太平洋海气相互作用的时空变化

THE TEMPORAL AND SPATIAL VARIATIONS IN AIR-SEA INTERACTION OVER THE PACIFIC OCEAN

中文摘要:

      本文根据1957-1976年赤道太平洋海温和北太平洋海平面气压的月平均资料,计算了它们之间全年(1-12月)逐月的时滞相关,分析了北太平洋副热带反气旋影响赤道海温和赤道海温对副高反馈的季节变化.发现它们之间的联系不同季节、不同地区有明显差异:副热带反气旋对赤道海温的影响(负相关)以春季最大,秋季最小;赤道海温的反馈,对副高的不同部分作用不同,对副高主体的作用(正相关)以冬半年最大、夏半年较小(尤其是盛夏),对西部副高脊的作用(负相关)相反,以夏半年最大,冬半年较小.其过渡期为5月和11月.同时对其季节变化的可能原因也提出了一些初步看法.其中特别强调了大型环流背景的基本状态(包括平均垂直环流)对海气相互作用过程的重要性.

英文摘要:

      Based on the monthly mean data of 1957-1976,the lag correlations between the monthly sea level pressure field over the North Pacific and the sea surface temperature (SST) averaged over the equatorial East Pacific region (5°N-5°S, 80°W-180), including the SST time-lagging by 6 months to time-leading by 6 months, are computed. The seasonal variations in the interaction between the subtropical high systems over the North Pacific and the equatorial East Pacific SST are discussed. It is found that the surface subtropical anticyclone over the eastern part of the North Pacific is negatively correlated to the equatorial East Pacific SST which lags behind the former on the average by 2-3 months, and the correlation between them is best in spring and poorest in autumn. The feedback impact of the equatorial East Pacific SST on the subtropical high in the middle troposphere behaves differently in different part of this high. Its effect on the main body of subtropical high that has a positive correlation with the SST with the latter leading on the average by 4 months is largest in winter half year and smaller in summer half year, especially in mid-summer. While the effect on the subtropical ridge over the West Pacific that shows negative correlation with the SST with the latter leading on the average by 2-3 months is largest in summer half year and smaller in winter half year. Their transition periods are May and November. Further, some possible causes of such seasonal variations are suggested, in which we emphasize the significance of seasonal variation in the basic state of the background flow, especially in the mean zonal and meridional circulation and their interaction.