Evaluating the 20th Century Reanalysis Version 3 with synoptic typing and an East Antarctic ice core accumulation record

Nilssen, Max T.; Udy, Danielle G.; Vance, Tessa R.

doi:https://doi.org/10.5194/cp-21-897-2025

Articles | Volume 21, issue 5

https://doi.org/10.5194/cp-21-897-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/cp-21-897-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 21, issue 5

Research article

|

16 May 2025

Research article |

| 16 May 2025

Evaluating the 20th Century Reanalysis Version 3 with synoptic typing and an East Antarctic ice core accumulation record

Max T. Nilssen, Danielle G. Udy, and Tessa R. Vance

Data sets

Evaluating the Twentieth Century Reanalysis Version 3 with synoptic typing and an East Antarctic ice core accumulation record: code and data Max Nilssen https://doi.org/10.5281/zenodo.14635919

Towards a more reliable historical reanalysis: Improvements for version 3 of the Twentieth Century Reanalysis system (https://psl.noaa.gov/data/gridded/data.20thC_ReanV3.html) Laura C. Slivinski et al. https://doi.org/10.1002/qj.3598

The Law Dome ice core 2000 year dataset collection Mark Curran et al. https://doi.org/10.26179/5zm0-v192

The International Surface Pressure Databank version 2 (https://psl.noaa.gov/data/20CRv3_ISPD_obscounts/) Thomas A. Cram et al. https://doi.org/10.1002/gdj3.25

The International Surface Pressure Databank version 4 G. P. Compo et al. https://doi.org/10.5065/9EYR-TY90

Model code and software

Self organizing map Rcode for Udy et al 2021 Danielle Udy https://doi.org/10.5281/zenodo.12730195

Short summary

Reanalyses can be used to study past weather and climate, but their reliability is uncertain in data-sparse regions, such as the southern Indian Ocean. We used weather typing and an ice core record from East Antarctica to show that the 20th Century Reanalysis project can better represent the weather conditions that lead to snowfall variability at the ice core site when key weather observations from the Southern Ocean (e.g. Macquarie Island) commence around the mid-20th century.