摘要
利用先进的信号检测技术——多窗谱方法(MTM),对1856～1998年的南、北半球月平均温度序列进行多种信号的检测、重构,系统对比了年代际振荡信号在南北半球、海陆表面及不同季节的差异,进而研究其对变暖显著性的影响。结果表明近150年来,南北半球平均温度变率中,变暖趋势占主导地位。但北半球年平均温度的变暖背景上还叠加着显著的40年、60～70年的准周期振荡,导致其线性增暖的显著性、稳定性都较南半球低,夏季尤为明显。海陆对比,海洋上年代际振荡信号较陆地明显,线性增温率略低于陆地, 但稳定性较高。值得注意的是,年代际振荡信号已在20世纪90年代中达到峰值,近期已开始下降,这有可能影响北半球未来气候增暖的速率。同时通过对海气耦合模式数值模拟结果的初步分析,表明观测到的增暖趋势与海气系统内部的自然变率无关,年代际振荡可能是海气系统的固有振荡。
On the basis of Multi-Taper spectral analysis, the work not only has examined and reformed monthly mean temperature time series of Northern and Southern Hemisphere from 1856 to 1998, but also has systematically contrasted the differences of interdacadal oscillation (IDO) between S-N hemisphere, ocean-land surface in different seasons, with especial analysis of IDO signals effects on global warming. The results shows that warming trend plays a dominant role in S-N hemisphere mean temperature variability during the last 150 years. However, there are the significant IDO with periods of about 40, 60～70 years super-imposed on a linear warming trend for Northern Hemisphere mean temperature which leads to the diminishing the linear warming rate in terms of its significance and stability, as opposed to that in Southern Hemisphere, especially in summer. Moreover, in comparison of land to sea surface temperature, IDO signals detected in the latter are found to be more remarkable than those in the former, as contrasted to the linear warming rate. It has been noticed that IDO shows its peak value in the middle 1990s, and begins to descend recently, a fact which probably affects on the coming warming rate of Northern Hemisphere mean temperature. Meanwhile, In terms of the GCM results from the HadCM2 model, preliminary analysis implies that the IDO may be the inherent oscillation of the ocean and atmosphere system, but warming trends are not related to natural variability.
出处
《热带气象学报》
CSCD
北大核心
2003年第2期122-136,共15页
Journal of Tropical Meteorology
基金
南京气象学院重点实验室基金项目(编号KLME010208)
江苏省"青蓝工程"基金项目共同资助
