【文章內(nèi)容簡介】 左） /速度勢（右）與 Nino3指數(shù)的相關(guān)場 摘自：于衛(wèi)東、巢紀平， 自然科學(xué)進展 ， 2023 a b 圖 流函數(shù)（紅）、速度勢（黑）指數(shù)的時間演化 Research Progress ? Atmospheric circulation variability during ENSO The zonal wind anomaly is usually adopted as the indicator for the atmospheric circulation variation during ENSO. However, the more elegant general pictures are still desired. Walker circulation is closely associated ENSO, which is basically thermally driven. It corresponds the divergent circulation ponent. Meanwhile, the rotational ponent represents the atmospheric dynamic response. Thus it is valuable to depose the atmospheric motion into these two parts, evaluated by the stream function and velocity potential respectively. From the correlation map (), it can be seen that the atmosphere shows baroclinic response to the oceanic forcing. The Walker circulation is reversed in the sense of anomaly field. The lower level atmosphere is characterized by a cyclonic circulation pair, while the upper atmosphere by an anticyclonic circulation pair. During ENSO cycle, the divergent and rotational ponents vary in a rather consistent way, which can be verified from . The correlation between the two index exceeds . The correlation map between the stream function/velocity potential and Nino3 Index Ref: Yu W. and J. Chao, Advances in Natural Science, 2023 a b The index of the stream function (red) and velocity potential (black) 研究進展 ? ENSO循環(huán)中的大氣 海洋反饋過程 ENSO作為一種大氣 海洋相互作用事件 ， 通過海氣之間的正反饋過程得到發(fā)展 ， 通過負反饋過程完成位相轉(zhuǎn)變 ， 目前關(guān)于 ENSO循環(huán)中負反饋過程的認識有待于進一步加深 。 無旋大氣分量 ， 即翻轉(zhuǎn)的 Walker環(huán)流 ， 與海洋之間始終保持著正反饋 （ 圖略 ） 。 無輻散大氣分量 （ 圖 1） 在 El Ni241。o達到它的盛期之前和海洋之間存在著正反饋 ， 它的主要作用是使西太平洋赤道和赤道外海域的溫躍層抬升 ， 激發(fā)沿赤道東傳的暖 Kelvin波 ，造成西太平洋的海表面溫度降低 。 在 El Ni241。o達到盛期和之后的時間里 ， 無輻散大氣分量和海洋之間轉(zhuǎn)變成負反饋 ， 表現(xiàn)為關(guān)于赤道對稱的氣旋式環(huán)流移到了中東太平洋并且在西太平洋出現(xiàn)一對新的關(guān)于赤道對稱的反氣旋環(huán)流 ， 其中 ， 東移的氣旋式環(huán)流使東太平洋的溫躍層變淺 ， 造成溫度的降低 ， 而西太平洋新出現(xiàn)的反氣旋環(huán)流對加深了西太平洋的溫躍層 ， 使西太平洋海表面溫度升高 ， 這兩種負反饋過程共同造成了翻轉(zhuǎn) Walker環(huán)流的減弱 ， 并使 El Ni241。o向著它的相反為向轉(zhuǎn)化 ， 這一過程可以通過圖 2的示意卡通圖直觀的了解 。 圖 El Ni241。o過程中大氣 850hPa流函數(shù)演變的合成圖 圖 El Ni241。o過程大氣 海洋正負反饋過程的示意圖 Research Progress ? The atmosphereocean feedback during ENSO cycle ENSO is regarded as an atmosphereocean interaction process, which develops through the positive airsea feedback and decays through the negative feedback. The positive process is well understood. However, the negative feedback needs further investigation. The divergent atmospheric ponent, or the reversed Walker circulation, keeps the positive feedback with the ocean during the whole lifetime of El Ni241。o (fiures not shown). The case of the rotational atmospheric ponent is somewhat different (). Before the peak time of El Ni241。o, there is positive atmosphereocean feedback, which strengthens the development of El Ni241。o. However, this positive process stops from the peak time of El Ni241。o and converts to the negative feedback. This transition is realized through the eastward displacement of the cyclonic circulation pair over the centraltoeastern Pacific and the new emergence of the anticyclonic circulation pair over the western Pacific. Now the cyclonic circulation pair shoals the eastern Pacific thermocline and the anticyclonic circulation pair deepens the western Pacific thermocline. These two negative feedback processes greatly weakens the reversed Walker circulation and finally leads to the phase tran