一个新的ENSO监测指标的研究

利用1982～1996年逐月平均SST和OLR资料，首先通过奇异值分解（SVD）技术研究了热带太平洋大气对流活动和海温场的时间和空间结构及其相互关系。结果表明，第一模态都明显地反映出ENSO信息，两场间具有很高的相关。分析了80年代以来的E1 Ni?o/La Ni?a盛期的热带太平洋对流活动场以及NINO 3指数与OLR场的点相关，结果指出，中东太平洋和西太平洋上存在类似偶极子型的两个符号相反的相关区，与SVD第一模态空间分布型十分相似。由此建立了反映ENSO期间热带中东太平洋和西太平洋反向变化的对流涛动

A New Index for ENSO Monitoring

Based on monthly mean SST and OLR data during 1982~1996 and by applying Singular Value Decomposition (SVD) technique and correlation analysis, a new index for ENSO monitoring system is studied. The results show that tropical Pacific SST and OLR fields are significantly correlated. The first models of these two fields derived from SVD clearly indicate ENSO signals. According to the analyses of the structure of OLR anomaly fields in the mature phases of both E1 and La , and the spatial correlation between NINO3 index and the tropical Pacific OLR field, this paper reveals that the pattern of the opposite centers like dipole over the tropical Pacific in OLR field is quite similar to the structure over the equatorial Pacific for the first modes of both OLR and SST. A Convective activities Oscillation Index (COI) is thus derived for the opposite variation striation of OLR between the eastern-central Pacific and the western Pacific. Further analyses have confirmed that COI is a sensitive index to reflect ENSO signal. The correlation between COI and NINO 3 index is higher than the other indices (including SOI) used in operational ENSO monitoring system worldwide