Scholarlink

<p>The Indian summer monsoon (ISM) is strongly influenced by the El Niño-Southern Oscillation (ENSO), with Central Pacific (CP) El Niño events typically producing more severe droughts over India than Eastern Pacific (EP) events. Using idealized atmospheric model experiments, we show that this contrasting response is governed by sea surface temperature (SST) anomalies in the south-eastern Indian Ocean (SEIO). Under Pacific-only SST forcing, EP El Niño suppresses ISM rainfall more strongly than CP El Niño events. The addition of SEIO cooling reverses this hierarchy, with enhanced drying over India during CP events relative to EP events. The reversal arises because the zonal separation between the warm Pacific and the cold anomalies around the Maritime Continent (MC) is greater during EP events, forcing Walker descent over the MC, whereas the separation is less during CP events, allowing subsidence to spread over India. Diagnostics confirm that the combined response is strongly nonlinear. These results advance our mechanistic understanding of how the spatial configuration of SST anomalies across the Indo-Pacific governs the Indian summer monsoon response to El Niño, with implications for how ENSO-type diversity is represented in prediction systems.</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

The influence of cold SST anomalies surrounding the Maritime Continent on the El Niño-Indian monsoon teleconnection

  • 期刊论文

  • 发表日期：

    2026年7月28日

查看全文
  • Uppara Umakanth,
  • Benjamin Webber,
  • Manoj Joshi,
  • Andrew Turner

摘要

The Indian summer monsoon (ISM) is strongly influenced by the El Niño-Southern Oscillation (ENSO), with Central Pacific (CP) El Niño events typically producing more severe droughts over India than Eastern Pacific (EP) events. Using idealized atmospheric model experiments, we show that this contrasting response is governed by sea surface temperature (SST) anomalies in the south-eastern Indian Ocean (SEIO). Under Pacific-only SST forcing, EP El Niño suppresses ISM rainfall more strongly than CP El Niño events. The addition of SEIO cooling reverses this hierarchy, with enhanced drying over India during CP events relative to EP events. The reversal arises because the zonal separation between the warm Pacific and the cold anomalies around the Maritime Continent (MC) is greater during EP events, forcing Walker descent over the MC, whereas the separation is less during CP events, allowing subsidence to spread over India. Diagnostics confirm that the combined response is strongly nonlinear. These results advance our mechanistic understanding of how the spatial configuration of SST anomalies across the Indo-Pacific governs the Indian summer monsoon response to El Niño, with implications for how ENSO-type diversity is represented in prediction systems.