Wang et al. (2025) Decadal Responses of Global Land Monsoon to Two Surface Thermal Modes in the Last Millennium

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

Identification

• Journal: Journal of Climate
• Year: 2025
• Date: 2025-11-13
• Authors: Zhiyuan Wang, Laurent Li, Feng Hu, Jianglin Wang, Jia Jia
• DOI: 10.1175/jcli-d-25-0296.1

Research Groups

Not explicitly mentioned in the provided text.

Short Summary

This study investigates the influence of global mean surface temperature (GMST) and tropical Pacific temperature gradient (TPTG) on global land monsoon variability over the last millennium (950–1850). It finds that cool-GMST primarily suppresses summer precipitation thermodynamically, while weak-TPTG drives a summer interhemispheric dipole dynamically, with compound conditions largely showing a linear superposition of these distinct effects.

Objective

• To investigate how natural external forcing, specifically changes in global mean surface temperature (GMST) and the tropical Pacific temperature gradient (TPTG), influenced global land monsoon variability at a decadal scale over the last millennium (950–1850).

Study Configuration

• Spatial Scale: Global land monsoon regions, interhemispheric (Northern Hemisphere, Southern Hemisphere), tropical Pacific.
• Temporal Scale: Last millennium (950–1850), decadal scale, summer, winter.

Methodology and Data

• Models used: Not explicitly mentioned in the provided text. A diagnostic with moisture budget decomposition was performed.
• Data sources: Not explicitly mentioned in the provided text. The study investigates past monsoon variability, implying the use of paleoclimate reconstructions or climate model simulations of the past.

Main Results

• Cool Global Mean Surface Temperature (GMST) primarily suppresses summer precipitation via thermodynamic contributions.
• Cool GMST leads to a complex winter response with competing thermodynamic gains and evaporation losses.
• Weak Tropical Pacific Temperature Gradient (TPTG) involves significant dynamic adjustments, driving an interhemispheric dipole for summer land monsoon precipitation: decreases in the Northern Hemisphere (via anomalous subsidence) and increases in the Southern Hemisphere (via thermodynamic contributions and evaporation).
• Enhanced winter monsoon precipitation, especially in the Southern Hemisphere, under weak TPTG is largely driven by dynamics and evaporation.
• Under compound conditions (cool GMST and weak TPTG), the overall monsoon intensity response can be largely interpreted as a linear superposition of the individual drivers.
• Compound conditions result in substantially reduced summer precipitation, primarily due to cooling-induced thermodynamic suppression with additional dynamic contributions.
• The winter response under compound conditions shows a distinct interhemispheric pattern, with precipitation increasing in the Southern Hemisphere and slightly decreasing in the Northern Hemisphere, reflecting different controls by cool GMST and weak TPTG.
• Moisture budget analysis reveals that macroscale linearity emerges from amplified summer drying dominated by cooling-related thermodynamics, and a winter response featuring Southern Hemisphere wetting and Northern Hemisphere slight drying driven by specific thermodynamic and evaporative controls.

Contributions

• Provides a valuable framework for interpreting past monsoon variability and projecting its future variation.
• Demonstrates that GMST and TPTG modulate global land monsoon through distinct physical pathways: GMST primarily via thermodynamic mechanisms, and TPTG via strong dynamic adjustments.
• Shows that the overall global land monsoon intensity response under compound conditions can be largely understood as a linear superposition of individual driver effects, explaining a significant portion of the annual precipitation range anomaly.
• Offers a simplified yet mechanistically grounded framework for interpreting complex climate events (e.g., volcanic eruptions) and improving fundamental understanding of monsoon dynamics and natural climate variability.

Funding

Not explicitly mentioned in the provided text.

Citation

@article{Wang2025Decadal,
  author = {Wang, Zhiyuan and Li, Laurent and Hu, Feng and Wang, Jianglin and Jia, Jia},
  title = {Decadal Responses of Global Land Monsoon to Two Surface Thermal Modes in the Last Millennium},
  journal = {Journal of Climate},
  year = {2025},
  doi = {10.1175/jcli-d-25-0296.1},
  url = {https://doi.org/10.1175/jcli-d-25-0296.1}
}