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本文利用再分析资料和耦合模式FGOALS_gl的20世纪气候模拟实验(20C3M)的结果,在检验模式对西北太平洋副热带高压(西太副高,西太反气旋)模拟性能的基础上,通过对再分析资料和模拟的850hPa风场做EOF分解,揭示出西太副高年际变率的两种模态;按照它们对应的赤道异常纬向风的不同,将这两种模态分别命名为“赤道东风共存模态”(EEM)和“赤道西风共存模态”(EWM).两种模态的西太异常反气旋形成机制类似,但维持和发展机制不同,主导振荡周期不同,与ENSO位相的关系不同.EEM的西太异常反气旋产生于前冬ElNio衰减期,通过西北太平洋局地海气正反馈维持到夏季,并可通过增强赤道次表层海水上翻促进ElNio向LaNia位相的转变.EWM的西太异常反气旋形成于当年春季,主要依靠同期赤道中东太平洋的异常暖海温强迫而维持和发展.FGOALS_gl模式能再现上述两种模态,但不能正确反映它们的相对重要性.在NCEP资料中,EEM表现为第一模态,解释了总方差的35.6%;而在模式中,EWM表现为第一模态,解释了总方差的68.2%.
Based on the results of the 20th century climate simulation experiment (20C3M) based on the reanalysis data and the coupling model FGOALS_gl, based on the simulation performance of the test pattern on the subtropical high in the western North Pacific (West Pacific subtropical high and Western Pacific anticyclone) The data and simulated 850hPa wind field do EOF decomposition, revealing two modes of the interannual variability of the West Pacific subtropical high. According to their different equatorial zonal winds, the two modes are named as " (EEM) and EWM (Equator Mode of the Equatorial Westerly), the formation mechanism of western anomalous anomalous anticyclones in the two modes are similar, but the mechanism of sustaining and developing is different and the dominant oscillation periods are different, Which has a different relationship with the ENSO phase.The western Pacific anomalous anticyclone of the EEM was generated during the pre-winter ElNio decay period and was maintained to the summer through the positive feedback of the local ocean currents in the northwestern Pacific Ocean and promoted the ElNio to LaNia phase by enhancing the equatorial subsurface sea- .While the Western Pacific anomalous anticyclone of the EWM was formed in the spring of that year and mainly sustained and forced by the abnormal warm SST anomaly in the equatorial central and eastern Pacific Ocean, the FGOALS_gl model can reproduce the above two modes, but it can not correctly reflect it . The relative importance of the data in the NCEP, EEM performance of a first mode, the total variance explained 35.6%; in mode, the first mode the performance of the EWM explained 68.2% of the total variance.