Characteristics of the South China Sea Monsoon from the Onset to Withdrawal before and after 1993/94
Characteristics of the South China Sea Monsoon from the Onset to Withdrawal before and after 1993/94
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DOI：
10.1155/2020/8820460
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发表时间：
2020-09
影响因子：
2.9
通讯作者：
Zhao Xiaofang;W. Lijuan
中科院分区：
文献类型：
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作者：
Zhao Xiaofang;W. Lijuan
利用ERA-Interim、CPC降水和OLR资料，分析了1993/94年前后南海夏季风（SCSSM）从爆发到消退的演变特征及其可能的影响因素。1979-1993年爆发后期，南海夏季风爆发强度较强，但逐渐消退，导致华南前汛期持续较强，9月雨带由北向南消退较慢。此外，长江流域的雨带在夏季持续时间更长。然而，在1994-2016年的早发期，SCSSM与较弱的发病强度和相对较快的撤退。前汛期的提前在整个5月间歇性地持续，整个华东地区的降水持续到10月后迅速消退，使华南雨带持续时间延长。进一步的分析表明，南海季节内振荡（ISO）对南海夏季风的演变有很强的调制作用。夏季南海有两个活跃的低频振荡在晚发期，但在早发期有三个。1993/94年以后，西北太平洋的湿ISO向西北方向传播到南海，SCSSM ISO活动增强，这可能是造成南海ISO爆发早、消退快的原因。本文还讨论了西太平洋暖海温对南海夏季风演变的影响。
The characteristics and possible impact factors of the South China Sea summer monsoon (SCSSM) evolution from onset to withdrawal before and after 1993/94 are investigated using ERA-Interim, CPC rainfall, and OLR data. During the late-onset period of 1979–1993, the SCSSM was characterized by stronger onset intensity and a gradual withdrawal, resulting in a continuous, strong preflood season in Southern China and a slower rain-belt retreat from north to south China in September. In addition, the rain-belt in the Yangtze River basin persisted much longer during summer. However, during the early-onset period in 1994–2016, the SCSSM is associated with a weaker onset intensity and comparatively faster retreat. The advanced preflood season lasted intermittently throughout May and the whole eastern China precipitation lasted until October when it retreated rapidly, making the rain-belt in Southern China persist for an extended duration. Further analysis indicates that a strong modulation of SCS intraseasonal oscillation (ISO) on the SCSSM evolution is observed. There are two active low-frequency oscillations over the SCS in summer during the late-onset period but three during the early-onset period. The wet ISO in the Northwest Pacific propagating northwestward into the SCS and enhanced SCSSM ISO activity may contribute to the early onset and faster withdrawal after 1993/94. The effect of warm western Pacific sea surface temperatures (SST) on the SCSSM evolution is also discussed.