Onset of the regional monsoon over Southeast Asia
Onset of the regional monsoon over Southeast Asia
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DOI：
10.1007/s007030070013
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发表时间：
2000-11
影响因子：
2
通讯作者：
W. Qian;Song Yang
中科院分区：
文献类型：
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作者：
W. Qian;Song Yang
这是一项观测研究，研究了亚洲特别是南中国海（SCS）不同夏季风分量的区域特征。作者利用包括卫星测量在内的各种数据集来了解季风的开始、维持和消退，并解释季风各分量变率之间的联系和独立性。结果表明，虽然外发长波辐射（OLR）数据只能测量热带对流，但对流层上层水汽带亮度温度（BT）在热带和温带都能很好地反映对流降水。作者定义了使用降水、BT、OLR和对流层低层风来测量南海季风的标准，并建议应该考虑多变量来充分描述区域季风特征。在本研究定义的标准下，南海夏季风被认为是来自热带的深层对流的扩张。季风在五月中旬开始，在印度支那半岛发现了它的前兆信号。它的特点是突然建立，特别是在南海中部。虽然南海南部对流在季风发生中的作用尚不清楚，但由于副热带锋的影响，南海北部和华南地区的早期降水与热带季风降水是分离的。一个季风分量相对于另一个季风分量的相对独立性可以用当地地形和海陆热对比的影响来解释。
¶This is an observational study in which regional features of the different summer monsoon components over Asia especially the South China Sea (SCS) are examined. The authors use various data sets including satellite measurements to understand the onset, maintenance, and retreat of monsoon and explain the connection and independence among the variabilities in the monsoon components. It is shown that while outgoing longwave radiation (OLR) data can only measure tropical convection, upper-tropospheric water vapor band brightness temperature (BT) represents appropriately convective precipitation in both the tropics and the extratropics. The authors define criteria for measuring the SCS monsoon using precipitation, BT, OLR, and lower-tropospheric winds and suggest that multi-variables should be considered to depict regional monsoon features adequately.Under the criteria defined in this study, the SCS summer monsoon is considered as an expansion of deep convection from the tropics. The onset of the monsoon occurs in mid-May, with its precursory signal found over the Indochina peninsula. It is characterized by an abrupt establishment, especially over the central SCS. Although the role of convection over the southern SCS in the monsoon onset is unclear, the early precipitation over the northern SCS and South China, resulted from the effect of subtropical fronts, is separated from the tropical monsoon rainfall. The relative independence from one monsoon component to another is explained by the effects from local topography and land-sea thermal contrast.