Guo et al. (2026) Changes in the tropical rainfall seasonal cycle dominated by mesoscale convective systems

Identification

• Journal: Nature Geoscience
• Year: 2026
• Date: 2026-08-14
• Authors: Xiaojie Guo, Guangxing Lin, Fengfei Song, Xuyang Guo, Zhe Feng, Xi Chen, Wenbin Kou, Yang Gao, Jinyan Song, Wei Liao, Feiya Bi, Chenglai Wu, Aiguo Dai
• DOI: 10.1038/s41561-026-02072-4

Research Groups

• Global Change Research Center, Xiamen University
• Ocean University of China
• National Center for Atmospheric Research
• University of California, Los Angeles
• Chinese Academy of Sciences
• University of Colorado Boulder

Short Summary

This study investigates the impact of global warming on tropical rainfall seasonality using a high-resolution Earth system model coupled to a multiscale modeling framework. The results show that mesoscale convective systems (MCSs) dominate the future changes in both the amplitude and phase of tropical precipitation seasonal cycle.

Objective

• Investigate how global warming affects the tropical rainfall seasonal cycle, particularly the role of mesoscale convective systems (MCSs).

Study Configuration

• Spatial Scale: Global scale with a focus on the tropics (25° S to 25° N)
• Temporal Scale: Decade-long simulations with a 10-year historical and high-warming experiment

Methodology and Data

• Models used: Community Earth System Model version 1 (CESM-MMF) with a multiscale modeling framework (MMF)
• Data sources: Satellite, observation, reanalysis data from various sources

Main Results

• The amplitude of tropical precipitation seasonal cycle increases by 38–45% and the phase is delayed by 10–15 days under high-emission scenario.
• Mesoscale convective systems (MCSs) dominate the future changes in both the amplitude and phase of tropical precipitation seasonal cycle.
• The delay arises from fewer early season MCSs associated with slower seasonal migration of the Hadley cell, whereas amplification is driven mainly by increased rainfall intensity within these systems.

Contributions

• This study provides new evidence for shifts in both the phase and amplitude of the tropical rainfall seasonal cycle under global warming.
• It highlights the critical role of mesoscale convective systems (MCSs) in translating large-scale changes into the tropical rainfall seasonal cycle.

Funding

• National Natural Science Foundation of China (Grant No. 42175046)
• National Key Research and Development Program of China (Grant No. 2021YFA0609900)
• National Center for Atmospheric Research (NCAR) funding

Citation

@article{Guo2026Changes,
  author = {Guo, Xiaojie and Lin, Guangxing and Song, Fengfei and Guo, Xuyang and Feng, Zhe and Chen, Xi and Kou, Wenbin and Gao, Yang and Song, Jinyan and Liao, Wei and Bi, Feiya and Wu, Chenglai and Dai, Aiguo},
  title = {Changes in the tropical rainfall seasonal cycle dominated by mesoscale convective systems},
  journal = {Nature Geoscience},
  year = {2026},
  doi = {10.1038/s41561-026-02072-4},
  url = {https://doi.org/10.1038/s41561-026-02072-4}
}