利用大尺度环流确定2006年南海夏季风爆发日期

DETERMINATION OF THE ONSET DATE OF THE SOUTH CHINA SEA SUMMER MONSOON IN 2006 FROM LARGE-SCALE CIRCULATIONS

南海夏季风爆发最显著的特征就是南海地区西南风的突然增强和降水的明显增多,往往采用南海地区低层平均风场和(或)对流强度来判别南海夏季风的爆发日期。这种方法在大多数的年份是适用的,但是2006年由于0601号台风"珍珠"的介入,利用南海地区的区域指标来确定南海夏季风的爆发日期就略显不足。要解决以上的问题,必须从更大尺度上去想办法。利用经圈和纬圈环流可以较好地确定2006年南海夏季风的爆发日期。分析结果表明2006年南海夏季风爆发于5月16日(第4候)。

Since the South China Sea （SCS） summer monsoon （SCSSM） is pronouncedly featured by abruptly intensified southwesterly and obviously increased precipitation over the SCS, the lower-tropospheric winds and/or convection intensities are widely used to determine the SCSSM onset. The methods can be used in most of the years but not in 2006. Due to the intrusion of Typhoon Chanchu （0601） that year, the usual method of determining SCSSM onset date by utilizing the SCS regional indices is less capable of pinpointing the real onset date. In order to solve the problem, larger scales have to be taken into account. Zonal and meridional circulations would be better to determine the break-out date of SCSSM in 2006. The result indicates that its onset date is May 16.