Thermodynamic Bias in the Multimodel Mean Boreal Summer Monsoon
Thermodynamic Bias in the Multimodel Mean Boreal Summer Monsoon
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DOI：
10.1175/jcli-d-12-00493.1
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发表时间：
2013-04
影响因子：
4.9
通讯作者：
W. Boos;J. Hurley
中科院分区：
文献类型：
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作者：
W. Boos;J. Hurley
本文表明，几乎所有参加耦合模式比对计划（CMIP）的模式在北半球夏季风的热力结构上都表现出共同的偏差。最强的偏差位于南亚，那里的对流层上层温度最高值太弱，被转移到其观测位置的东南方向，并没有像观测中那样向西延伸到非洲。模拟的亚洲地面空气湿静态能量的最大值也太弱，位于沿海海洋，而不是在其观察到的大陆位置。这种偏差的空间结构表明，它是由青藏高原以西的地形过于平滑的表现造成的，这使得来自西亚沙漠的干燥空气能够穿透季风热峰，抑制潮湿对流并冷却对流层上层。在一个能较好地反映亚洲季风热力状态的气候模式中，这一B的定性特征是不确定的。
AbstractHere it is shown that almost all models participating in the Coupled Model Intercomparison Project (CMIP) exhibit a common bias in the thermodynamic structure of boreal summer monsoons. The strongest bias lies over South Asia, where the upper-tropospheric temperature maximum is too weak, is shifted southeast of its observed location, and does not extend as far west over Africa as it does in observations. Simulated Asian maxima of surface air moist static energy are also too weak and are located over coastal oceans rather than in their observed continental position. The spatial structure of this bias suggests that it is caused by an overly smoothed representation of topography west of the Tibetan Plateau, which allows dry air from the deserts of western Asia to penetrate the monsoon thermal maximum, suppressing moist convection and cooling the upper troposphere. In a climate model with a decent representation of the thermodynamic state of the Asian monsoon, the qualitative characteristics of this b...