Contrasting changes in the sea surface temperature and upper ocean heat content in the South China Sea during recent decades
Contrasting changes in the sea surface temperature and upper ocean heat content in the South China Sea during recent decades
复制标题
近几十年来南海海面温度与上层海洋热含量变化对比
DOI：
10.1007/s00382-019-04697-1
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发表时间：
2019
期刊：
影响因子：
4.6
通讯作者：
Zhou Wen
中科院分区：
文献类型：
--
作者：
Xiao Fuan;Wang Dongxiao;Zeng Lili;Liu Qin-Yan;Zhou Wen
了解海洋上层热条件的变化是区域气候预测的关键。近几十年来，南海海表温度和上层海洋热含量（SCS SST和SCS OHC）呈现出明显的对比变化。现场观测和再分析资料显示，1975-2010年南海SST呈线性增暖趋势，但20世纪90年代后期南海OHC发生了体制转换。混合层热量收支分析表明，南海海温的增暖趋势与潜热通量的减少和地面风的减弱有关。南海SST的增加反映了全球变暖的区域足迹。一个简化的上层预算诊断表明，超过一半的OHC变化的结果来自平流效应，这是由一个异常的南海反气旋环流与异常的负风应力旋度。异常反气旋环流加深了海盆尺度的温跃层深度，导致南海OHC的体制转换。海洋环流的变化被认为是与增强的信风和松野-吉尔响应冷却在热带中太平洋。进一步的分析表明，该区域的体制转换过程是年代际太平洋涛动（IPO）由正向负的相变过程。结果表明，虽然IPO是海表低频气候型，但它可以通过海洋过程影响南海次表层热变率。
Understanding the variability of upper ocean thermal conditions is key to regional climate prediction. In recent decades, the sea surface temperature and upper ocean heat content in the South China Sea (SCS SST and SCS OHC) have exhibited contrasting changes. In-situ observations and reanalysis data reveal a linear warming trend in SCS SST during 1975–2010 but a regime shift of SCS OHC during the late 1990s. Mixed layer heat budget analysis shows that the decreasing latent heat flux associated with a weakening surface wind contributes to SCS SST warming trend. The increasing SCS SST reflects a regional footprint of global warming. A simplified upper layer budget diagnosis reveals that more than half of OHC change results from the advection effect, which is caused by an anomalous SCS anticyclonic gyre associated with an anomalous negative wind stress curl. Then, the anomalous anticyclonic circulation deepens thermocline depth at the basin-scale, and result in the regime shift of SCS OHC. Changes in the ocean circulation are found to be related to the enhanced trade wind and a Matsuno-Gill response to cooling in the tropical central Pacific. Further analyses show that the regime shift process is attributed to a phase transition of the Interdecadal Pacific Oscillation (IPO) from positive to negative. Our results indicate that although the IPO is the sea surface low-frequency climate pattern, it could impact on the subsurface thermal variability in the SCS through the oceanic process.