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<p>Drought, a pervasive natural disaster, poses significant threats to water resources, agriculture, and socioeconomic stability, with its intensity and frequency projected to increase under a changing climate. Rayalaseema in Andhra Pradesh, with its distinctive features of hilly terrain and semi-arid climate marked by the lowest rainfall in India and the influence of both southwest and northeast monsoons, is an ideal setting for drought research. Understanding long-term regional trends in rainfall and temperature is essential for formulating effective adaptation strategies in the context of global climate change. The current study examined the regional trend change of meteorological factors and drought indices to determine drought characteristics during the last 61&#xa0;years (1961–2021). Satellite-derived climate indicators, specifically the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI), were employed to analyze variations in drought patterns and assess climate change impacts. The Mann–Kendall trend test and Sen’s slope estimator were used to determine the importance of drought-related trends at different temporal and geographical scales. The findings show that the SPEI is more beneficial than the SPI for studying climate change and drought variability in Rayalaseema. The Rayalaseema climate has shifted significantly from dry to wet in recent decades. A strong positive Indian Ocean Dipole (IOD) is observed in September, followed by August, June, and July. Based on the SPI, extreme droughts occur approximately 6% of the time in the Kadapa and Anantapur districts. Similarly, the SPEI indicates that extreme droughts occur about 6% of the time in the Kurnool district. The analysis confirms that a positive IOD phase is associated with enhanced monsoon rainfall in the Rayalaseema region. Temperature shows a consistent negative correlation with SPI, SPEI, and rainfall, while rainfall exhibits a strong positive association with drought indices aligning with their respective formulations. These findings reinforce the applicability of known climatic relationships in the regional context. Continuous Wavelet Transform analysis of rainfall, temperature, SPI, and SPEI (1961–2021) in Rayalaseema reveals dominant 8–16&#xa0;month periodicities linked to the Indian Summer Monsoon, with additional 2–8 and 16–32&#xa0;month variability influenced by Madden–Julian Oscillation, IOD, and El Niño-Southern Oscillation, underscoring spatial heterogeneity and the need for localized climate risk strategies.</p>

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Decadal analysis of monsoon climate variability and drought indicators in Rayalaseema: long-term analysis using satellite data and drought indices

  • 期刊论文

  • 发表日期：

    2025年8月2日

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  • Kandula Bharghavi,
  • Thotli Lokeswara Reddy,
  • Hemalatha Kapa,
  • Penti Rajesh,
  • Hasanapuram Sushmitha,
  • Krishnareddigari Krishna Reddy

摘要

Drought, a pervasive natural disaster, poses significant threats to water resources, agriculture, and socioeconomic stability, with its intensity and frequency projected to increase under a changing climate. Rayalaseema in Andhra Pradesh, with its distinctive features of hilly terrain and semi-arid climate marked by the lowest rainfall in India and the influence of both southwest and northeast monsoons, is an ideal setting for drought research. Understanding long-term regional trends in rainfall and temperature is essential for formulating effective adaptation strategies in the context of global climate change. The current study examined the regional trend change of meteorological factors and drought indices to determine drought characteristics during the last 61 years (1961–2021). Satellite-derived climate indicators, specifically the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI), were employed to analyze variations in drought patterns and assess climate change impacts. The Mann–Kendall trend test and Sen’s slope estimator were used to determine the importance of drought-related trends at different temporal and geographical scales. The findings show that the SPEI is more beneficial than the SPI for studying climate change and drought variability in Rayalaseema. The Rayalaseema climate has shifted significantly from dry to wet in recent decades. A strong positive Indian Ocean Dipole (IOD) is observed in September, followed by August, June, and July. Based on the SPI, extreme droughts occur approximately 6% of the time in the Kadapa and Anantapur districts. Similarly, the SPEI indicates that extreme droughts occur about 6% of the time in the Kurnool district. The analysis confirms that a positive IOD phase is associated with enhanced monsoon rainfall in the Rayalaseema region. Temperature shows a consistent negative correlation with SPI, SPEI, and rainfall, while rainfall exhibits a strong positive association with drought indices aligning with their respective formulations. These findings reinforce the applicability of known climatic relationships in the regional context. Continuous Wavelet Transform analysis of rainfall, temperature, SPI, and SPEI (1961–2021) in Rayalaseema reveals dominant 8–16 month periodicities linked to the Indian Summer Monsoon, with additional 2–8 and 16–32 month variability influenced by Madden–Julian Oscillation, IOD, and El Niño-Southern Oscillation, underscoring spatial heterogeneity and the need for localized climate risk strategies.