【作者】 程军；

【导师】 郭品文； 于非； 蒲书箴；

【作者基本信息】 南京信息工程大学 ， 气象学， 2005， 硕士

【摘要】 本文利用JEDAC、NCEP、SODA、WOCE等资料,对北太平洋上层热含量、大气要素场以及平流热输送和验潮站水位进行了系统的分析,研究表明: 1.北太平洋上层海洋热含量存在25年左右的年代际变化和5年左右的年际变化,年代际尺度为其主要变化模态。年代际的空间分布呈“马蹄”形。年际尺度变化落后ENSO事件7个月。 2.北太平洋区域的大气要素场也存在显著的年代际变化特征,且演变过程是同步的,表现出显著的一致性。 3.大气要素场的年代际演变同上层海洋热含量的趋势存在很好的相关。 根据上述关系,得出了一个存在于上层海洋热过程和阿留申低压系统之间的海气耦合模型。即:上层海洋热积聚时,海表热通量为负异常,阿留申低压减弱,使得海表热通量减弱更甚,上层海洋热积聚加强,这是正反馈;而弱的阿留申低压所产生的弱西风又可使得经向的表层Ekman输运和垂直混合减弱,同时随着上层海洋的热积聚,使得SST迅速升高,逐渐增大的海气温差使得海表热通量增加,热积聚过程受抑制,这是负反馈;当海表热通量恢复正常时,正反馈消失,负反馈效应达最大,使得海表热通量变为正异常,上层海洋转为热散失过程。 该模型说明,中纬度北太平洋海气耦合系统可以产生年代际振荡。 4.西北太平洋区域的平流热输送同样存在显著的年代际演变特征,验潮站水位资料提供了佐证。通过对比分析可知,平流热输送是与北太平洋海气耦合系统的年代际演变相适应的。 5.北太平洋气候系统存在长、短两个主要的年代际周期,长、短周期相互叠加,共同主导着气候系统的年代际演变。当长、短年代际周期零振幅、同趋势交汇时,北太平洋气候系统似乎就会发生系统性突变。更多还原

【Abstract】 The upper layer heat storage, atmosphere elements and the thermal advection of North Pacific has been analyzed here on the basis of some variable data from JEDAC, NCEP, SODA and WOCE. Results show that:1. The features of interdecadal variation of upper layer heat storage with a 25-year period are obvious in the North Pacific Ocean. The heat storage anomalies in the central north pacific surrounded by horseshoe pattern.2. Observations of atmosphere elements reveal interdecadal timescale, coherent variations.3. A simple coupled ocean-atmosphere mechanism is built between the upper layer heat process of North Pacific and the Aleutian Low system based on above result.When the upper layer ocean heat accumulates, the sea surface heat-flux is restrained, Aleutian Low is weak, westerly over North Pacific is sequentially weak, the weak westerly makes the sea surface heat-flux weakened further, the upper layer ocean heat accumulate more, that’s a positive feedback; weakened westerly reduce the sea surface Ekman transport and the vertical mixing, with the raise of quantity of the upper layer heat, SST raises quickly, the increasing ocean-atmosphere temperature difference increase the sea surface heat-flux, the process of accumulating heat is restrained, that’s negative feedback; when the sea surface heat flux becomes normal, the positive feedback disappear, the negative feedback come to the most power, that bring the sea surface heat flux become positive anomaly, upper layer ocean inverse to the process of dissipating heat.The mechanism indicates that the coupled ocean-atmosphere interaction can generate interdecadal fluctuation.4. The flux, heat flux and thermal advection of Kuroshio and Kuroshio Extension character with notable interdecadal variability. The analysis results of sea levelconfirm the interdecadal characters of the flux and heat transport too. Comparing the heat transport with the sea surface heat-flux, we can know that the heat transport is consistent with the coupled ocean-atmosphere interaction mechanism of North Pacific climate interdecadal variation.5. There are two main interdecadal periods in the North Pacific climate system. The short period is 20-30 years and the long period is 50-70 years, which makes the interdecadal variation very complex in the North Pacific climate. When the long period and the short period intersect with the zero swing and the same trend, the regime shift of the North Pacific climate seems to be happened.更多还原