Simulation of the climate impact of Mt. Pinatubo eruption using ECHAM5 – Part 2: Sensitivity to the phase of the QBO and ENSO
Simulation of the climate impact of Mt. Pinatubo eruption using ECHAM5 – Part 2: Sensitivity to the phase of the QBO and ENSO
复制标题
使用 ECHAM5 模拟皮纳图博火山喷发的气候影响 – 第 2 部分：对 QBO 和 ENSO 相位的敏感性
DOI：
10.5194/acp-9-3001-2009
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发表时间：
2008
影响因子：
6.3
通讯作者：
G. Stenchikov
中科院分区：
文献类型：
--
作者：
M. Thomas;M. Giorgetta;C. Timmreck;H. Graf;G. Stenchikov
抽象的。研究了热带和温带皮纳图博火山喷发对不同 QBO 阶段气候影响的敏感性。皮纳图博山于 1991 年 6 月在 30 hPa 的 QBO 东风相期间喷发，并于 1992 年 8 月发生西风相变化。这里分析了如果皮纳图博山喷发期间 QBO 相处于相反位相的后果。因此，在本研究中，使用ECHAM5大气环流模型的中层大气配置对两种情况进行了模拟——一种是观测到的QBO相，另一种是相反的QBO相。平流层下部温度和位势高度的响应在以下情况下进行评估：(1) 仅包括 QBO 的影响时；(2) 包括气溶胶、QBO 和 SST（组合响应）的影响时。平流层较低温度下的热带 QBO 特征在纯 QBO 响应和组合（气溶胶 + 海洋 + QBO）响应中得到了很好的捕捉。在联合强迫的情况下，真实地捕捉到了QBO喷发后第二个冬季温带大气对QBO的响应，显示出当QBO处于西风相时极地涡旋增强，而在东风QBO相时则显示出温暖、弱的极地涡旋。无论组合响应中的 QBO 相位如何，涡旋在第一个冬季都会受到干扰，这可能是由于喷发后第一个冬季厄尔尼诺现象的强烈影响所致。然而，纯QBO实验并不能真实地再现西风QBO阶段极地涡旋的加强，即使在10月-11月-12月，当规定相反的QBO阶段而不是这里使用的12月-1月-2月冬季月份进行平均时，高纬度地区的气温低于正常水平。
Abstract. The sensitivity of the climate impact of Mt. Pinatubo eruption in the tropics and extratropics to different QBO phases is investigated. Mt. Pinatubo erupted in June 1991 during the easterly phase of the QBO at 30 hPa and the phase change to westerly took place in August 1992. Here, the consequences are analyzed if the QBO phase had been in the opposite phase during the eruption of Mt. Pinatubo. Hence, in this study, simulations are carried out using the middle atmosphere configuration of ECHAM5 general circulation model for two cases – one with the observed QBO phase and the other with the opposite QBO phase. The response of temperature and geopotential height in the lower stratosphere is evaluated for the following cases – (1) when only the effects of the QBO are included and (2) when the effects of aerosols, QBO and SSTs (combined response) are included. The tropical QBO signature in the lower stratospheric temperature is well captured in the pure QBO responses and in the combined (aerosol + ocean + QBO) responses. The response of the extratropical atmosphere to the QBO during the second winter after the eruption is captured realistically in the case of the combined forcing showing a strengthening of the polar vortex when the QBO is in its westerly phase and a warm, weak polar vortex in the easterly QBO phase. The vortex is disturbed during the first winter irrespective of the QBO phases in the combined responses and this may be due to the strong influences of El Nino during the first winters after eruption. However, the pure QBO experiments do not realistically reproduce a strengthening of the polar vortex in the westerly QBO phase, even though below normal temperatures in the high latitudes are seen in October-November-December months when the opposite QBO phase is prescribed instead of the December-January-February winter months used here for averaging.