热带西太平洋海洋上层热含量的分布特征及其年际变化的分析

THE HEAT CONTENT IN THE UPPER LAYER OF THE WESTERN TROPICAL PACIFIC OCEAN

选用海面至20℃等温线所处深度水层的平均温度来表征研究海域海洋上层热含量。利用这一特征值，分析1986—1990年期间热带西太平洋边缘海域海洋上层热含量在秋季的分布特征和年际变化。结果表明：（1）热含量呈南高北低分布，在7．5－22．1°N范围内。以130°E断面为代表，热含量的平均递减率为0．179（℃／纬度）；（2）热含量的分布主要取决于环流系统，其等值线因受黑潮和棉兰老海流的影响而由纬向分布转向经向分布。某些区域因受暖涡及冷涡的影响而呈封闭状分布；（3）热含量的年际变化与E1Nino事件存在着很好的相关性，在E1Nino事件发生期间，热含量变得很低，高热含量（大于26．5℃）海区的分布范围明显缩小。

Based on CTD data gathered in fall from 1986 through 1990 in the western Pacific by the 'R/V' Science 1, the distribution characteristics and interannual change of the upper-layer heat content were described and analysed in this paper, using the vertical-average temperature from surface to 20℃-isotherm depth as a representation of the upper-layer heat content. The results show that the upper-layer heat content is higher in the south and decreases northwards at a mean rate of 0. 179℃/Lat. from 7.5°N to 22.1°N along 130°E. The distribution of the upper-layer heat content is clearly associated with strong currents, such as the Kuroshio, Mindanao current and eddies. The higher heat content water is transported by the Kuroshio to the coast of southeast China.The higher and lower upper-layer heat content could be caused by the warm and cold eddies, respectively. Furthermore the interannual variation of the upper-layer heat content is greatly influenced by E1 Nino. The heat content becomes very low and the area of high heat content decreases rapidly after the appearance of El Nino.In addition, the interannual change in heat content is consistent with the change of the volume transport of the North Equatorial Current.