Intensifying precipitation over the Southern Ocean challenges reanalysis-based climate estimates – Insights from Macquarie Island's 45-year record

Kong, Zhaoyang; Prata, Andrew T.; May, Peter T.; Purich, Ariaan; Huang, Yi; Siems, Steven T.

doi:10.5194/wcd-6-1643-2025

Articles | Volume 6, issue 4

https://doi.org/10.5194/wcd-6-1643-2025

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

https://doi.org/10.5194/wcd-6-1643-2025

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

Articles | Volume 6, issue 4

Research article

|

03 Dec 2025

Research article |

| 03 Dec 2025

Intensifying precipitation over the Southern Ocean challenges reanalysis-based climate estimates – Insights from Macquarie Island's 45-year record

Zhaoyang Kong, Andrew T. Prata, Peter T. May, Ariaan Purich, Yi Huang, and Steven T. Siems

Data sets

NASA Shuttle Radar Topography Mission Global 1 arc second NASA JPL https://doi.org/10.5067/MEASURES/SRTM/SRTMGL1.003

ERA5 hourly data on pressure levels from 1940 to present Copernicus Climate Change Service (C3S) https://doi.org/10.24381/cds.bd0915c6

ERA5 hourly data on single levels from 1940 to present Copernicus Climate Change Service (C3S) https://doi.org/10.24381/cds.adbb2d47

Short summary

To investigate why ERA5 (European Centre for Medium-Range Weather Forecasts Reanalysis v5) does not accurately capture the observed increase in annual precipitation at Macquarie Island during 1979 to 2023, we classify daily synoptic systems using k-means clustering. Find that the increase in mean intensity across all systems is the main contributor to the observed annual precipitation trend and the resulting discrepancy, rather than changes in the frequency. And this increase may also have a substantial impact on the freshwater fluxes over the Southern Ocean.