The Madden-Julian Oscillation in a warmer world
The Madden-Julian Oscillation in a warmer world
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DOI：
10.1002/2015gl065095
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发表时间：
2015-07-28
影响因子：
5.2
通讯作者：
Tsuang, Ben-Jei
中科院分区：
文献类型：
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作者：
Chang, Chiung-Wen June;Tseng, Wan-Ling;Tsuang, Ben-Jei
全球变暖对马登-朱利安振荡（MJO）的影响是使用少数几个能够再现其关键特征的模型之一进行评估的。在一个温暖的气候预测的世纪末，MJO的振幅增加（约30%）和频率，显示出更多的环全球传播的趋势。MJO的空间范围变得更大，更深，更带状延伸，但非带状局限。在非绝热加热场、水汽场和辐合场中，可以看到较强的垂直倾斜结构。我们的研究结果表明，这些变化的结果，通过耦合的动力学和热力学响应变暖的摩擦波条件不稳定性的第二类机制的加强。平均状态的增暖和增湿有助于增强深对流加热，驱动更强的强迫开尔文波样扰动。这加强了低层的摩擦辐合，导致更大的浅层对流加热，因此在MJO的深对流的发展和增强更快。
Global warming's impact on the Madden-Julian Oscillation (MJO) is assessed using one of the few models capable in reproducing its key features. In a warmer climate predicted for the end of the century, the MJO increases in amplitude (by similar to 30%) and frequency, showing a more circumglobal propagation tendency. The MJO spatial extent becomes enhanced, deeper, and more zonally extended but meridionally confined. A stronger vertical tilting structure in diabatic heating, moisture, and convergence fields is seen. Our findings indicate that these changes result from an intensification of the frictional wave-conditional instability of the second kind mechanism via the coupling of dynamical and thermodynamic response to the warming. The warming and moistening of the mean state contribute to the enhanced deep convective heating, driving a stronger-forced Kelvin wave-like perturbation. This reinforces the frictional low-level convergence, leading to larger shallow convective heating and therefore to a faster development and enhancement of the deep convection in the MJO.