Arizmendi Fernando, Barreiro Marcelo
Departamento de Ciencias de la Atmósfera, Instituto de Física, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay.
Chaos. 2017 Sep;27(9):093109. doi: 10.1063/1.5004535.
Using functional network analysis, we study the seasonality of atmospheric connectivity and its interannual variability depending on the different phases of the El Niño-Southern Oscillation (ENSO) phenomenon. We find a strong variability of the connectivity on seasonal and interannual time scales both in the tropical and extratropical regions. In particular, there are significant changes in the southern hemisphere extratropical atmospheric connectivity during austral spring within the different stages of ENSO: We find that the connectivity patterns due to stationary Rossby waves differ during El Niño and La Niña, showing a very clear wave train originating close to Australia in the former case, as opposed to La Niña that seems to generate a wave train from the central Pacific. An attempt to understand these differences in terms of changes in the frequency of intraseasonal weather regimes cannot fully explain the differences in connectivity, even though we found the prevalence of different intraseasonal regimes in each phase of ENSO. We conclude that the differential response to extreme phases of ENSO during austral springtime is related to the forcing of waves of different tropical origins.
利用功能网络分析，我们研究了大气连通性的季节性及其年际变化，该变化取决于厄尔尼诺-南方涛动（ENSO）现象的不同阶段。我们发现，热带和温带地区在季节和年际时间尺度上的连通性都有很强的变化。特别是，在ENSO的不同阶段，南半球温带地区的大气连通性在南半球春季有显著变化：我们发现，在厄尔尼诺和拉尼娜期间，由静止罗斯贝波引起的连通性模式不同，在前一种情况下，有一个非常明显的波列起源于澳大利亚附近，而拉尼娜似乎产生了一个从中太平洋出发的波列。尽管我们发现在ENSO的每个阶段不同季节内天气状况的频率普遍存在差异，但试图从季节内天气状况频率变化的角度来理解这些差异并不能完全解释连通性的差异。我们得出结论，南半球春季对ENSO极端阶段的不同响应与不同热带起源的波的强迫有关。
