Scholarlink

<p>The South China Sea (SCS) summer monsoon (SCSSM) onset marks the beginning of the East Asian summer monsoon and has large effects on the weather and climate variations in East Asia. The onset date of the SCSSM exhibits prominent interannual variability, which has traditionally been ascribed to El Niño–Southern Oscillation (ENSO). However, the relationship between ENSO and the SCSSM onset has been found to have significantly weakened over the most recent two decades. Compared to the tropical factors, signals from the middle and high latitudes receive much less attention. In this study, we reveal that North Atlantic (NA) sea surface temperature (NASST) has emerged as a significant modulator of the SCSSM onset since the early 2000s. Positive anomalous NASST in May that persisted from the preceding months can trigger an eastward-propagating Rossby wave train, leading to a quasi-barotropic cyclonic anomaly over East Asia. The northerly anomalies at the western side of the cyclone transport cold air southward in eastern China, inducing significant cooling over the north of the SCS. As a result, negative meridional temperature gradient appears over the SCS, meanwhile arousing anomalous warm advection under the climatological southerlies in the lower troposphere. This warm advection triggers the upward motions and convection over the SCS, finally prompting the SCSSM onset. The aforesaid physical mechanism responsible for NASST anomalies affecting the SCSSM onset is well verified by numerical simulations. Our findings raise the intriguing possibility that the extratropical NASST anomalies can provide additional seasonal predictability of the SCSSM onset date.</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 enhanced relationship between North Atlantic SST and South China Sea summer monsoon onset since the early 2000s

  • 期刊论文

  • 发表日期：

    2025年11月3日

查看全文
  • Pengyou Lai,
  • Ziqian Wang,
  • Haoyuan Shi,
  • Minling Ke,
  • Yamin Hu

摘要

The South China Sea (SCS) summer monsoon (SCSSM) onset marks the beginning of the East Asian summer monsoon and has large effects on the weather and climate variations in East Asia. The onset date of the SCSSM exhibits prominent interannual variability, which has traditionally been ascribed to El Niño–Southern Oscillation (ENSO). However, the relationship between ENSO and the SCSSM onset has been found to have significantly weakened over the most recent two decades. Compared to the tropical factors, signals from the middle and high latitudes receive much less attention. In this study, we reveal that North Atlantic (NA) sea surface temperature (NASST) has emerged as a significant modulator of the SCSSM onset since the early 2000s. Positive anomalous NASST in May that persisted from the preceding months can trigger an eastward-propagating Rossby wave train, leading to a quasi-barotropic cyclonic anomaly over East Asia. The northerly anomalies at the western side of the cyclone transport cold air southward in eastern China, inducing significant cooling over the north of the SCS. As a result, negative meridional temperature gradient appears over the SCS, meanwhile arousing anomalous warm advection under the climatological southerlies in the lower troposphere. This warm advection triggers the upward motions and convection over the SCS, finally prompting the SCSSM onset. The aforesaid physical mechanism responsible for NASST anomalies affecting the SCSSM onset is well verified by numerical simulations. Our findings raise the intriguing possibility that the extratropical NASST anomalies can provide additional seasonal predictability of the SCSSM onset date.