太平洋地区中低纬海气相互作用年代际振荡及其机制研究

Much attention has been given to the interdecadal anomalies air-sea system since the 1980s for the obvious strengthening of global climatic anomaly and ENSO oscillations. Seeing that the Pacific is the source of ENSO oscillations, we chose the interdecadal oscillation of air-sea interaction between the mid and low latitudes in the Pacific and its mechanism as the research subject of the project. The following innovative achievements have been obtained by use of internationally popular reliable data and suitable analysis methods: 1)Basal analysis work have been performed in the air-sea system anomalies and their interaction over the Pacific region and the global tropical oceans. The analysis results of real data confirmed that the interdecadal(interannual) variability dominates over the mid-high(low) latitudes. And their temporal-spatial characteristics and circulation patterns have also been carefully analysed. 2)The interdecadal variability of the relationships between North Pacific SSTA and flood season rainfall in North China, and between tropical Pacific SSTA and Indian summer monsoon rainfall has been revealed, and it has been pointed that the interdecadal variability has a control effect on the interannual one.3) The meridional circulation anomalies excited by EL Nino events has been separated from the mean meridional circulation in low latitudes, and the both has strengthened simultaneously since the 1980s. This is an important fact of the interdecadal variability of the low latitude air-sea system. 4) Analyses of thermal anomalies in a shallow lager of 0-400m in the tropical western Pacific showed that the most pronounced interdecadal signal exists at about 160 meter in depth in the tropical western Pacific, where may be also the key region of the ENSO decadal variability; Dynamic analysis conclusions may explain the new observational facts; So, the tropical western Pacific is of significance in the air-sea interaction over the tropical Pacific.

本课题将通过长时段观测资模式分析、藕合模式数值试验的方法，揭示太平洋地区海洋内部和大气内部的中低纬年代际相互作用模态，分析中、低纬度海气系统如何通过大气或海洋的“桥梁”作用而发生振荡的过程，最终讨论年代际振荡的可能机制。研究成果对认识海气年代际相互作用机制以及气候年代际异常成因都将具有重要意义。............