1998年南海夏季风环流与动能 收支的多尺度特征

利用1998年NCEP/NCAR日平均资料研究南海夏季风环流及动能收支的多尺度变化。 结果表明1998年南海夏季风环流在对流层高层以季节变化为主，在低空以季节内变化为主；但在整个对流层，动能收支各项的变化均表现为短周期变化过程较强，而季节变化则较弱。在夏季风爆发前后，动能收支主要取决于120d和30～60d变化，爆发阶段突出了准两周与天气尺度变化的重要作用。

Multi-Time Scale Characteristics of Circulation and Kinetic Energy Budget During the South China Sea Summer Monsoon in 1998

Using NCEP/NCAR reanalysis daily data, the features of multi-time scale variations of circulation and kinetic energy budget during the South China Sea (SCS) summer monsoon in 1998 are studied. The results are as follows: (1)The variations on 120d time scales are dominant in the high-level circulation anomalies, and the variations on 30-60d and quasi-two weeks (QTW) time scales are dominant in the low-level circulation anomalies. However, it is shown that the short period process variance is stronger than the long one (120d) as far as the terms of kinetic energy budget are concerned. (2) Before the summer monsoon onset, the energy variation appears mainly above 300hPa, and the kinetic energy budget is determined by variations on 30-60d and 120d time scales. During the summer monsoon onset, both QTW and synoptic scale variation (SYN) play an important role in the generation of kinetic energy. After the monsoon onset, the energy decreases and its variances appear mainly below 300hPa. (3) The QTW oscillation and SYN variance are significant to the SCS summer monsoon onset.