Testing of the Tropically Excited Arctic Warming Mechanism (TEAM) with Traditional El Nino and La Nina
Testing of the Tropically Excited Arctic Warming Mechanism (TEAM) with Traditional El Nino and La Nina
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DOI：
10.1175/jcli-d-12-00055.1
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发表时间：
2012-06-15
影响因子：
4.9
通讯作者：
Lee, Sukyoung
中科院分区：
文献类型：
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作者：
Lee, Sukyoung
利用欧洲中期天气预报中心(ECMWF)40年再分析(ERA-40)资料对厄尔尼诺和拉尼娜的合成过程进行了分析，证明了北极冬季(12-2月)的地表气温在拉尼娜期间异常温暖，而在厄尔尼诺期间却异常寒冷。地面和大气顶部的能量通量被用来计算合成的纬向平均极风向湿静力能量输送。结果表明，北极拉尼娜变暖与温带外能量向极地输送的增加有关。厄尔尼诺现象的特征正好相反。由于在拉尼娜期间热带对流加热比厄尔尼诺期间更为局部化，这些发现表明与ENSO有关的北极地面气温异常可能归因于热带激发的北极变暖机制(TEAM)。在热带地区，与以前的研究一致，厄尔尼诺期间的极地能量输送是正的，而拉尼娜期间是负的。考虑到关于变暖的世界是否会呈现出更多类似厄尔尼诺或拉尼娜的特征的争论，这项研究的结果强调了进一步调查热带对极地气候影响的必要性。
By analyzing El Nino and La Nina composites with 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) data, evidence is presented here that the surface air temperature of the Arctic winter (December-February) is anomalously warm during La Nina and cold during El Nino. Surface and top-of-the-atmosphere energy fluxes were used to calculate the composite zonal-mean poleward moist static energy transport. The result shows that the La Nina warming in the Arctic is associated with an increased poleward energy transport in the extratropics. The opposite characteristics are found for El Nino. Because the total tropical convective heating is more localized during La Nina than El Nino, these findings suggest that the Arctic surface air temperature anomalies associated with ENSO may be attributed to the tropically excited Arctic warming mechanism (TEAM). In the tropics, consistent with previous studies, the anomalous poleward energy transport is positive during El Nino and negative during La Nina. Given the debate over whether a warmer world would take on more El Nino-like or La Nina-like characteristics, the findings of this study underscore the need for further investigation of tropical influence on polar climate.