Sensitivity of tropical intraseasonal variability to the pattern of climate warming
Sensitivity of tropical intraseasonal variability to the pattern of climate warming
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DOI：
10.1029/2012ms000171
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发表时间：
2013-03
影响因子：
6.8
通讯作者：
E. Maloney;S. Xie
中科院分区：
文献类型：
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作者：
E. Maloney;S. Xie
利用一个水行星环流模式研究了季节内变率对海表温度（SST）增暖的敏感性。使用了三种加热模式。地球物理流体动力学实验室气候模式2.1预测的世纪末SST变暖是一种模式，另外两种模式是具有相同全球平均SST变化的纬向对称和全球均匀版本的变暖扰动。季节内变率的变化对SST变暖的模式很敏感，对于纬向对称变暖，Madden-Julian振荡（MJO）时间尺度降水和风变率显着减少，而对于全球均匀变暖，MJO降水幅度显着增加。风变率变化的幅度并不直接与降水成比例，而是通过与SST变暖相关的热带干静态稳定性增加来介导的。模式化SST模拟具有赤道上最大化的纬向平均SST变暖，这促进了赤道边界层辐合的增加，并且相对于热带其他地区也增加了赤道SST。这两个因素都支持对流增加，反映在总湿稳定性（GMS）降低。在模式化变暖模拟中，在10°S附近的赤道外东半球，平均降水量减少，GMS增加，其中最强的MJO相关的季节内降水变率在模型和观测中都是首选的。有人认为，未来的MJO活动的变化可能是敏感的SST变暖的模式，虽然这些结果不应该被解释为预测MJO活动将如何在未来的气候变化。
An aquaplanet general circulation model is used to assess the sensitivity of intraseasonal variability to the pattern of sea surface temperature (SST) warming. Three warming patterns are used. Projected SST warming at the end of the 21st century from the Geophysical Fluid Dynamics Laboratory Climate Model 2.1 is one pattern, and zonally symmetric and globally uniform versions of this warming perturbation that have the same global mean SST change are the other two. Changes in intraseasonal variability are sensitive to the pattern of SST warming, with significant decreases in Madden‐Julian oscillation (MJO)‐timescale precipitation and wind variability for a zonally symmetric warming, and significant increases in MJO precipitation amplitude for a globally uniform warming. The amplitude of the wind variability change does not scale directly with precipitation, but is instead mediated by increased tropical dry static stability associated with SST warming. The patterned SST simulations have a zonal mean SST warming that maximizes on the equator, which fosters increased equatorial boundary layer convergence and also increases equatorial SST relative to the rest of the tropics. Both factors support increased convection, reflected in reduced gross moist stability (GMS). Mean precipitation is decreased and GMS is increased in the off‐equatorial Eastern Hemisphere near 10°S in the patterned warming simulations, where the strongest MJO‐related intraseasonal precipitation variability is preferred in both the model and observations. It is argued that future changes in MJO activity may be sensitive to the pattern of SST warming, although these results should not be interpreted as a prediction of how MJO activity will change in future climate.