Skip to main content
Log in

Dynamical downscaling using CGCM ensemble average: an application to seasonal prediction for summer precipitation over South Korea

  • Research
  • Published:
Theoretical and Applied Climatology Aims and scope Submit manuscript

Abstract

This study investigates how to properly downscale the coupled general circulation model (CGCM) ensemble prediction dynamically more efficiently than conventional method. Specifically, the ensemble seasonal prediction skill of dynamically downscaled precipitation over South Korea is evaluated by comparing two experiments. The first experiment (EXP1) involves conventional ensemble forecasts. Five ensemble members (EMs) are downscaled dynamically with initial and lateral boundary conditions obtained from the outputs of five CGCM EMs. The results of each EM are averaged for ensemble prediction utilizing a simple composite method. The second experiment (EXP2) is the same as EXP1, but the initial and lateral boundary conditions are obtained by arithmetically averaging the outputs of the five CGCM EMs. Therefore, five integrations are carried out for the EXP1, but only one integration is performed for the EXP2. The results show that EXP2 simulates closer to the observed precipitation than EXP1. This improvement is attributed to the strongly simulated upper zonal wind that can influence the vertically integrated moisture flux convergence. EXP2 shows comparable or better performance in simulating the interannual variability of summer precipitation than EXP1. Unlike conventional methods, such as EXP1, EXP2 provides a prediction in a single integration, and the prediction is similar to or even better than the one obtained conventionally. Hence, EXP2 can be a powerful means to drastically reduce the prediction time by reducing the number of ensemble integration to just one.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11

Similar content being viewed by others

Data availability

The CMAP precipitation reanalysis data were provided by the NOAA/OAR/ESRL Physical Sciences Laboratory (https://psl.noaa.gov/data/gridded/data.cmap.html). The ERA5 precipitation reanalysis data were obtained from the Copernicus Climate Change Service (https://doi.org/10.24381/cds.bd0915c6). The weather station precipitation data over South Korea were provided by the Korean Meteorological Administration (https://data.kma.go.kr/data/grnd/selectAsosRltmList.do?pgmNo=36).

References

Download references

Acknowledgements

The authors thank three anonymous reviewers and editors for their valuable comments and suggestions.

Code availability

All figures were produced using National Center for Atmospheric Research Command Language (NCL) version 6.6.2 (https://www.ncl.ucar.edu/). All the NCL scripts used in this study are available from the corresponding author upon reasonable request.

Funding

This work was carried out with the support of "Cooperative Research Program for Agriculture Science and Technology Development (Project No. PJ01489102)" Rural Development Administration, Republic of Korea.

Author information

Authors and Affiliations

Authors

Contributions

Joong-Bae Ahn designed the study and revised the manuscript writing. Chan-Yeong Song analyzed the data and wrote the manuscript. All authors contributed to the manuscript review and editing.

Corresponding author

Correspondence to Joong-Bae Ahn.

Ethics declarations

Ethics approval/declarations

Not applicable.

Consent to participate

Not applicable.

Consent for publication

Not applicable.

Conflict of interest

The authors declare no competing interests.

Additional information

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Song, CY., Ahn, JB. Dynamical downscaling using CGCM ensemble average: an application to seasonal prediction for summer precipitation over South Korea. Theor Appl Climatol 152, 757–772 (2023). https://doi.org/10.1007/s00704-023-04404-5

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00704-023-04404-5

Keywords

Navigation