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Abstract:
By using 40-year NCEP reanalysis daily data (1958-1997), we have analyzed the climatic characteristics of summer monsoon onset in the South China Sea (105°E ~ 120°E, 5°N ~ 20°N, to be simplified as SCS in the text followed) pentad by pentad (5 days). According to our new definition, in the monsoon area of the SCS two of the following conditions should be satisfied: 1) At 850hPa, the southwest winds should be greater than 2m/s. 2) At 850 hPa, θse should be greater than 335°K. The new definition means that the summer monsoon is the southwest winds with high temperature and high moisture. The onset of the SCS summer monsoon is defined to start when one half of the SCS area (105°E ~ 120°E,5°N ~ 20°N) is controlled by the summer monsoon. The analyzed results revealed the following: 1) The summer monsoon in the SCS starts to build up abruptly in the 4th pentad in May. 2) The summer monsoon onset in the SCS is resulted from the development and intensification of southwesterly monsoon in the Bay of Bengal. 3) The onset of the summer monsoon and establishment of the summer monsoon rainfall season in the SCS occur simultaneously. 4) During the summer monsoon onset in the SCS, troughs deepen and widen quickly in the lower troposphere of the India; the subtropical high in the Western Pacific moves eastward off the SCS in the middle troposphere; the easterly advances northward over the SCS in the upper troposphere.
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References
[1]
|
LI Chong-yin, QU Xin. Characteristics of Atmospheric Circulation with Summer Monsoon Onset in the SouthChins Sea, Onset and Evolution of the South China Sea Monsoon and Its Interaction with the Ocean [M].Beijing: China Meteorological Press, 1998. 5-12. |
[2]
|
LIU Xia, XIE An, YE Qian, et al. The climatic characteristics of summer monsoon onset over South China Sea[J]. Journal of Tropical Meteorology, 1998, 14 (1): 28-46. |
[3]
|
LUO Hui-bang. An analysis study on the onset of the South China Sea summer monsoon in 1998 [A]. Onsetand evolution of the South China Sea monsoon and its interaction with the ocean [M]. Beijing: ChinaMeteorological Press, 1999. 25-29. |
[4]
|
JIN Zu-hui. An analysis study on the South China Sea summer monsoon in 1998 [A]. Onset and evolution ofthe South China Sea monsoon and its interaction with the ocean [C]. China Meteorological Press, 1999. 57-65. |
[5]
|
WU Guo-xiong, ZHANG Yong-sheng. The thermal and mechanical forcing of the Tibetan Plateau and theAsian monsoon onset, I situating of the onset [J]. Chinese Journal of Atmospheric Sciences (formerly ScientiaAtmospherica Sinica), 1998, 22(6): 825-838. |
[6]
|
CHEN Long-xun, ZHU Cong-wen. Characteristics and mechanism analysis of SCS summer monsoon onsetduring SCSMEX in 1998[M]. Beijing: China Meteorological Press, 1999. 13-17. |
[7]
|
LAU K M, YANG S, Climatology and interannual variability of the southeast Asia summer monsoon [J].Advances in Atmospheric Sciences, 1997, 14: 141-161. |
[8]
|
FONG Soi-kun, WANG An-yu, WU Chi-sheng, et al. The definition of the advance and retreat of summermonsoon in eastern china [J]. Plateau Meteorology, 1999, 18 (3): 400-408. |
[9]
|
ZHANG Yong-sheng, WU Guo-xiong. A study on the dynamic mechanism of the onset of Asian summermonsoon and abrupt change of atmospheric circulation in the Northern Hemisphere:ⅡThe role of sensibleheating on the surface in the Tibetan Plateau and its neighboring region [J]. Acta Meteorologica Sinica, 1999,13 (1): 56-72. |
[10]
|
WANG An-yu, GU Hong-dao,WANG Qian-qian, et al. The numerical experiment on the effect of the meanfield of atmospheric circulation by the heating field of the East Asian region in the beginning of summer [A].Proceeding of the meteorological scientific experiment over the Tibetan Plateau (2) [C]. Beijing: China SciencePress, 1984. 273-280. |
[11]
|
ZHU Fu-kang,LU Long-hua, CHEN Wei-ji, et al. South Asian High [M]. Beijing: China Science Press, 1980.95. |
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