ENSO与热带西北太平洋海洋上层热含量及副热带高压变异的关系

THE RELATIONS OF ENSO TOVARIABILITIES OF THE HEAT CONTENTOF THE OCEANIC UPPER LAYER ANDSUBTROPICAL HIGH PRESSUREIN THE NORTHWEST PACIFIC

本文使用谱分析法,分析了ENSO与热带西北太平洋海洋上层热含量和副热带高压的多年变化及其相互关系。文中以南方涛动指数(SOI)距平表征ENSO,以海面至100m水层的平均温度(Tav)代表上层热含量,以Tav>27℃网格数(HC)的季距平代表热含量的变化,以西太平洋副热带高压的面积指数(ST)表示其多年变化。分析结果表明,这三个时间序列的持续性良好,它们有相似的自振韵律和一个共同的谱峰,主要振荡周期均为3～4a。交叉谱分析表明,在这一振荡周期上,这些时间序列有较高的凝聚,且SOI和HC同相,而HC和ST反相变化,即SOI为负距平时,HC也为负距平,而ST为正距平,SOI先于HC两个月,而HC先于ST6个月左右。

The relationships between Southeprn Oscillation Index (SOI), area index of the subtropical high pressure over western pacific (ST)and heat content of the oceanic upper layer in the tropical northwest Pacific (HC)were discussed by using method of spectral analyses. In this paper ,the HC is defined as number of grid -point at which the averaged temperature (TAV)from the sea surface to 100 meter depth is above or equal to 27℃ (i.e. TAV≥27℃ ).Power-spectral analyses show that during 1964-1982,variations in the SOI.STand HC have a similar self-oscillation rhythm and common spectral peak (period for 3 to 4 years ).Cross-spectral analyses between the SOI and HC.and between the ST and HC show significant coherence in these spectral peaks.The SOI leads the HC by two months , and the HC leads the ST by about 6 months .The SOI is in phase with the HC,and the ST is out of phase with the HC.