Chen et al. (2025) Contrasting mechanisms of cross-regional heavy precipitation induced by an eastward-moving Tibetan Plateau vortex: Dynamical dominance versus thermodynamic maintenance

Identification

• Journal: Atmospheric Research
• Year: 2025
• Date: 2025-11-20
• Authors: Yingyi Chen, Weiqiang Ma, Jianan He, Wenqing Zhao, Mingxin Sun, Yaoming Ma
• DOI: 10.1016/j.atmosres.2025.108634

Research Groups

• College of Atmospheric Science, Lanzhou University
• Land-Atmosphere Interaction and its Climatic Effects Group, State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences
• Kathmandu Center of Research and Education, Chinese Academy of Sciences
• College of Earth and Planetary Sciences, University of Chinese Academy of Sciences
• National Observation and Research Station for Qomolongma Special Atmospheric Processes and Environmental Changes
• Anhui Meteorological Observatory
• College of Hydraulic & Environmental Engineering, China Three Gorges University
• China-Pakistan Joint Research Center on Earth Sciences, Chinese Academy of Sciences

Short Summary

This study investigates the contrasting dynamical and thermodynamic mechanisms of heavy precipitation induced by an eastward-moving Tibetan Plateau Vortex (TPV) across the Eastern Slope of the TP (ESTP) and the North China Plain (NCP). It reveals that ESTP precipitation is driven by a coupled dynamical-thermodynamic mechanism, while NCP precipitation is dominated by dynamical forcing, highlighting an asymmetrical coupling framework.

Objective

• To systematically contrast the dynamical-thermodynamic coupling mechanisms of an eastward-propagating Tibetan Plateau Vortex (TPV) that triggered a cross-regional heavy precipitation event (8–13 July 2021) over the Eastern Slope of the Tibetan Plateau (ESTP) and the North China Plain (NCP).

Study Configuration

• Spatial Scale: Regional to synoptic scale, focusing on the Tibetan Plateau (TP), Eastern Slope of the TP (ESTP: 29.5°N–33.5°N, 105.5°E–109.5°E), and North China Plain (NCP: 36.5°N–40.5°N, 115.5°E–119.5°E). The TPV dataset covers 70°E–110°E, 25°N–40°N.
• Temporal Scale: A specific heavy precipitation event from 8–13 July 2021. The TPV dataset used for identification covers 1979–2021.

Methodology and Data

• Models used:
  • Potential Vorticity (PV) equation in isobaric coordinates for dynamical and thermodynamic diagnostics.
  • Tendency equation of stratification stability.
  • Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) backward trajectory model for moisture transport pathways.
• Data sources:
  • Database of the Tibetan Plateau vortex (1979–2021).
  • China Meteorological Administration Land Data Assimilation System (CLDAS-V2.0) for gridded precipitation (0.0625° × 0.0625°, hourly).
  • FY-2G geostationary satellite Black Body Temperature (TBB) data (0.1° × 0.1°, daily).
  • ERA5 reanalysis data (0.25° × 0.25°, hourly) for atmospheric circulation fields (geopotential height, air temperature, wind components, specific humidity, PV).
  • Global Data Assimilation System (GDAS) for HYSPLIT wind fields.

Main Results

• The TPV-induced heavy precipitation event (8–13 July 2021) exhibited two distinct centers over the ESTP and NCP, with contrasting dynamical-thermodynamic coupling mechanisms.
• Over the ESTP, heavy precipitation resulted from a dynamical-thermodynamic coupled mechanism. Low-level jets from the Indian Ocean and South China Sea, combined with orographic lifting, triggered warm and moist advection, which was further enhanced by PV advection and diabatic heating. Precipitation peaks coincided with mid-tropospheric PV maxima, with diabatic heating providing a sustained PV source.
• Over the NCP, a dual-channel moisture transport pathway emerged as the TPV interacted with the Western Pacific Subtropical High (WPSH). Precipitation peaks preceded PV maxima, indicating a dynamically dominated regime where PV advection accounted for over 70% of the local PV tendency. Moisture originated more from the Western North Pacific.
• Latent heating rapidly amplified nascent convection, and thermal processes enhanced low-level instability, compensating for weakening dynamical forcing and sustaining precipitation.
• The study establishes a "dynamical-thermodynamic coupling asymmetry" framework, where regional disparities in TPV-induced heavy precipitation arise from multiscale interactions and distinct topographic settings.

Contributions

• Proposes a novel "dynamical-thermodynamic coupling asymmetry" framework to explain cross-regional heavy precipitation induced by eastward-propagating TPVs.
• Elucidates the intrinsic causes of the asymmetric distribution between precipitation and PV maxima during TPV propagation, unifying dynamical forcing and thermodynamic feedback within a coherent energy-coupling system.
• Reconceptualizes TPVs as active mesoscale systems that modulate regional moisture and energy transport through bidirectional coupling with background flows, rather than passive disturbances.
• Provides a physical basis for improving the parameterization and prediction of TPV-related heavy precipitation, particularly in identifying precursor signals and refining simulated PV-precipitation phase configurations.
• Highlights the critical role of TPVs in linking energy anomalies over the Tibetan Plateau with downstream extreme precipitation, contributing to a new physical foundation for understanding the Asian water cycle.

Funding

• Major Science and Technology Project of the Xizang Autonomous Region (XZ202402ZD0006 and XZ202401JD0004)
• National Natural Science Foundation of China (U2242208)

Citation

@article{Chen2025Contrasting,
  author = {Chen, Yingyi and Ma, Weiqiang and He, Jianan and Zhao, Wenqing and Sun, Mingxin and Ma, Yaoming},
  title = {Contrasting mechanisms of cross-regional heavy precipitation induced by an eastward-moving Tibetan Plateau vortex: Dynamical dominance versus thermodynamic maintenance},
  journal = {Atmospheric Research},
  year = {2025},
  doi = {10.1016/j.atmosres.2025.108634},
  url = {https://doi.org/10.1016/j.atmosres.2025.108634}
}