Tong et al. (2025) Changes in persistent anticyclonic circulation across Eurasian continent and its linkage with extreme heatwaves

Identification

• Journal: Global and Planetary Change
• Year: 2025
• Date: 2025-11-15
• Authors: Yiying Tong, Cheng Sun, Wei Lou, Menghao Dong, Linfeng Shi, Zichen Song, Yihua He
• DOI: 10.1016/j.gloplacha.2025.105183

Research Groups

• State Key Laboratory of Remote Sensing and Digital Earth, Faculty of Geographical Science, Beijing Normal University, Beijing, China
• Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing 21044, China

Short Summary

This study develops an objective framework to identify Persistent Anticyclonic Circulation (PAC) events across Eurasia from 1979 to 2023, revealing that while overall PAC frequency shows no trend, long-lived PAC events (≥7 days) have significantly intensified and expanded, exhibiting heterogeneous impacts on extreme heatwaves across different latitudes.

Objective

• To develop an objective framework for identifying Persistent Anticyclonic Circulation (PAC) events across Eurasia.
• To analyze the spatiotemporal evolution of PAC events and their mechanistic linkages with extreme heatwaves across the Eurasian continent, particularly under global warming.

Study Configuration

• Spatial Scale: Eurasian continent, with specific regional analysis for mid-to-high latitudes (> 45°N, e.g., northwestern Eurasia) and subtropical regions (< 45°N, e.g., Central Asia).
• Temporal Scale: Warm seasons from 1979 to 2023 (45 years). PAC events are defined as lasting ≥3 days, with a focus on long-lived events lasting ≥7 days.

Methodology and Data

• Models used: An objective framework was developed for identifying PAC events based on persistence criteria. No specific climate simulation models (e.g., GCMs, RCMs) were mentioned for generating data.
• Data sources: Mean sea level pressure (MSLP) data.

Main Results

• The frequency and accumulated days of overall PAC events across Eurasia show no significant temporal trends from 1979 to 2023.
• The mean duration of PAC events has increased substantially (p < 0.1).
• Long-lived PAC events (lasting ≥7 days) show significant upward trends in both occurrence frequency and accumulated days.
• A continuous and significant expansion of the affected areas and markedly enhanced persistence characteristics are observed for long-lived PAC events.
• Distinct latitudinal patterns of PAC event impacts are identified:
  • In mid-to-high latitudes (> 45°N), particularly northwestern Eurasia, PAC events show significant increases in accumulated days and duration, with robust correlations with extreme climate indices. This is driven by a coupled dynamical-thermal feedback mechanism (enhanced atmospheric stability, subsidence, reduced cloud cover, increased surface radiation).
  • In subtropical regions (< 45°N), especially Central Asia, PAC events exhibit decreasing trends and inverse correlations with climate extremes, attributed to global warming effects (uniform vertical warming and enhanced upward motion weakening anticyclonic influence).

Contributions

• Development of an objective and robust framework for identifying Persistent Anticyclonic Circulation (PAC) events.
• First comprehensive spatiotemporal analysis of PAC events across the Eurasian continent over a 45-year period (1979-2023).
• Identification of the significant intensification, expansion, and increased persistence of long-lived PAC events, indicating a fundamental shift in these weather systems.
• Revelation of spatially heterogeneous relationships between PAC events and extreme weather across different latitudes in Eurasia, providing critical insights into regional climate dynamics.
• Advancement of the understanding of heat-related extreme events and their drivers under global warming.

Funding

Not mentioned in the provided text.

Citation

@article{Tong2025Changes,
  author = {Tong, Yiying and Sun, Cheng and Lou, Wei and Dong, Menghao and Shi, Linfeng and Song, Zichen and He, Yihua},
  title = {Changes in persistent anticyclonic circulation across Eurasian continent and its linkage with extreme heatwaves},
  journal = {Global and Planetary Change},
  year = {2025},
  doi = {10.1016/j.gloplacha.2025.105183},
  url = {https://doi.org/10.1016/j.gloplacha.2025.105183}
}