Sah et al. (2026) Spatiotemporal analysis of drought and its teleconnections over agro climatic zones of India

Identification

• Journal: Environmental Earth Sciences
• Year: 2026
• Date: 2026-01-13
• Authors: Sonam Sah, RN Singh, B. Das, Sudhir Kumar Mishra, Yogeshwar Singh, AK Singh, K. Sammi Reddy
• DOI: 10.1007/s12665-025-12791-3

Research Groups

• ICAR-National Institute of Abiotic Stress Management, Baramati, Maharashtra, India
• ICAR-National Bureau of Soil Survey & Land Use Planning, Nagpur, Maharashtra, India
• Rani Lakshmibai Central Agricultural University, Jhansi, Uttar Pradesh, India

Short Summary

This study analyzed long-term spatiotemporal trends of meteorological drought using the Standardized Precipitation Index (SPI) across India's Agro Climatic Zones (ACZs) and investigated its teleconnections with ENSO and IOD. It revealed significant drying trends in central, northern, and eastern India, wetting trends in peninsular India (except western coastal plains), and identified ENSO as the dominant driver of drought variability.

Objective

• To analyze the long-term spatiotemporal trends and variations of meteorological drought over Agro Climatic Zones (ACZs) of India using the Standardized Precipitation Index (SPI).
• To examine the teleconnections between monsoon season meteorological drought and major climate modes, specifically El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD).

Study Configuration

• Spatial Scale: 14 Agro Climatic Zones (ACZs) of India, covering a geographical area of 329 million hectares.
• Temporal Scale:
  • Meteorological drought trend analysis: 1933–2022 (90 years), also analyzed in three 30-year periods (1933–1962, 1963–1992, 1993–2022).
  • Teleconnection analysis with climate modes: 1903–2022 (120 years).
  • Daily rainfall data: 1903–2022.
  • Gridded temperature data: 1951–2022.

Methodology and Data

• Models used:
  • Standardized Precipitation Index (SPI) at 4-month (monsoon SPI-4 for September) and 12-month (annual SPI-12 for December) timescales.
  • Trend analysis methods: Mann-Kendall (MK), modified Mann-Kendall (m-MK), Sen’s slope estimator (SS), simple linear regression (SLR), and Innovative Trend Analysis (ITA).
  • Correlation analysis: Pearson’s correlation coefficient with a two-tailed t-test for significance.
• Data sources:
  • Daily gridded rainfall data (0.25° × 0.25° resolution) from India Meteorological Department (IMD).
  • Gridded temperature data (1° × 1° resolution) from IMD.
  • Monthly anomaly values of climate indices (Niño 3.4, Southern Oscillation Index (SOI), Dipole Mode Index (DMI)) from NOAA’s website.

Main Results

• Monsoon and annual drought frequencies varied from 12.5% to 18.3% across ACZs.
• Long-term (1933–2022) trends of both monsoon SPI-4 and annual SPI-12 showed significant drying tendencies in the central, northern, and eastern parts of India.
• Peninsular India generally exhibited wetting trends, except for the western coastal plains, where significant drying was observed.
• Trend slopes for monsoon SPI-4 (1933–2022) varied from −0.14 to 0.11 per decade, and for annual SPI-12, from −0.14 to 0.19 per decade.
• The Innovative Trend Analysis (ITA) consistently detected significant trends in all ACZs, often where traditional MK/m-MK and SLR tests did not.
• Monsoon SPI-4 in most ACZs was closely linked with ENSO (Niño 3.4 and SOI), showing strong negative correlations (e.g., JJAS average Niño 3.4 correlations up to -0.45).
• The Indian Ocean Dipole (IOD) (DMI) showed almost no significant linkage with monsoon season meteorological drought across ACZs.
• During El Niño years, Niño 3.4 showed the strongest negative correlations with monsoon SPI-4 (e.g., up to -0.71 in WPH).
• During La Niña years, SOI showed the best positive linkages with monsoon SPI-4 (e.g., up to 0.59 in TGP and WDR).

Contributions

• Provides a comprehensive spatiotemporal analysis of meteorological drought trends across 14 Agro Climatic Zones of India using multiple advanced and traditional statistical methods (ITA, MK/m-MK, Sen’s slope, SLR).
• Offers a detailed examination of the teleconnections between monsoon season drought and major ocean-atmospheric indices (ENSO and IOD) over a long period (1903–2022) at the ACZ level, which was previously lacking.
• Highlights the superior capability of ITA in detecting significant trends compared to traditional methods, especially for hydro-climatic time series.
• Confirms ENSO as the dominant driver of drought variability in Indian ACZs and clarifies the marginal role of IOD in modulating long-term drought risk, providing valuable insights for drought prediction and agricultural/water resource planning.

Funding

No funding was received for conducting this study.

Citation

@article{Sah2026Spatiotemporal,
  author = {Sah, Sonam and Singh, RN and Das, B. and Mishra, Sudhir Kumar and Singh, Yogeshwar and Singh, AK and Reddy, K. Sammi},
  title = {Spatiotemporal analysis of drought and its teleconnections over agro climatic zones of India},
  journal = {Environmental Earth Sciences},
  year = {2026},
  doi = {10.1007/s12665-025-12791-3},
  url = {https://doi.org/10.1007/s12665-025-12791-3}
}