Mu et al. (2025) Impacts of Northerly Low-Level Jets on Mesoscale Convective Systems East of the Andes

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

Identification

• Journal: Repository for Publications and Research Data (ETH Zurich)
• Year: 2025
• Date: 2025-11-08
• Authors: Mu, Ye, Jones, Charles, Carvalho, Leila M.V., Kukulies, Julia, Prein, Andreas F., Xue, Lulin, Liu, Changhai, Prein, Andreas F.
• DOI: 10.3929/ethz-c-000787006

Research Groups

[Information not provided in the paper text.]

Short Summary

This study investigates the distinct impacts of three types of low-level jets (Central, Northern, and Andes) on Mesoscale Convective Systems (MCSs) across South America using a 4 km Weather Research and Forecasting (WRF) model simulation and satellite data. It finds that Central and Andes LLJs significantly enhance MCS activity and heavy precipitation over the La Plata Basin, while the Northern LLJ has a weaker, more scattered impact over the Amazon Basin, with stronger LLJs supporting larger, longer-lived MCSs modulated by ENSO.

Objective

• To examine the impacts of three types of low-level jets (Central, Northern, and Andes) on Mesoscale Convective Systems (MCSs) in South America.

Study Configuration

• Spatial Scale: South America, specifically focusing on the La Plata Basin (LPB), Amazon Basin, and the eastern slopes of the northern Andes. The model uses a 4 km horizontal grid spacing.
• Temporal Scale: The study analyzes relationships modulated by the El Niño Southern Oscillation, implying a multi-year or climatological analysis period, though the specific duration of the WRF simulation is not explicitly stated.

Methodology and Data

• Models used: Weather Research and Forecasting (WRF) model.
• Data sources: Satellite-based data, and IMERG (Integrated Multi-satellitE Retrievals for GPM) for comparison.

Main Results

• The Central and Andes LLJ types facilitate significant moisture flux convergence over the La Plata Basin, contributing to intense MCS activity and heavy precipitation.
• The Northern LLJ type, operating over the eastern slopes of the northern Andes, exerts a weaker impact on MCS development over the Amazon Basin, leading to more scattered convection.
• Stronger LLJs support larger, longer-lived MCSs with higher mean precipitation in jet exit regions.
• The El Niño Southern Oscillation modulates these relationships: El Niño increases MCS size and duration in the Central LLJ region, while La Niña enhances MCS frequency in the Andes and Northern LLJ regions.
• The WRF model captures many of these dynamics but produces higher extreme MCS mean precipitation than IMERG.

Contributions

• Highlights the critical importance of low-level jet variability in modulating Mesoscale Convective Systems across South America.
• Suggests that future changes in low-level jets could significantly alter the hydroclimate and extreme weather patterns in the region.
• Underscores the utility of kilometre-scale models in representing the complex interactions of low-level jets and Mesoscale Convective Systems, positioning them as a promising tool for understanding these interactions and assessing climate change impacts on water resources and extreme weather.

Funding

[Information not provided in the paper text.]

Citation

@article{Mu2025Impacts,
  author = {Mu, Ye and Jones, Charles and Carvalho, Leila M.V. and Kukulies, Julia and Prein, Andreas F. and Xue, Lulin and Liu, Changhai and Prein, Andreas F.},
  title = {Impacts of Northerly Low-Level Jets on Mesoscale Convective Systems East of the Andes},
  journal = {Repository for Publications and Research Data (ETH Zurich)},
  year = {2025},
  doi = {10.3929/ethz-c-000787006},
  url = {https://doi.org/10.3929/ethz-c-000787006}
}