Scholarlink

<p>This study examines projected changes in semi-permanent systems and their influence on Indian Summer Monsoon Rainfall (ISMR) for near-future (NF; 2031–2060) and far-future (FF; 2071–2100) periods using eight CMIP6 models under SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios. ACCESS-CM2 and CanESM5-CanOE models showed poor performance compared to others, hence the remaining six models are used in multi-model mean (MMM). Projections indicate a progressive weakening of the Low-Level Jet (−&#xa0;0.78% (-1&#xa0;ms<sup>−1</sup>) in NF to -2.98% (−&#xa0;1.2&#xa0;ms<sup>−1</sup>) in FF) and the upper-level Tropical Easterly Jet (-4.69% (~ −&#xa0;1&#xa0;m&#xa0;s<sup>−1</sup>) in NF to -11.7% (~ −&#xa0;3&#xa0;m&#xa0;s<sup>−1</sup>) in FF). In contrast, the Subtropical Westerly Jet exhibits a southward shift of ~ 1.5° in the FF, while the Tibetan Anticyclone strengthens (by 1–2%). Teleconnection reveals a persistent negative ENSO-ISMR relationship, with amplified influences from the Indian Ocean Dipole and North Atlantic Oscillation under SSP5-8.5 scenario. These circulation changes led to weakening of meridional shear (~ −&#xa0;1-2&#xa0;m&#xa0;s<sup>−1</sup>) and strengthening of zonal shear (~ 2–3&#xa0;m&#xa0;s⁻<sup>1</sup>) across the tropics. ISMR increases across all scenarios from NF to FF (~ 6–8% in SSP1-2.6, ~ 5–11% in SSP2-4.5, and ~ 6–17% in SSP5-8.5) despite a weakening of monsoon circulation. This increase is linked to more frequent rainfall events (&gt; 4&#xa0;mm&#xa0;day<sup>−1</sup>), especially over Central and Northwest India, along with an increased contribution from September, suggesting a delayed withdrawal and extended longer monsoon season. Overall, this reflects a transition toward thermodynamically driven rainfall intensification under warming.</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

Future changes in semi-permanent systems and seasonal rainfall during Indian summer monsoon: Insights from CMIP6 coupled models

  • 期刊论文

  • 发表日期：

    2026年6月22日

查看全文
  • G. Sripathi,
  • K. K. Osuri,
  • K. Koteswara Rao,
  • A. P. Dimri,
  • A. S. Rao

摘要

This study examines projected changes in semi-permanent systems and their influence on Indian Summer Monsoon Rainfall (ISMR) for near-future (NF; 2031–2060) and far-future (FF; 2071–2100) periods using eight CMIP6 models under SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios. ACCESS-CM2 and CanESM5-CanOE models showed poor performance compared to others, hence the remaining six models are used in multi-model mean (MMM). Projections indicate a progressive weakening of the Low-Level Jet (− 0.78% (-1 ms−1) in NF to -2.98% (− 1.2 ms−1) in FF) and the upper-level Tropical Easterly Jet (-4.69% (~ − 1 m s−1) in NF to -11.7% (~ − 3 m s−1) in FF). In contrast, the Subtropical Westerly Jet exhibits a southward shift of ~ 1.5° in the FF, while the Tibetan Anticyclone strengthens (by 1–2%). Teleconnection reveals a persistent negative ENSO-ISMR relationship, with amplified influences from the Indian Ocean Dipole and North Atlantic Oscillation under SSP5-8.5 scenario. These circulation changes led to weakening of meridional shear (~ − 1-2 m s−1) and strengthening of zonal shear (~ 2–3 m s⁻1) across the tropics. ISMR increases across all scenarios from NF to FF (~ 6–8% in SSP1-2.6, ~ 5–11% in SSP2-4.5, and ~ 6–17% in SSP5-8.5) despite a weakening of monsoon circulation. This increase is linked to more frequent rainfall events (> 4 mm day−1), especially over Central and Northwest India, along with an increased contribution from September, suggesting a delayed withdrawal and extended longer monsoon season. Overall, this reflects a transition toward thermodynamically driven rainfall intensification under warming.