采用1950年1月至1999年12月SODA海洋上层温度的月平均资料及同期的NCEP月平均风场资料,研究了印度洋表层和次表层热含量年际变化的特征以及与海面风场的关系。通过对热带印度洋海区上层热含量异常的经验正交函数分解,发现表层与次表层热含量主要模态的分布不同,表层热含量主要模态的时、空分布与前人对海表温度(SST)异常的研究结果基本一致,第一模的空间分布为全海盆一致型,春季(夏季)表层热含量第一模的时间序列与前一年的秋季(冬季)Nino3区SST异常的时间序列有密切的关系;第二模的空间分布为东西偶极子型,并在秋季与4-8个月前的Nino3区SST异常有密切的关系;次表层热含量异常第一模为东西偶极子型,冬季热带太平洋异常通过影响印度洋的海面风导致的海洋动力调整,进而影响印度洋次年春季次表层热含量东西偶极子型异常;次表层热含量异常第二模在10°S以北是全海盆一致型,但却与Nino3区SST异常在统计学上无关。
The temperature data from SODA and sea surface wind data from NCEP during 1950-1999 were used to investigate the interannual variation characters of the surface and subsurface heat contents in Indian Ocean and their relationship with ENSO by EOF analysis. The results show that the dominant modes of the interannual variations are different between the surface and subsurface heat contents. The space pattern of the dominant mode of the surface heat content anomaly is similar to that of the SST anomaly. The first mode of the surface heat content is a basin mode, and there are close relations between the first mode time series in summer (autumn) and the Nino3 index in autumn (winter) of last year. The second mode of the surface heat content is an east-west dipole mode, and in autumn the time series of the dipole mode has a close correlation with the Nino3 index 4-8 months earlier. The first mode of the subsurface heat content is east-west dipole mode, which is resulting from the influence on the spring thermocline by the El Nino (or La Nino) in winter of last year via sea surface wind anomaly and ocean dynamic adjustment. But the second mode time series of the subsurface heat content does not have any relationship with SST anomaly in Nino3 statistically.