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作为气候系统中的重要成员,热盐环流在20世纪的演变特征对于其自身演变规律及其相应气候影响的研究十分关键.研究该问题两种途径(直接观测与间接重建)的结论存在显著差异(减弱与非减弱),且可信度皆有待进一步提高.本文基于热盐环流强度改变所引起的最显著气候影响—南北半球间海气界面温度(表面海温及气温)的“翘翘板”现象,在两种可能的演变情形下,由相应的模式试验建立海气界面温度“跷跷板”现象强度与热盐环流强度异常间的统计模型,继而由多个实测海气界面温度资料集对该时期热盐环流的强度异常进行重建.模式试验结果表明,减弱情形下热盐环流的强度异常与“跷跷板”现象的强度之间在10a以上尺度范围内显著相关,非减弱情形下两者在40a以上尺度范围内显著相关.本文两种情形下的重建结果相一致,同时指出工业革命以来热盐环流的演变经历了“减弱-增强-减弱-增强”4个阶段,且年代以上尺度范围内的变化幅度约1Sv.4个演变阶段的转换时间分别为20世纪10年代中期、20世纪40年代及20世纪70年代中期.本文结论进一步验证了前人的重建结果,指出该时期热盐环流可能未发生趋势性的减弱,还是以年代际波动为主.
As an important member of the climate system, the evolution of the thermohaline circulation in the 20th century is crucial for the study of its own evolution law and its corresponding climate impact. There are significant differences between the two approaches (direct observation and indirect reconstruction) (Weakened and non-reduced), and the credibility of them all needs to be further improved.This paper based on the most significant climatic impact caused by the change of thermohaline circulation intensity: the change of the sea surface temperature (surface sea temperature and air temperature) between the northern and southern hemispheres In the two possible evolutional situations, the statistical model between the oceanic temperature, the “seesaw” phenomenon and the abnormality of the thermohaline circulation strength is established by the corresponding model test, The temperature data sets reconstruct the anomaly of the circulation of the thermohaline circulation in this period.The results of the model tests show that the intensity anomaly of the thermohaline circulation is significantly related to the intensity of the “seesaw” phenomenon in the range of 10 a to 10 a Which are significantly correlated with the scale above 40a in the weakening case.The reconstructed results in the two cases are consistent with the evolution of the thermohaline circulation since the Industrial Revolution Experienced four stages of “weakened-enhanced-weakened-enhanced” and the change range of about 1Sv within the range of the scale of the above-mentioned period was changed from the mid-10s of the 20th century to the 1940s of the 20th century In the mid-1970s, the conclusion of this paper further validates the results of the predecessors’ reconstruction, pointing out that the circulation of thermohaline circulation may not be weakened or decadal fluctuations in this period.