Takami et al. (2026) Hill‐Terrain Modulation of Inland Snow‐Cloud Microphysics: Polarimetric Radar and Balloon‐Borne Particle Imaging Radiosonde Observations

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

Identification

• Journal: Geophysical Research Letters
• Year: 2026
• Date: 2026-04-03
• Authors: Kazuya Takami, K. Suzuki, Yutaka HARA, Y. Fujimori
• DOI: 10.1029/2025gl121149

Research Groups

Not specified in the abstract.

Short Summary

This study investigated snow-cloud microphysics over inland hills in Japan, revealing that even modest terrain significantly modulates snow-particle growth and graupel formation through various atmospheric processes.

Objective

• To understand how snow-cloud microphysics and snow-particle growth processes are modulated by modest inland hills, and to identify the specific mechanisms influencing graupel formation in such environments.

Study Configuration

• Spatial Scale: Regional scale, focused on Tokamachi City, Niigata Prefecture, Japan, specifically around Uonuma Hill (approximately 700 m above sea level).
• Temporal Scale: Winter season of 2024–2025.

Methodology and Data

• Models used: None explicitly mentioned; observational study.
• Data sources:
  • Four launches of a newly developed balloon-borne particle-imaging radiosonde (Rainscope).
  • Dual X-band polarimetric radars deployed on both sides of Uonuma Hill.
  • Coordinated observations.

Main Results

• Snow-particle growth processes showed marked differences depending on whether airflow passed over or was blocked by the hills.
• Graupel formation is influenced by multiple mechanisms: advection from coastal convective clouds, orographic ascent along slopes, mountain-wave propagation leeward of the hills, and seeder-feeder interactions upstream.
• Even modest inland terrain can substantially modulate snow-cloud microphysics.

Contributions

• Demonstrates the significant and complex role of modest inland terrain in modulating snow-cloud microphysics and winter precipitation, distinguishing it from high mountain systems.
• Provides detailed observational evidence of specific atmospheric mechanisms (advection, orographic ascent, mountain waves, seeder-feeder interactions) influencing graupel formation over hills.
• Utilizes a newly developed balloon-borne particle-imaging radiosonde (Rainscope) in coordinated observations to gather microphysical data.

Funding

Not specified in the abstract.

Citation

@article{Takami2026HillTerrain,
  author = {Takami, Kazuya and Suzuki, K. and HARA, Yutaka and Fujimori, Y.},
  title = {Hill‐Terrain Modulation of Inland Snow‐Cloud Microphysics: Polarimetric Radar and Balloon‐Borne Particle Imaging Radiosonde Observations},
  journal = {Geophysical Research Letters},
  year = {2026},
  doi = {10.1029/2025gl121149},
  url = {https://doi.org/10.1029/2025gl121149}
}