【作者】 祁莉；

【导师】 管兆勇； 何金海； 张祖强；

【作者基本信息】 南京信息工程大学 ， 气象学， 2008， 博士

【摘要】 本文利用NCEP/NCAR再分析数据集,中国台站资料以及TRMM卫星降水资料等,分析了西太平洋副热带高压双脊线的动力学和热力学特征,揭示了副高双脊线的建立过程和影响因子,指出了双脊线过程对副高中短期南北进退(特别是不连续进退)的作用,并结合副高动力学理论探讨了这种作用的物理机制。得到了以下主要结论:1、深入系统地阐明了“副高双脊线”的新概念。通过诊断分析和数值模式相结合的方法,揭示了这一独特现象存在的普遍性、地域性和季节锁相特征。它在模式中也有较好体现,很可能是大气环流变化中的一种固有形态。它的出现改变了水汽输送通道,形成“双雨带”,它的结束对西太平洋副热带高的不连续南北进退有重要影响。2、指出了西太平洋副热带高压双脊线建立过程的气候特征,可归纳为五种类型:赤道缓冲带北上型、季风槽东进型、中太副高西伸型、西风脊/大陆高压南压型以及副高原脊线断裂分离型。3、东亚季风偏强年西太平洋副热带高压双脊线过程较频繁。此外,西太平洋副热带高压双脊线的形成受南海夏季风10-20天振荡控制,同时受30-60天振荡调控。因此,西太副高双脊线过程的形成与东亚季风(季风槽)的变异和低频振荡关系密切。4、揭示了一类西太副高双脊线过程的维持机制。这类双脊线过程表现为南侧新生脊线加强发展并最终取代北侧脊线,造成副高异常偏南。在该类双脊线发展过程中,西太平洋副热带高压南侧东风波向西传播,并与西太平洋副热带高压相互作用,这可能改变了副高区域垂直流场,进而增强副高南侧脊线,造成该类双脊线过程结束后南侧脊线能够取代北侧脊线。这类西太平洋副热带高压双脊线过程对副高脊线的不连续南撤提供了先兆。这对副高预报有一定的预示作用。更多还原

【Abstract】 NCEP/NCAR reanalysis dataset, China stations data and TRMM rainfall data are used to document the interesting phenomenon defined as West Pacific Subtropical High (WPSH) double-ridges. Dynamics and thermodynamic characteristics are analyzed to explore the onset processes and affecting factors of the WPSH double-ridges, as well as its possible impact on WPSH progress northward and retrogress southward on a short-and-middle-term basis, especially discontinuous movement. Corresponding physical mechanism is discussed by means of subtropical high dynamics theory. Main conclusions are made as follows:1. The new concept of WPSH double-ridges is illustrated in system and depth. Diagnosis analysis in combination with modeling method is employed to show the universality, geographical preference and phase locking of the phenomena. It is also represented well in the model, indicating that this phenomenon may be one natural shape of general circulation variation. Appearance of the double-ridges changes the water vapor transportation channels and forms two rain-belts. End of the double-ridges plays important role on WPSH discontinuous progress northward and retrogress southward.2. Onset process of WPSH double-ridges is indicated on a climatic basis. It could be concluded into five types: equatorial buffer zone moving northward, South China Sea monsoon trough progressing eastward, Middle Pacific subtropical high extending westward, westerly ridge or continental anticyclone suppressing southward and the original WPSH ridge breaking into two parts and separating with each other.3. The WPSH double-ridges is much more frequent during stronger Asian summer monsoon year. Furthermore, the formation of the WPSH double-ridges is controlled by 10-20-day oscillation of South China Sea summer monsoon, and further modified by 30-60-day oscillation. On this account, the formation of WPSH double-ridges is closely related with Asian monsoon or monsoon trough aviation and intraseasonal oscillation.4. One type of WPSH double-ridges process is analyzed to find possible mechanism of maintenance. This type of WPSH double-ridges process presents as that the new-born ridge in the southern flank of subtropical high develops and takes place of the original ridge in the northern flank of WPSH finally, leading to the WPSH anomaly southward than usual. The formation, maintenance and disappearance of this type of double-ridges processes have close relationship with propagation of the easterly waves from southeast to northwest on the periphery of the southern flank of subtropical high, as well as the reaction with the WPSH. It may change the distribution of vertical motion in the subtropical high regions, and further strengthen the southern ridge which replaces the northern ridge later. This type of WPSH double-ridges process provides foreboding for subtropical high ridge discontinuous retrogression southward and be attributed for WPSH forecast.更多还原