1997年的强ENSO事件

A STRONG ENSO EVENT IN 1997

关键词:  强ENSO  诊断  影响

Key words:  Strong ENSO  Diagnosis  Influence

摘要:

根据目前的海洋-大气资料,对普遍关注的1997年3月在热带太平洋开始形成的一次新的强ENSO事件进行了诊断研究,结果表明:赤道中、东太平洋大范围持续增温1-4℃、热带印度洋海温也同步增暖。SOI持续异常低值,但还不及1982/1983年的强度。赤道太平洋对流层低层信风异常减弱,高层东风加强。OLR低值中心和最大负距平中心东移,赤道中太平洋对流活动加强。环太平洋沿岸热带地区出现明显旱涝异常。此次ENSO事件的进一步发展,将成为本世纪最强的一次ENSO事件。与1982/1983、1986/1987年两次强ENSO事件进行了比较,以期提高对这一热带太平洋海洋-大气异常最强信号的认识,为作好年度气候趋势预测提供大尺度的背景场条件。

Abstract:

In the paper,according to ocean-atmospheric data up to now, a new strong ENSO event which human follow with interest, starting from March 1997,has been diagnosed.The result indicates SSTs continue to increase 1-4℃ in equatorial mid-eastern Pacific area, meanwhile SSTs in tropical Indian Ocean also warms.The southern oscillation index maintains lower value but it doesn't get as strong as that in 1982/1983 year. Lower equatorial Pacific troposphere trade-wind weakened, corresponding to intensified upper troposphere easterly wind.The OLR minimum value center and OLR maximum negative anomaly center move towards the east. Convection over the mid-equatorial Pacific intensified. The evident drought and flooding anomaly occurred in the region around Pacific. If this ENSO event develops in the future, it will be the strongest ENSO event in the century. We compared with last two strong ENSO event in 1982/1983 and 1986/1987 year. Authors' purpose is to enhance understanding of the strongest signal of tropical Pacific ocean-atmosphere anomaly, a large-scale background field condition is given for making yearly climate tendency prediction.