Characteristics of quasi-stationary Southwest Vortex and its mechanisms affecting precipitation
- 1Heavy Rain and Drought-Flood Disasters in Plateau and Basin Key Laboratory of Sichuan Province, Institute of Tibetan Plateau Meteorology, China Meteorological Administration
Abstract
This study compares five quasi-stationary Southwest Vortex (SWV) events that induced heavy rainfall, using the CRA40 reanalysis data from the China Meteorological Administration. Results indicate that the Tibetan Plateau’s topography and the strong westward-extending Western Pacific subtropical high (WPSH) act as critical blocking factors, stabilizing the SWV in the Sichuan-Chongqing region. Depending on the WPSH configuration, two types of quasi-stationary SWV processes are identified: north–south and east–west distributions. Long stagnation of the SWV is linked to regional heavy precipitation. North–south SWV processes generally exhibit a larger rainfall range and stronger intensity than east–west processes. They feature significantly higher total column water vapor content and stronger, wider southwesterly airflow. The strongest water vapor transport band around 800 hPa is the main moisture source. Both types occur within a favorable synoptic environment of cyclonic vorticity, low-level convergence, and ascending motion, where vertical velocity plays an important role in modulating precipitation intensity. The combined forcing of the Tibetan Plateau and the WPSH, along with direct impacts from moisture flux convergence and vertical motion, governs the anomalous evolution of quasi-stationary SWVs and their resultant precipitation.
Related
- Added Value of CESM ‐Driven WRF for Mean and Extreme Precipitation Over Complex Terrain in Southwest Asia
- Organic amendments enhance aggregate stability of yellow soils in southwest China: roles of SOC characteristics and Fe oxides
- Evaporation cracking characteristics and mechanism of silt improved by microbial-induced calcium carbonate precipitation
- Movement characteristics of persistent extreme precipitation events over China during the warm season using high spatiotemporal resolution data
- Revisiting the mechanisms for the observed decrease in inner-core tropical cyclone precipitation
BibTeX
@article{chen2026characteristics,
title = {{Characteristics of quasi-stationary Southwest Vortex and its mechanisms affecting precipitation}},
author = {Gong Chen and Ping Lu},
journal = {Scientific Reports},
year = {2026},
month = jul,
doi = {10.1038/s41598-026-60592-w},
url = {https://doi.org/10.1038/s41598-026-60592-w},
note = {CC BY},
}
RIS
TY - JOUR
TI - Characteristics of quasi-stationary Southwest Vortex and its mechanisms affecting precipitation
AU - Gong Chen
AU - Ping Lu
PY - 2026
DA - 2026/07/01
JO - Scientific Reports
DO - 10.1038/s41598-026-60592-w
UR - https://doi.org/10.1038/s41598-026-60592-w
AB - This study compares five quasi-stationary Southwest Vortex (SWV) events that induced heavy rainfall, using the CRA40 reanalysis data from the China Meteorological Administration. Results indicate that the Tibetan Plateau’s topography and the strong westward-extending Western Pacific subtropical high (WPSH) act as critical blocking factors, stabilizing the SWV in the Sichuan-Chongqing region. Depending on the WPSH configuration, two types of quasi-stationary SWV processes are identified: north–south and east–west distributions. Long stagnation of the SWV is linked to regional heavy precipitation. North–south SWV processes generally exhibit a larger rainfall range and stronger intensity than east–west processes. They feature significantly higher total column water vapor content and stronger, wider southwesterly airflow. The strongest water vapor transport band around 800 hPa is the main moisture source. Both types occur within a favorable synoptic environment of cyclonic vorticity, low-level convergence, and ascending motion, where vertical velocity plays an important role in modulating precipitation intensity. The combined forcing of the Tibetan Plateau and the WPSH, along with direct impacts from moisture flux convergence and vertical motion, governs the anomalous evolution of quasi-stationary SWVs and their resultant precipitation.
SN - 2045-2322
ER -