Tang et al. (2025) Effects of Typhoon Fitow residual circulation on the relationship between surface wind field and precipitation in Shanghai

Identification

• Journal: Scientific Reports
• Year: 2025
• Date: 2025-12-31
• Authors: Y. Tang, Jishi Zhang, Caijun Yue, Juan Sun, Zhihui Han, Gu Wen, Liping Deng, Yao Yao
• DOI: 10.1038/s41598-025-33915-6

Research Groups

• Shanghai Ecological Forecasting and Remote Sensing Center, Shanghai, China
• Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, China
• Shanghai Marine Meteorological Center, Shanghai, China
• Shanghai Meteorological Information and Technology Support Center, Shanghai, China
• Laboratory for Coastal Ocean Variation and Disaster Prediction, College of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang, China

Short Summary

This study investigates the relationship between surface wind fields and the spatially inhomogeneous heavy precipitation in Shanghai, triggered by Typhoon Fitow's residual circulation, demonstrating how the urban underlying surface modifies wind patterns and enhances local convergence.

Objective

• To investigate the relationship between the surface wind field and the spatially inhomogeneous heavy precipitation in Shanghai, triggered by Typhoon Fitow's residual circulation, and to further explore the possible impact of Shanghai's urban underlying surface on this heavy precipitation process.

Study Configuration

• Spatial Scale: Shanghai, China (30.6–31.9°N, 120.6–122.2°E), focusing on the Shanghai Central Area (SCA) and its four surrounding regions (R1, R2, R3, R4).
• Temporal Scale: October 7 to 8, 2013, with a specific study period from 17:00 UTC 7 to 04:00 UTC 8 October 2013.

Methodology and Data

• Models used:
  • Multi-physical diagnostic analysis.
  • One-layer non-geostrophic Q vector divergence method.
• Data sources:
  • Automatic Weather Stations (AWS) observations (129 stations in Shanghai): hourly rainfall, 2-minute mean wind speed, 2-minute mean wind direction, and dew point temperature (00:00 UTC 7 to 23:00 UTC 8 October 2013).
  • China Meteorological Administration (CMA) typhoon track data: intensity and track of Typhoon Fitow (2013) (6-hour temporal resolution).
  • FY-2E satellite infrared (10.3-11.3 µm) bright temperature product (from National Satellite Meteorological Center, NSMC).
  • ECMWF Re-Analyses (ERA5): hourly relative humidity and horizontal wind data on pressure levels (0.25° x 0.25° spatial resolution, 1-hour temporal resolution, 00:00 UTC 7 to 23:00 UTC 8 October 2013).

Main Results

• The Shanghai Central Area (SCA) decelerated the eastward progression of the northerly wind associated with Typhoon Fitow's residual circulation.
• A low-wind area (below 2.0 m/s) and wind deflection around the SCA enhanced surface wind field convergences in its surrounding regions.
• Slow-moving convective systems prolonged rainfall duration, while wind deflection around the SCA further strengthened surface wind convergence conditions.
• Intense surface Q vector convergence (stronger than -0.3×10^-13 Pa^-1 s^-3) persisted around the SCA, serving as a reliable indicator for precipitation development; precipitation attenuated rapidly within 2 hours following the weakening of this convergence.
• Surface water vapor advection was channeled by wind deflection around the SCA, leading to water vapor accumulation in both upwind and downwind areas of the SCA.
• The SCA and its upwind (R1) and downwind (R3) areas experienced rainstorms for approximately 3 hours, exhibiting greater intensity and longer duration compared to other regions of Shanghai.

Contributions

• This study provides the first dedicated research on the correspondence between surface wind fields, precipitation, and the urban underlying surface in Shanghai during a typhoon residual circulation event.
• It offers valuable insights into how Shanghai's urban underlying surface impacts local wind fields and water vapor transport, explaining the spatial inhomogeneity distribution of heavy precipitation.

Funding

• National Natural Science Foundation of China [grant numbers 41875059, 41875071]
• Shanghai Natural Science Foundation [grant numbers 22ZR1456100, 21ZR1457700]

Citation

@article{Tang2025Effects,
  author = {Tang, Y. and Zhang, Jishi and Yue, Caijun and Sun, Juan and Han, Zhihui and Wen, Gu and Deng, Liping and Yao, Yao},
  title = {Effects of Typhoon Fitow residual circulation on the relationship between surface wind field and precipitation in Shanghai},
  journal = {Scientific Reports},
  year = {2025},
  doi = {10.1038/s41598-025-33915-6},
  url = {https://doi.org/10.1038/s41598-025-33915-6}
}