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<p>Climate change poses severe challenges to agriculture, water resources, infrastructure, and livelihoods, increasing the frequency of hydrological extremes at the basin level. The Ramganga basin, a vital water source for millions, is highly vulnerable to these events. This study assesses CMIP6 models’ ability to simulate precipitation- and temperature-related hydrological extremes over the basin. Using 34 years of observed data (1981–2014) and CMIP6 Shared Socioeconomic Pathways (SSP370) precipitation scenarios, the study assesses hydrological extremes for the mid-future (2041–2070). Bias correction was performed using the Quantile Mapping (QM) ensemble method on the four best-performing CMIP6 models. Trends across 51 grid points were assessed using the Mann–Kendall test and Sen’s slope, while droughts were characterized using the Standardized Precipitation Index (SPI) at multiple timescales and run theory. Findings highlight an increase in consecutive wet days (CWD) historically, shifting to a statistically non-significant (<i>p</i> &gt; 0.05) future trend. The PRCPTOT index indicates a statistically significant (<i>p</i> &lt; 0.05) 90% increase in precipitation in the historical period, transitioning to a non-significant 54% increase in the future, reflecting high variability. The spatial variability of extreme indices shows that, in the historical period (1981–2014), the northern and northeastern regions experienced (CWD &gt; 70 days), while the central and southern parts faced prolonged dry spells (CDD &gt; 30–45 days). In the future period (2041–2070), these patterns intensify, with CDD extending to &gt; 40–60 days in the central and southern sub-regions and CWD with same trend in northern and northeastern areas. Indices, R40mm (≥ 4–6 days) and Rx5day (&gt; 250&#xa0;mm) are concentrated in the eastern and central sub-regions in both periods, with higher number of stations in the future. The study advocates for watershed management plans incorporating resilient strategies to address future climate challenges, emphasizing effective water resource management to safeguard the basin’s future.</p>

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Intensifying hydroclimatic extremes and drought dynamics in Ramganga Basin (India): insights from CMIP6 SSP370 ensemble analysis

  • 期刊论文

  • 发表日期：

    2025年10月29日

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  • Naman Kumar Rajouria,
  • Aditya Sharma,
  • Devesh Sharma,
  • S. K. Panda

摘要

Climate change poses severe challenges to agriculture, water resources, infrastructure, and livelihoods, increasing the frequency of hydrological extremes at the basin level. The Ramganga basin, a vital water source for millions, is highly vulnerable to these events. This study assesses CMIP6 models’ ability to simulate precipitation- and temperature-related hydrological extremes over the basin. Using 34 years of observed data (1981–2014) and CMIP6 Shared Socioeconomic Pathways (SSP370) precipitation scenarios, the study assesses hydrological extremes for the mid-future (2041–2070). Bias correction was performed using the Quantile Mapping (QM) ensemble method on the four best-performing CMIP6 models. Trends across 51 grid points were assessed using the Mann–Kendall test and Sen’s slope, while droughts were characterized using the Standardized Precipitation Index (SPI) at multiple timescales and run theory. Findings highlight an increase in consecutive wet days (CWD) historically, shifting to a statistically non-significant (p > 0.05) future trend. The PRCPTOT index indicates a statistically significant (p < 0.05) 90% increase in precipitation in the historical period, transitioning to a non-significant 54% increase in the future, reflecting high variability. The spatial variability of extreme indices shows that, in the historical period (1981–2014), the northern and northeastern regions experienced (CWD > 70 days), while the central and southern parts faced prolonged dry spells (CDD > 30–45 days). In the future period (2041–2070), these patterns intensify, with CDD extending to > 40–60 days in the central and southern sub-regions and CWD with same trend in northern and northeastern areas. Indices, R40mm (≥ 4–6 days) and Rx5day (> 250 mm) are concentrated in the eastern and central sub-regions in both periods, with higher number of stations in the future. The study advocates for watershed management plans incorporating resilient strategies to address future climate challenges, emphasizing effective water resource management to safeguard the basin’s future.