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<p>The increasing frequency and severity of compound extreme events, exacerbated by climate change, pose serious implications across various societal sectors. Effective mitigation strategies necessitate a thorough understanding of the spatiotemporal analysis of the compound extreme events, which cannot be adequately captured through single-index assessments. To address this limitation, the present study introduces a Standardized Agrometeorological Drought and Hot Index (SADHI) to analyze Compound Agrometeorological Drought and Hot Events (CADHE) in Kerala from 1955 to 2020. SADHI is a novel index developed by standardizing the joint distribution of the Standardized Precipitation Index (SPI), Standardized Soil moisture Index (SSI), and Standardized Temperature Index (STI) derived from a vine copula framework. The D-vine copula provides the best fit for the joint distribution of meteorological drought, agricultural drought, and hot events, with the lowest Akaike Information Criteria (AIC) (–&#xa0;292.12 to –&#xa0;555.51) and Bayesian Information Criteria (BIC) (-278.1 to -541.48) values, and the resulting SADHI reveals a marked increase in the frequency of CADHE after the year 1980, with extreme events notably occurring in the years 1983, 1988, 2002, 2012, 2016, and 2019. Among these, the 2016 event stands out as the most widespread and severe, with all grid points across Kerala exhibiting a SADHI value less than − 2. Furthermore, modified Mann-Kendall trend analysis indicates a significant decreasing trend in SADHI values, confirming the increasing severity of CADHE in Kerala. The joint return period analysis of CADHE characteristics indicates that the southern parts of the state consistently experience shorter return periods across all exceedance scenarios, underscoring high vulnerability, with 50th percentile return periods of less than 2.5 years and 75th percentile return periods ranging from 3 to 4.5 years. The developed index performs well in capturing CADHE and can therefore be used as an early warning indicator to support agricultural planning and drought management.</p>

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Evaluation of compound agrometeorological drought and hot events using a copula-based standardized index

  • 期刊论文

  • 发表日期：

    2026年2月16日

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  • Sruthi D. Sivan,
  • S. K. Pramada

摘要

The increasing frequency and severity of compound extreme events, exacerbated by climate change, pose serious implications across various societal sectors. Effective mitigation strategies necessitate a thorough understanding of the spatiotemporal analysis of the compound extreme events, which cannot be adequately captured through single-index assessments. To address this limitation, the present study introduces a Standardized Agrometeorological Drought and Hot Index (SADHI) to analyze Compound Agrometeorological Drought and Hot Events (CADHE) in Kerala from 1955 to 2020. SADHI is a novel index developed by standardizing the joint distribution of the Standardized Precipitation Index (SPI), Standardized Soil moisture Index (SSI), and Standardized Temperature Index (STI) derived from a vine copula framework. The D-vine copula provides the best fit for the joint distribution of meteorological drought, agricultural drought, and hot events, with the lowest Akaike Information Criteria (AIC) (– 292.12 to – 555.51) and Bayesian Information Criteria (BIC) (-278.1 to -541.48) values, and the resulting SADHI reveals a marked increase in the frequency of CADHE after the year 1980, with extreme events notably occurring in the years 1983, 1988, 2002, 2012, 2016, and 2019. Among these, the 2016 event stands out as the most widespread and severe, with all grid points across Kerala exhibiting a SADHI value less than − 2. Furthermore, modified Mann-Kendall trend analysis indicates a significant decreasing trend in SADHI values, confirming the increasing severity of CADHE in Kerala. The joint return period analysis of CADHE characteristics indicates that the southern parts of the state consistently experience shorter return periods across all exceedance scenarios, underscoring high vulnerability, with 50th percentile return periods of less than 2.5 years and 75th percentile return periods ranging from 3 to 4.5 years. The developed index performs well in capturing CADHE and can therefore be used as an early warning indicator to support agricultural planning and drought management.