Singh et al. (2026) Global shifts in rainfall drought relationship: weakening association in tropics

Identification

• Journal: Journal of Hydrology
• Year: 2026
• Date: 2026-03-01
• Authors: Gauranshi Raj Singh, C.T. Dhanya, Aniket Chakravorty
• DOI: 10.1016/j.jhydrol.2026.135240

Research Groups

• Department of Civil Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, India
• North Eastern Space Applications Centre, Department of Space, India

Short Summary

This study examines global meteorological drought dynamics from 1951 to 2016, revealing a sixfold increase in global drought frequency, particularly in tropical and subtropical regions. It finds that increased rainfall variability, rather than just rainfall deficit, is increasingly driving these droughts, leading to a 60 % rise in drought likelihood even during surplus rainfall years.

Objective

• To examine global meteorological drought dynamics and assess whether the precipitation–drought linkage has changed, and to conduct an attribution analysis to identify the dominant climatic drivers.

Study Configuration

• Spatial Scale: Global, with a focus on Tropical and Subtropical regions.
• Temporal Scale: 1951–2016 (66 years).

Methodology and Data

• Models used: Not explicitly mentioned; analysis of meteorological drought dynamics using drought index values.
• Data sources: Not explicitly mentioned, likely global meteorological datasets used for drought index calculation.

Main Results

• Global drought frequency increased up to six times between 1951 and 2016.
• This increase was predominant post-1980s, concentrated in Tropical and Subtropical regions.
• The traditional link between drought events and rainfall deficit has weakened.
• Drought likelihood during surplus rainfall years rose by 60 %.
• Drought-prone hotspots experienced a 40 % increase in meteorological droughts despite relatively stable total precipitation.
• Increased variability in precipitation distribution is the primary driver, leading to significant drought events with drought index values falling below -1.
• This impact is profound in the Tropical zone, affecting diverse climates.

Contributions

• Demonstrates that precipitation variability, rather than mean rainfall deficit alone, is increasingly driving tropical drought dynamics.
• Reshapes the understanding of hydroclimate behavior and risk in Earth-system contexts.
• Provides vital insights for modifying drought early-warning systems and water planning measures.

Funding

• Not specified in the provided text.

Citation

@article{Singh2026Global,
  author = {Singh, Gauranshi Raj and Dhanya, C.T. and Chakravorty, Aniket},
  title = {Global shifts in rainfall drought relationship: weakening association in tropics},
  journal = {Journal of Hydrology},
  year = {2026},
  doi = {10.1016/j.jhydrol.2026.135240},
  url = {https://doi.org/10.1016/j.jhydrol.2026.135240}
}