Rojas‐Beltran et al. (2026) The Sierra Barrier Jet and Distribution of Precipitation in Northern California

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

Identification

• Journal: Journal of Geophysical Research Atmospheres
• Year: 2026
• Date: 2026-01-19
• Authors: Yazmina Rojas‐Beltran, Jason M. Cordeira, F. Martin Ralph, Chad W. Hecht
• DOI: 10.1029/2025jd045006

Research Groups

[Not explicitly stated in the abstract.]

Short Summary

This study examines the characteristics of the Sierra Barrier Jet (SBJ) and its influence on cool-season precipitation in Northern California over 23 years, finding that SBJs significantly contribute to precipitation, especially when co-occurring with atmospheric rivers (ARs).

Objective

• To examine the characteristics of the Sierra Barrier Jet (SBJ) and its influence on cool-season precipitation in Northern California.

Study Configuration

• Spatial Scale: Northern California, including the Sierra, Central Valley, Mt. Shasta–Trinity Alps region, coastal ranges, and specific locations like San Francisco and Oroville (39.5°N, 121.6°W).
• Temporal Scale: 23 cool seasons (October 2000–March 2023).

Methodology and Data

• Models used: Not explicitly stated.
• Data sources: Wind profiler data, precipitation data, and atmospheric river (AR) characteristics including Integrated Water Vapor Transport (IVT).

Main Results

• 439 Sierra Barrier Jet (SBJ) events were identified.
• The mean maximum SBJ wind speed was 25.6 m/s parallel to the Sierra.
• The average SBJ duration was 14.2 hours.
• The typical altitude of maximum SBJ wind was near 1.05 km.
• 65% of 220 landfalling atmospheric rivers (ARs) at San Francisco contained an SBJ.
• 43% of SBJs occurred during a landfalling AR at San Francisco.
• Stronger SBJs tended to coincide with higher Integrated Water Vapor Transport (IVT) and stronger ARs.
• ARs with higher IVT values more frequently contained an SBJ.
• SBJ events accounted for up to 40% of cool-season precipitation, with maxima from the coast north of San Francisco through the Central Valley and into the Mt. Shasta–Trinity Alps region.
• AR events contributed up to 50% of cool-season precipitation, with a similar spatial pattern.
• When SBJs and ARs occurred together, they produced more than 30% of the seasonal precipitation, with maxima across the coastal ranges and into the northern Central Valley.
• SBJs and ARs enhanced precipitation over the northern Central Valley, the Sierra, and the Mt. Shasta–Trinity Alps region.

Contributions

• Provides a long-term (23 cool seasons) climatological analysis of Sierra Barrier Jet (SBJ) characteristics and their influence on precipitation in Northern California.
• Quantifies the co-occurrence of SBJs with atmospheric rivers (ARs) and their combined impact on regional precipitation.
• Offers detailed spatial insights into the precipitation contributions from SBJs, ARs, and their synergy across various regions of Northern California.

Funding

[Not explicitly stated in the abstract.]

Citation

@article{RojasBeltran2026Sierra,
  author = {Rojas‐Beltran, Yazmina and Cordeira, Jason M. and Ralph, F. Martin and Hecht, Chad W.},
  title = {The Sierra Barrier Jet and Distribution of Precipitation in Northern California},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2026},
  doi = {10.1029/2025jd045006},
  url = {https://doi.org/10.1029/2025jd045006}
}