摘要
利用ＮＣＥＰ再分析及ＴＢＢ资料，系统地研究了１９９８年南海夏季风爆发与大气季节内振荡活动的关系，结果表明，１９９８年南海夏季风爆发与南海及其临近地区３０～６０天低频振荡的发展有着极为密切的关系。南海及临近地区３０～６０天低频纬向风及低频动能的时间－经（纬）度剖面明显地反映出该地区的大气季节内振荡的加强是由于其临近地区（菲律宾以东）３０～６０天低频气旋发展及其向西扩展的结果，与孟加拉湾地区低频气旋的活动关系不大；同时，我们也看到了夏季风爆发前后南海地区为 ８５０ｈＰａ低频动能的大值区，而 ２００ｈＰａ上为一弱区，反映了１９９８年南海夏季风爆发期间该地区大气季节内振荡有上弱下强的垂直分布特征。进一步分析表明，南海及其临近地区大气季节内振荡的活动主要为局地振荡型，夏季风爆发后才有明显的向北传播，成为南海夏季风爆发影响东亚大气环流和天气的重要途径之一。另外，１９８０和１９８６年南海地区３０～６０天低频动能的发展特征与 １９９８年的类似，说明了南海及其临近地区大气季节内振荡的局地振荡特征并不是１９９８年所特有的，它对南海夏季风爆发有普遍的重要作用。
The relationship between outbreak of the South China Sea Summer Monsoon in 1998 and the activity of atmospheric intraseasonal oscillation is systemically studied by using NCEP re-analysis and TBB (Temperature of Black Body) data. The results show that outbreak of the South China Sea Summer Monsoon in 1998 is closely related to the developing of 30-60 days low-frequency oscillation in the South China Sea and its nearby. The time-longitude (latitude) cross-sections of the 30-60 days low-frequency zonal wind and kinetic energy in the South China Sea and its nearby obviously reflect that the increasing of atmospheric intraseasonal oscillation is excited by the developing of the 30-60 days low-frequency cyclone over the Philippines area and its expanding westwards. There is no clear as- sociation with the low-frequency cyclone activity over the Bay of Bengal. Meanwhile, near to outbreak of the South China Sea Summer Monsoon, the low-frequency kinetics at 850 hPa over the South China Sea is much stronger than that of its nearby, but it is much weaker at 200 hPa. This reflects the weak to strong vertical structure feature from the lower to upper troposphere. The further analyses show the local activity characteristics of the atmospheric intraseasonal oscillation over the South China Sea and its nearby. However, after the monsoon outbreak, the low-frequency oscillation begins to propagate northwards and become the important pass to influence the weather and climate in East Asia. Additionally, the developing characteristics of the 30-60 days kinetic over the South China Sea in 1980 and 1986 are very similar to that of 1998. It represents that the local activity feature of the atmospheric intra-seasonal oscillation over the South China Sea and its nearby is not only in 1998, and has the common effect on the outbreak of the South China Sea Summer Monsoon.
出处
《气候与环境研究》
CSCD
2000年第4期375-387,共13页
Climatic and Environmental Research
基金
国家科技部攀登项目A"南海季风试验研究"
中国科学院!KZ951-B1-408
中国科学院大气物理研究所创新基金8-1303
