Wang et al. (2025) Multi-scale shifts in rainfall patterns in a subtropical region (1981–2024): challenges and implications for water management

Identification

• Journal: Journal of Hydrology
• Year: 2025
• Date: 2025-12-27
• Authors: Hui Wang, Tirusew Asefa, Fikadu Getachew, Yujian Zhou
• DOI: 10.1016/j.jhydrol.2025.134851

Research Groups

• Tampa Bay Water, Clearwater, FL, USA
• Patel College of Global Sustainability, University of South Florida, Tampa, FL, USA
• Department of Statistics, University of California Berkeley, CA, USA

Short Summary

This study analyzed multi-scale rainfall pattern shifts in a subtropical region from 1981 to 2024, revealing increased temporal concentration, more intense sub-daily events, and longer dry spells, which decouple total rainfall volume from its hydrological utility and pose challenges for water management.

Objective

• To analyze long-term, multi-scale changes in rainfall patterns, including total seasonal rainfall, onset/demise dates, concentration, non-rainy days, dry spells, and extremes, to understand their implications for water management in a subtropical region.

Study Configuration

• Spatial Scale: Subtropical region, specifically Central Florida.
• Temporal Scale: Long-term analysis from 1981 to 2024, examining rainfall characteristics across multiple temporal scales (sub-daily, daily, monthly to annual), with a focus on the rainy season.

Methodology and Data

• Models used: Not applicable (no specific hydrological or climate models were used for simulation by the authors).
• Data sources: Hourly NLDAS-2 data.

Main Results

• The average onset of the rainy season is Julian day 148, and the average demise is Julian day 274.
• Temporally concentrated rainfall, with increasingly intense sub-daily events and more frequent non-rainy days during the rainy season, has been observed.
• Afternoon rainfall peaks remain dominant but have become more abrupt in recent years.
• While seasonal rainfall totals remain relatively stable in many areas, these changes signal a growing decoupling between total rainfall volume and its hydrological utility.
• An increasing trend in the Precipitation Concentration Index (PCI) at both daily and sub-daily scales has been observed over the past few decades.
• Intensified rainfall events, longer dry spells, and greater intra-seasonal variability could pose significant challenges to water resources management.

Contributions

• Provides a comprehensive temporal analysis of rainfall characteristics across multiple scales (sub-daily to annual) in a subtropical region.
• Highlights the limitations of relying solely on rainfall totals for assessing water availability and security.
• Emphasizes the critical importance of incorporating temporal structure metrics, such as the Precipitation Concentration Index (PCI) and dry spell analysis, for effective water management under a changing climate.

Funding

• Not specified in the provided text.

Citation

@article{Wang2025Multiscale,
  author = {Wang, Hui and Asefa, Tirusew and Getachew, Fikadu and Zhou, Yujian},
  title = {Multi-scale shifts in rainfall patterns in a subtropical region (1981–2024): challenges and implications for water management},
  journal = {Journal of Hydrology},
  year = {2025},
  doi = {10.1016/j.jhydrol.2025.134851},
  url = {https://doi.org/10.1016/j.jhydrol.2025.134851}
}