Scholarlink

<p>Understanding historical variations in sub-daily rainfall extremes is critical for anticipating their future evolution under changing climate conditions. Using long-term hourly rainfall records from Meenambakkam, Chennai (1969–2023), this study investigates the behavior and evolving trends of short duration (1–3&#xa0;h) rainfall extremes. Although total annual and seasonal rainfall exhibited no pronounced long-term trend, notable shifts were detected in rainfall intensity, frequency, and duration. During the region’s dominant rainfall season, the northeast monsoon (NEM), the rainfall centroid shifted later by approximately 5.9&#xa0;days, suggesting a delayed seasonal concentration. About 90% of the NEM rainfall (mean = 735.37&#xa0;mm) occurred within just 4.6&#xa0;days, revealing a markedly concentrated rainfall regime. Remarkably, 53.03% of daily rainfall occurred within a single hour, underscoring the dominance of intense, short-lived events. Extreme rainfall during the NEM increasingly occurs during afternoon-night hours and has become more variable over time, with higher short-duration intensities observed in the recent decades. Transition probability analysis revealed that a one-hour rainfall extreme had a 0.732 likelihood of persisting to three hours, but only a 0.482 likelihood of extending to six hours, reinforcing the short-lived yet severe character of the NEM storms. Event frequencies of intense 1–3&#xa0;h rainfall have also risen, signaling a strengthening of sub-daily extremes. Moreover, the monsoon extension beyond December into January has become increasingly evident in the past decade (2015–2023), with mean daily rainfall nearly doubling to 36.82&#xa0;mm and the maximum recorded intensity surging from 86.80 to 216&#xa0;mm. Collectively, these findings highlight a transition toward more intense, temporally concentrated, and variable rainfall extremes, underscoring the growing need for enhanced localized flood forecasting, improved drainage design, and robust&#xa0;urban resilience strategies.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Evolving patterns of hourly rainfall extremes across seasonal regimes in Chennai, India

  • 期刊论文

  • 发表日期：

    2026年2月12日

查看全文
  • Praveenbalaji Bheeman,
  • Sathyanathan Rangarajan

摘要

Understanding historical variations in sub-daily rainfall extremes is critical for anticipating their future evolution under changing climate conditions. Using long-term hourly rainfall records from Meenambakkam, Chennai (1969–2023), this study investigates the behavior and evolving trends of short duration (1–3 h) rainfall extremes. Although total annual and seasonal rainfall exhibited no pronounced long-term trend, notable shifts were detected in rainfall intensity, frequency, and duration. During the region’s dominant rainfall season, the northeast monsoon (NEM), the rainfall centroid shifted later by approximately 5.9 days, suggesting a delayed seasonal concentration. About 90% of the NEM rainfall (mean = 735.37 mm) occurred within just 4.6 days, revealing a markedly concentrated rainfall regime. Remarkably, 53.03% of daily rainfall occurred within a single hour, underscoring the dominance of intense, short-lived events. Extreme rainfall during the NEM increasingly occurs during afternoon-night hours and has become more variable over time, with higher short-duration intensities observed in the recent decades. Transition probability analysis revealed that a one-hour rainfall extreme had a 0.732 likelihood of persisting to three hours, but only a 0.482 likelihood of extending to six hours, reinforcing the short-lived yet severe character of the NEM storms. Event frequencies of intense 1–3 h rainfall have also risen, signaling a strengthening of sub-daily extremes. Moreover, the monsoon extension beyond December into January has become increasingly evident in the past decade (2015–2023), with mean daily rainfall nearly doubling to 36.82 mm and the maximum recorded intensity surging from 86.80 to 216 mm. Collectively, these findings highlight a transition toward more intense, temporally concentrated, and variable rainfall extremes, underscoring the growing need for enhanced localized flood forecasting, improved drainage design, and robust urban resilience strategies.