Cao et al. (2026) Impact of boundary layer schemes in RegCM-Chem on East Asian climate and its response to the aerosol-radiation interaction

Identification

• Journal: Atmospheric Research
• Year: 2026
• Date: 2026-03-23
• Authors: Heng Cao, Bingliang Zhuang, Yinan Zhou, Peng Gao, Yaxin Hu, Tijian Wang, Shu Li, Mengmeng Li, Min Xie, Qian Liu
• DOI: 10.1016/j.atmosres.2026.108951

Research Groups

• School of Atmospheric Sciences, Nanjing University, Nanjing, China
• School of Environment, Nanjing Normal University, Nanjing, China
• Jiangsu Key Laboratory of Environmental Engineering, Jiangsu Academy of Environmental Sciences, Nanjing, China

Short Summary

This study evaluates the Holtslag and University of Washington planetary boundary layer schemes in RegCM-Chem over East Asia to understand their impact on aerosol-radiation interactions and regional climate. It finds that the UW scheme better reproduces observations and yields a stronger surface effective radiative forcing compared to the Holtslag scheme, highlighting the importance of PBL parameterization.

Objective

• To evaluate the Holtslag and University of Washington planetary boundary layer schemes in RegCM-Chem to better understand the uncertainties of aerosol–radiation interactions (ARIs) over East Asia and their impact on regional climate responses.

Study Configuration

• Spatial Scale: East Asia
• Temporal Scale: Regional climate assessment (specific period not detailed in provided text)

Methodology and Data

• Models used: RegCM-Chem, employing Holtslag (Hol) and University of Washington (UW) planetary boundary layer schemes.
• Data sources: Observations, reanalysis products.

Main Results

• Both Holtslag and UW schemes can reproduce spatiotemporal variations in climate variables, with the UW scheme aligning better with observations for near-surface temperature, humidity, and wind speed.
• The UW scheme generally produces greater total cloud cover (exceeding the Holtslag scheme by up to 10%), accompanied by lower surface temperatures, a shallower boundary layer height, and a drier surface in the central to eastern region compared to the Holtslag scheme.
• The UW scheme yields higher surface anthropogenic aerosol concentrations in central and eastern coastal regions due to weaker wet removal, lower boundary layer height, and stronger convergence.
• The Holtslag scheme produces higher dust surface concentrations from stronger emissions.
• Enhanced vertical transport in the UW scheme elevates aerosols aloft, leading to higher vertical aerosol concentrations and optical depth, with aerosol loadings closer to observations or reanalysis products.
• The UW scheme produces a stronger surface effective radiative forcing (ERF), with values in the central to eastern region reaching -7.86 W/m², which is approximately 1.1 W/m² stronger than those from the Holtslag scheme.
• The Holtslag scheme might underestimate the climate response to aerosol-radiation interaction over East Asia.

Contributions

• This study highlights the critical importance of planetary boundary layer parameterization choice for reliable regional climate assessment and aerosol impact studies, particularly concerning aerosol-radiation interactions over East Asia.
• It provides a detailed comparison of two widely used PBL schemes within RegCM-Chem, identifying the UW scheme as more consistent with observations and leading to a stronger estimated aerosol-radiation interaction effect.

Funding

• [No funding information provided in the paper text.]

Citation

@article{Cao2026Impact,
  author = {Cao, Heng and Zhuang, Bingliang and Zhou, Yinan and Gao, Peng and Hu, Yaxin and Wang, Tijian and Li, Shu and Li, Mengmeng and Xie, Min and Liu, Qian},
  title = {Impact of boundary layer schemes in RegCM-Chem on East Asian climate and its response to the aerosol-radiation interaction},
  journal = {Atmospheric Research},
  year = {2026},
  doi = {10.1016/j.atmosres.2026.108951},
  url = {https://doi.org/10.1016/j.atmosres.2026.108951}
}