Zhang et al. (2025) Innovative trend analysis of annual and seasonal precipitation in the Pearl river basin, Southern China

Identification

• Journal: Theoretical and Applied Climatology
• Year: 2025
• Date: 2025-10-20
• Authors: Yin Zhang, Pei Liu, Fang Yang, Qiang Wang, Fei Yuan
• DOI: 10.1007/s00704-025-05841-0

Research Groups

• Pearl River Water Resources Research Institute, Pearl River Water Resources Commission
• Key Laboratory of Pearl River Estuary Regulation and Protection of Ministry of Water Resources
• Key Laboratory for Water Security in the Guangdong-Hongkong-Macao, Greater Bay Area (Preparatory)
• School of Civil Engineering, Tsinghua University

Short Summary

This study analyzed annual and seasonal precipitation trends in the Pearl River Basin (PRB) from 1959–2018 using Innovative Trend Analysis (ITA) and classical methods, revealing complex regional and seasonal shifts, including increased high precipitation in summer and decreased low precipitation in winter, and highlighting ITA's ability to categorize these trends.

Objective

• To investigate the spatial and temporal variations of annual and seasonal precipitation in the Pearl River Basin (PRB) using three different methods.
• To quantitatively evaluate the trends in low (< 10th percentile), medium (10th–90th percentile), and high (> 90th percentile) precipitation categories.
• To assess the reliability of the Innovative Trend Analysis (ITA) method by comparing it with other methods.

Study Configuration

• Spatial Scale: Pearl River Basin (PRB) in southern China (102°14′–115°53′E; 21°31′–26°49′N), with a drainage area of 4.42 × 10^5 km^2. Sub-areas include the West River Basin (WRB), North River Basin (NRB), East River Basin (ERB), and Pearl River Delta (PRD).
• Temporal Scale: Daily precipitation data from 1959 to 2018 (60 years). Seasonal analysis for spring (March-April-May), summer (June-July-August), autumn (September-October-November), and winter (December-January-February).

Methodology and Data

• Models used:
  • Innovative Trend Analysis (ITA) method
  • Mann-Kendall (MK) test
  • Sen’s Slope
  • Kriging spatial interpolation (for visualizing spatial distribution)
  • Thiessen polygon method (for calculating regional average series)
• Data sources: Daily precipitation data collected from 44 meteorological stations across the Pearl River Basin, provided by the China Meteorological Administration (CMA). Data underwent quality control and homogeneity tests.

Main Results

• Annual Precipitation Trends:
  • Overall, the PRB, WRB, NRB, and ERB exhibited decreasing annual precipitation trends, while the PRD showed an increasing trend.
  • By ITA, the PRB, WRB, NRB, and ERB showed decreasing trends at rates of -0.29, -0.63, -0.60, and -1.57 mm/year, respectively (significant for WRB, NRB, ERB). The PRD showed a significant increasing trend at 2.16 mm/year.
  • ITA revealed a gradual strengthening of the upward trend in precipitation intensity for the PRB and WRB.
  • In the PRB and WRB, low and medium annual precipitation decreased, while high precipitation increased.
  • In the NRB, low and high annual precipitation decreased, while medium precipitation non-significantly increased.
  • In the ERB, low and high annual precipitation showed non-significant increasing trends, while medium precipitation decreased.
  • In the PRD, all precipitation categories (low, medium, high) exhibited increasing trends.
• Seasonal Precipitation Trends:
  • The study area experienced decreasing trends in spring and autumn, contrasting with increasing trends in summer and winter.
  • Spring: Prevalent decreasing trends across most areas. Low spring precipitation significantly increased in the PRD, but trends were not significant in other regions. Medium and high precipitation significantly reduced in the NRB and ERB.
  • Summer: Predominant positive trends. High precipitation showed significant upward trends in the PRB, NRB, and PRD. Low precipitation decreased in the PRB, WRB, NRB, and PRD.
  • Autumn: Characterized by decreasing trends across most areas and categories. High precipitation significantly increased in the NRB, while low and medium precipitation significantly decreased. In the PRD, low precipitation increased, but medium and high precipitation significantly decreased.
  • Winter: Dominated by increasing trends. Low precipitation exhibited decreasing trends in the PRB, WRB, and NRB. All precipitation categories showed increasing trends in the ERB and PRD.
• Methodological Comparison: The ITA method generally aligned with Sen’s Slope for trend direction and with the MK test for increasing/decreasing trends, but ITA detected significant trends at more stations and uniquely provided a visual-graphical representation and categorization of low, medium, and high precipitation trends.

Contributions

• First comprehensive application of the Innovative Trend Analysis (ITA) method to analyze annual and seasonal precipitation trends in the Pearl River Basin, including the categorization of low, medium, and high precipitation.
• Provides detailed insights into the spatial and temporal patterns of precipitation changes, particularly for extreme events (high precipitation for floods, low precipitation for droughts), which are crucial for hazard mitigation and water resource management.
• Confirms the reliability of the ITA method by comparing it with classical trend analysis methods (Mann-Kendall and Sen’s Slope) and demonstrates its superior ability to identify hidden trends and provide categorized trend information.
• Offers valuable information for understanding regional climate vulnerabilities and supporting the formulation of spatially explicit policies to address flood and drought risks in the Pearl River Basin.

Funding

• National Key R&D Program of China (2021YFC3001000)
• Science and Technology Planning Project of Guangzhou (2023A04J1024)
• Basic and Applied Basic Research Foundation of Guangdong Province (2023A1515110764)

Citation

@article{Zhang2025Innovative,
  author = {Zhang, Yin and Liu, Pei and Yang, Fang and Wang, Qiang and Yuan, Fei},
  title = {Innovative trend analysis of annual and seasonal precipitation in the Pearl river basin, Southern China},
  journal = {Theoretical and Applied Climatology},
  year = {2025},
  doi = {10.1007/s00704-025-05841-0},
  url = {https://doi.org/10.1007/s00704-025-05841-0}
}