Kumari et al. (2026) Spatio-temporal analysis of rainfall extremes and drought variability in the Tel basin, Odisha, India, under changing climate

Identification

• Journal: Innovative Infrastructure Solutions
• Year: 2026
• Date: 2026-02-09
• Authors: Pushpanjali Kumari, H. P. Singh, Pankaj Singh Dangi, Anoop Kumar Shukla
• DOI: 10.1007/s41062-026-02515-2

Research Groups

• Department of Civil Engineering, Central University of Jharkhand, Ranchi, India
• Water Resources, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh, India
• Manipal School of Architecture and Planning, Manipal Academy of Higher Education, Manipal, Karnataka, India

Short Summary

This study analyzed spatio-temporal rainfall trends, extreme climatic indices, and drought variability in India's Tel Basin (1981-2021), revealing increasing monsoon rainfall and heavy rainfall events, declining pre-monsoon rainfall and wet days, and an intensified drying trend driven by rising temperatures, highlighting the urgent need for adaptive water management.

Objective

• To analyze the spatial and temporal variations in rainfall trends, extreme climatic indices, and drought variability in the Tel Basin, Odisha, India, from 1981 to 2021, to assess the impacts of climate change on water resources and agricultural sustainability.

Study Configuration

• Spatial Scale: Tel Basin, Odisha, India, a major tributary of the Mahanadi River Basin. The study area is situated between longitude 82°04′E to 84°30′E and latitude 19°20′N to 20°40′N, covering an area of approximately 23,000 km².
• Temporal Scale: 40 years, from 1981 to 2021. Seasonal analysis included winter (January–February), pre-monsoon (March–May), monsoon (June–September), and post-monsoon (October–December).

Methodology and Data

• Models used:
  • Mann–Kendall (MK) test for assessing the significance of trends.
  • Sen’s slope estimator for quantifying the magnitude of trends.
  • Climpact software (R-based) for computing 9 selected extreme precipitation and temperature indices (e.g., R20mm, R30mm, SDII, CDD, CWD, PRCPTOT, TXm, SU, TXx).
  • Standardized Precipitation Index (SPI) for drought variability (3, 6, and 12-month scales).
  • Standardized Precipitation Evapotranspiration Index (SPEI) for drought variability (3, 6, and 12-month scales).
  • Inverse Distance Weighting (IDW) method for generating graphical maps in ArcGIS 10.3.
• Data sources:
  • Daily gridded rainfall data with a spatial resolution of 0.25° from the Indian Meteorological Department (IMD), Pune.
  • Daily gridded temperature data with a spatial resolution of 1.0° from the Indian Meteorological Department (IMD), Pune.

Main Results

• Rainfall Trends:
  • Pronounced spatial heterogeneity in rainfall trends across the Tel Basin.
  • Monsoon rainfall shows increasing trends in most regions, with Sen’s slope values up to 17.48 mm/decade.
  • Pre-monsoon rainfall exhibits a declining trend in most areas, with Sen’s slope values as low as −2.64 mm/decade.
  • Post-monsoon rainfall shows a slight increase (−0.33 to 1.79 mm/decade), while winter rainfall is mostly stable (−0.54 to 0.03 mm/decade).
• Extreme Rainfall Events:
  • Annual count of days with rainfall ≥ 20 mm (R20mm) and ≥ 30 mm (R30mm) shows increasing trends, implying more frequent heavy rain events and higher flood risks.
  • Consecutive dry days (CDD) have significantly increased by approximately 5 days/decade (Sen's slope = +1.3449), indicating longer dry spells and increased drought risks.
  • Consecutive wet days (CWD) have decreased by approximately 3 days/decade (Sen's slope = –0.1321), suggesting shorter wet periods.
  • Simple Daily Intensity Index (SDII) shows an increasing trend, indicating more intense rainfall on wet days.
  • Annual total precipitation on wet days (PRCPTOT) shows a variable but overall slight long-term increasing trend.
• Drought Variability:
  • SPI-6 exhibits a weak increasing trend (Sen’s slope = 0.001), suggesting a slight shift towards wetter conditions based solely on precipitation.
  • SPEI-6 indicates a stronger drying pattern (Sen’s slope = −0.005), highlighting that rising temperatures exacerbate drought conditions by increasing evapotranspiration.
• Temperature Extremes:
  • Annual mean value of daily maximum temperature (TXm) shows an upward trajectory, increasing from 31.5 °C to 32.5 °C, leading to higher evapotranspiration rates.
  • Maximum daily maximum temperature (TXx) has increased at a rate of approximately 0.02 °C per year, indicating rising extreme heat events.
  • The number of summer days (SU, TX > 25 °C) remains relatively stable, but the increasing TXm suggests existing warm days are becoming hotter.

Contributions

• Provides a comprehensive, region-specific analysis of climate change impacts on rainfall, temperature extremes, and drought variability in the Tel Basin, a critical agricultural region in India.
• Highlights the crucial divergence between precipitation-only (SPI) and temperature-adjusted (SPEI) drought assessments, underscoring the intensifying role of rising temperatures in regional drought severity.
• Offers detailed insights into seasonal rainfall imbalances (increasing monsoon, declining pre-monsoon), increased heavy rainfall events, and prolonged dry spells, which are vital for localized planning.
• Stresses the urgent need for adaptive water resource management, climate-resilient agricultural practices, and improved irrigation planning tailored to the Tel Basin's evolving climate conditions.
• Serves as a valuable reference for policymakers, water resource managers, and agricultural planners in formulating targeted adaptation and mitigation strategies for similar vulnerable regions.

Funding

Open access funding provided by Manipal Academy of Higher Education, Manipal. This research received no external funding.

Citation

@article{Kumari2026Spatiotemporal,
  author = {Kumari, Pushpanjali and Singh, H. P. and Dangi, Pankaj Singh and Shukla, Anoop Kumar},
  title = {Spatio-temporal analysis of rainfall extremes and drought variability in the Tel basin, Odisha, India, under changing climate},
  journal = {Innovative Infrastructure Solutions},
  year = {2026},
  doi = {10.1007/s41062-026-02515-2},
  url = {https://doi.org/10.1007/s41062-026-02515-2}
}