热带印度洋上层热含量异常场的年际变率分析

Analysis for Interannual Variability of Heat Content Anomaly in the Upper Tropical Indian Ocean

利用1950—2006年间日本气象局月平均温、盐度资料,分析了热带印度洋热含量异常场的年际时空变化特征,并分别探讨了热含量年际变异与ENSO、印度洋偶极子(IOD)、南印度洋偶极子(SIOD)和热带印度洋纬向风异常的关系。结果表明,热带印度洋热含量异常场的年际振荡是由空间结构不同但变化周期相近的两个主要模态构成的,这两个模态的振荡周期均为2～6 a,但第二模态更像是第一模态的前期发展阶段;热带印度洋热含量异常的年际振荡可能对ENSO循环和印度洋偶极子有1～9个月和3～11个月的超前影响,可作为ENSO和IOD的指示因子,但它对SIOD则有约2个月的滞后响应;赤道印度洋的纬向风异常是热带印度洋热含量年际振荡的重要影响因素。

The monthly thermohaline data （1950-2006） from Japan Meteorological Agency are used to analyse the interannual spatial and temporal characteristics of the tropical Indian Ocean heat content anomaly field, and to discuss its relationships respectively with ENSO, the Indian Ocean Dipole（IOD）, the South- ern Indian Ocean Dipole（SIOD）, and the tropical Indian Ocean zonal wind anomalies. The results show that the interannual oscillation of the tropical Indian Ocean heat content anomalies is comprised of two main modes with spatial structures different from each other and 2- 6 year period similar to each other, but the second mode would be rather like the early development stage of the first mode. The interannual oscillation of the tropical Indian Ocean heat content anomalies may 1 -9 months lead the ENSO cycle and 3-11 months lead the IOD variation, but about 2 months lag behind the SIOD variation. The equatorial Indian Ocean zonal wind anomaly is one of the important factors effecting on the interannual oscillation of the tropical Indian Ocean heat content.