pressure Systems (SyCLoPS) Dataset (Based on ERA5)

  • 1. ROR icon University of California, Davis

Description

This is the ERA5 System for Classification of Low-Pressure Systems (SyCLoPS) dataset version 7. SyCLoPS is an LPS classifier built upon the TempesteExtremes (TE) software (GitHub link). Details of SyCLoPS algorithms are described in the paper titled The System for Classification of Low-Pressure Systems (SyCLoPS): An All-in-One Objective Framework for Large-scale Data sets published on J. Geophys. Res. Atm.: [https://doi.org/10.1029/2024JD041287]. Please cite this paper if you use this dataset.

Important: The most up-to-date SyCLoPS codes are now kept on GitHub: [https://github.com/yepkids/SyCLoPS

SyCLoPS user manual: [https://climate.ucdavis.edu/syclops.php]
*See Chapter 3 of the manual for instructions on how to load and use the output classified catalog*

Updates in this version:

  1. The classified and input LPS datasets have been extended from 1970-2024 to 1940-2024. The classified catalog contains the final classification labels for the LPS nodes and tracks. The input catalog contains the parameters used for classification.
  2. We also provide an equivalent dataset with a 6-hourly tracking frequency (the default is 3 hours). The longer interval alters the beginning and ending phases (when the intensity of the LPS nodes is weak) of some tracks and is expected to produce longer tracks in general. The stitching parameters used in this experiment are described in the comments of the main SyCLoPS program.
  3. The IKE column is removed from this version of the dataset. 
  4. The relative vorticity field is now computed directly in the TE software instead of from the ERA5 data.
  5. We add an "adjusted label" column to compensate for short-term fluctuations/instabilities in the classification labels. Please see the supporting information S4 in our new paper for details (preprint link). It is recommended that this column be used for the final classification.

The following files can be obtained from version 4:

  1. The labeled size blobs of each year: "size_blobs_1979_2022.tar.gz"
  2. The labeled precipitation blobs of each year: "preci_blobs_1979_2022.tar.gz"

Other SyCLoPS-related data products:

  1. SyCLoPS HighresMIP LPS catalogs: Link
  2. SyCLoPS HighresMIP TC-only catalogs: Link

Please contact Yushan Han (yshhan@ucdavis.edu) if you have questions about the SyCLoPS framework. Please contact Paul Ullrich (paullrich@ucdavis.edu) if you have any questions about the TE software.

See below for a table of atmospheric variables required for SyCLoPS and a flowchart of the classification process. See the SyCLoPS manual for more details.

 

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Additional details

References

  • Ullrich, P. A., & Zarzycki, C. M. (2017). Tempestextremes: A framework for scale-insensitive pointwise feature tracking on unstructured grids. Geoscientific Model 1154 Development , 10 (3), 1069–1090.
  • Ullrich, P. A., Zarzycki, C. M., McClenny, E. E., Pinheiro, M. C., Stansfield, A. M., & Reed, K. A. (2021). Tempestextremes v2.1: A community framework for feature detection, tracking and analysis in large datasets. Geoscientific model development discussions, 2021 , 1–37.
  • Han, Y., & Ullrich, P. A. (2025). The system for classification of low-pressure systems (SyCLoPS): An all-in-one objective framework for large-scale data sets. Journal of Geophysical Research: Atmospheres, 130, e2024JD041287.