Global eastward propagation signals associated with the 4–5-year ENSO cycle
Global eastward propagation signals associated with the 4–5-year ENSO cycle
复制标题
与4-5年ENSO周期相关的全球东向传播信号
作者：
S.;Xianan Jiang;Boniface O Fosu
海温距平（SSTA）的经度演化揭示了从北太平洋西部（WNP）在20°N附近向赤道中太平洋Niño-3.4地区缓慢的东南传播。其传播表现为一条狭窄的西南-东北向海温带，横跨副热带北太平洋，其传播过程约为2-3年。传播的海温似乎参与了El Niño-Southern振荡（ENSO）的启动。地表风异常、海平面气压异常、长波辐射异常和速度势异常均表现出明显的同步向东传播，这种传播似乎是绕全球的，并与ENSO周期的主要4-5年频率相耦合。结果表明，El Niño/La Niña引起的印度洋变暖/变冷、印度洋向WNP方向前进的海温和风异常以及北太平洋涛动的4 - 5年主导频率共同促成了报告的海温传播。研究结果表明，监测海温从西太平洋向热带中太平洋的传播可能有助于跟踪ENSO的发展。
Longitude-time evolution of sea surface temperature anomalies (SSTA) reveals a slow southeastward propagation from the western North Pacific (WNP) around 20°N to the Niño-3.4 region in the equatorial Central Pacific. The propagation is manifested as a narrow, southwest-northeast oriented SSTA band across the subtropical North Pacific, and its journey takes about 2–3 years. The propagating SSTA appears to engage the initiation of the El Niño–Southern Oscillation (ENSO). The anomalies of surface winds, sea level pressure, outgoing longwave radiation, and velocity potential all exhibit a concurrent and distinct eastward propagation, one that appears to be circumglobal and is coupled with the predominant 4–5 year frequency of the ENSO cycle. It is suggested that the previously found warming/cooling in the Indian Ocean induced by El Niño/La Niña, the progressive SSTA and wind anomalies across the Indian Ocean towards the WNP, and the predominant 4–5-year frequency of the North Pacific Oscillation collectively contribute to the reported SSTA propagation . The findings implicate that monitoring the SSTA propagation from the WNP towards the tropical central Pacific could be useful in tracking the ENSO development.