Santos et al. (2025) Spatial and Temporal Patterns of Rainfall Anomalies and Their Relationship With Global Climate Indices in Rio Grande do Norte, Brazil

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Identification

• Journal: International Journal of Climatology
• Year: 2025
• Date: 2025-11-02
• Authors: Daris Correia dos Santos, Gilmar Bristot, Josemir Araújo Neves
• DOI: 10.1002/joc.70154

Research Groups

Not specified in the provided abstract.

Short Summary

This study analyzed rainfall variability in Rio Grande do Norte, Brazil, using the Rainfall Anomaly Index (RAI) and its relationship with global climate indices (1963–2023). It identified homogeneous rainfall regions and found that teleconnections like AMO, TNA, and Niño indices directly influence rainfall, while LOTI and Solar Flux show an inverse relationship.

Objective

• To analyze the climate variability of the Rainfall Anomaly Index (RAI) and its relationship with global climate indices in Rio Grande do Norte (RN), Brazil.

Study Configuration

• Spatial Scale: Rio Grande do Norte (RN), Brazil.
• Temporal Scale: Monthly data from 1963 to 2023 (61 years).

Methodology and Data

• Models used: Principal Component Analysis (PCA), K-means algorithm, Pearson's correlation coefficient, Wavelet coherence analysis.
• Data sources: Monthly precipitation data from 115 weather stations (observation); Global climate indices (Atlantic Multidecadal Oscillation (AMO), Tropical North Atlantic (TNA), Niño indices, Global Mean Land/Ocean Temperature Index (LOTI), Solar Flux).

Main Results

• Rio Grande do Norte experienced significant changes in precipitation, with both positive and negative anomalies over the decades.
• Principal Component Analysis (PCA) revealed 12 components explaining 73.15% of the total variance in rainfall.
• The K-means algorithm identified three homogeneous rainfall regions corresponding to the state's climatology.
• Teleconnections such as the Atlantic Multidecadal Oscillation (AMO), Tropical North Atlantic (TNA), and Niño indices showed a direct relationship with rainfall patterns.
• The Global Mean Land/Ocean Temperature Index (LOTI) and Solar Flux exhibited an inverse relationship with rainfall, suggesting higher solar radiation and global temperatures are linked to fewer anomalous rains.
• Niño indices showed substantial variation during extreme drought events in 1966, 1982–1983, 1987–1988, 1991–1992, 1997–1998, and 2015–2016.
• Wavelet coherence analysis revealed interannual and interdecadal periodicities in rainfall anomalies, particularly in region R3, which is characterized by low rainfall and frequent droughts.

Contributions

• Provides a comprehensive analysis of rainfall variability and its teleconnections in Rio Grande do Norte, Brazil, over a 61-year period.
• Identifies homogeneous rainfall regions within the state, aiding in localized climate understanding.
• Quantifies the direct and inverse relationships between regional rainfall anomalies and key global climate indices.
• Emphasizes the importance of understanding extreme climate patterns for improved climate prediction and resource management in the region.

Funding

Not specified in the provided abstract.

Citation

@article{Santos2025Spatial,
  author = {Santos, Daris Correia dos and Bristot, Gilmar and Neves, Josemir Araújo},
  title = {Spatial and Temporal Patterns of Rainfall Anomalies and Their Relationship With Global Climate Indices in Rio Grande do Norte, Brazil},
  journal = {International Journal of Climatology},
  year = {2025},
  doi = {10.1002/joc.70154},
  url = {https://doi.org/10.1002/joc.70154}
}