Filippucci et al. (2026) Tracking Summer Greenland Blocking: The Upstream Pathway Shapes Historical Extremes and Future Change

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Identification

• Journal: International Journal of Climatology
• Year: 2026
• Date: 2026-06-16
• Authors: Michele Filippucci, Jacob Maddison, Simona Bordoni
• DOI: 10.1002/joc.70472

Research Groups

Not specified in the provided text.

Short Summary

This study employs a novel Lagrangian tracking tool, blocktrack, to analyze summer Greenland atmospheric blocking (GB) in ERA5 reanalysis and CMIP6 models, identifying distinct types of blocking events and their future projections.

Objective

• To investigate the representation and future evolution of summer Greenland atmospheric blocking from a Lagrangian perspective, specifically focusing on trajectories, intensities, and wave-breaking patterns.

Study Configuration

• Spatial Scale: Regional (Greenland, Northern Canada, and the North Atlantic).
• Temporal Scale: Summer season; historical analysis (ERA5) and future projections (CMIP6 under the SSP3-7.0 scenario).

Methodology and Data

• Models used: CMIP6 model ensemble and the blocktrack Python package for Lagrangian tracking.
• Data sources: ERA5 reanalysis.

Main Results

• Classification of GB: Blocking events are categorized into two types:
  • Upstream blocks: Originate in Northern Canada, characterized by anticyclonic wave breaking, stronger moisture transport, and higher temperature anomalies.
  • Retrograding blocks: Follow an east-to-west trajectory originating in the North Atlantic, characterized by cyclonic wave breaking.
• Observed Trends: The recent increase in GB frequency (notably in 2012) is primarily driven by upstream blocks.
• Model Performance: CMIP6 models generally underestimate GB variability and fail to capture the observed increase in frequency, particularly for the upstream component.
• Future Projections (SSP3-7.0): Results indicate a decline in retrograding blocks and a potential increase in upstream blocks.
• Drivers: Changes are linked to jet stream shifts, increased high-moisture transport from low to high latitudes, Atlantic Multidecadal Variability, and Arctic Amplification.

Contributions

The study introduces a Lagrangian diagnostic approach using the blocktrack package, allowing for the differentiation of Greenland blocking events by their trajectories and wave-breaking characteristics, which provides deeper insight into the dynamics and drivers of these events than traditional Eulerian methods.

Funding

Not specified in the provided text.

Citation

@article{Filippucci2026Tracking,
  author = {Filippucci, Michele and Maddison, Jacob and Bordoni, Simona},
  title = {Tracking Summer Greenland Blocking: The Upstream Pathway Shapes Historical Extremes and Future Change},
  journal = {International Journal of Climatology},
  year = {2026},
  doi = {10.1002/joc.70472},
  url = {https://doi.org/10.1002/joc.70472}
}