本研究計畫－「影響東亞季風降水年際變化的主要振盪形態與機制(II)」，是「東亞季風降水年際變化」整合型計畫的第三子計畫。本計畫的主要目的就是希望利用經驗正交模分析方法(empirical normal mode analysis; ENMA)直接從實際觀測與重新分析資料得到其中的主要振盪形態來探討影響東亞季風降水年際變化的主要波動結構與動力機制。我們預計將利用台灣與東亞地區的月與侯平均降水觀測資料、NCEP/NCAR 和 EC（ERA40）重新分析資料，經由ENMA 方法得到其主要正交模、利用Monte Carlo simulation 估計所萃取的經驗正交模的統計顯著性、利用資料延展法更準確的把主要正交模的週期萃取出、再分析主要正交模各個變數之間的關係來萃取與探討影響東亞季風降水年際變化的主要因子並建立影響東亞季風降水年際變化的主要可能機制。另一方面，我們也預計將利用研究群的模式模擬資料，經由ENMA 方法得到其主要正交模並與從實際觀測與重新分析資料得到的結果進行比對，希望可以讓我們更深入瞭解數值模式不足之處並尋求改進之道。 This is the third subproject entitled 「Principal oscillation patterns and associated mechanisms of the East Asian monsoon rainfall variability (II) 『of the integrated projects -「The interannual variability of East Asian monsoon rainfall」. The main motivation of this project is, by extracting and studying the dominant empirical normal modes of the observed and GCM data, to investigate the dominant factors and mechanisms affecting the East Asian monsoon rainfall variability. The goal of this year is to use the observed monthly and pentad averaged rainfall data from Taiwan and East Asia regions, the NCEP/NCAR reanalysis, as well as ERA 40 reanalysis, through ENMA extracting their normal modes, Monte Carlo simulation testing their statistical significance, extending data to better resolving periods of the dominant modes, to study the dominant factors and mechanisms affecting the East Asian monsoon rainfall variability. At the same time, we also plan to use GCM simulated data provided by other subprojects of this integrated projects, following the same methodology as above and comparing results with those derived from observed data, to identify the drawbacks of GCMs and to provide ways to improve them. 研究期間：9408 ~ 9507
