Mechanisms of tropical precipitation biases in climate models
Mechanisms of tropical precipitation biases in climate models
复制标题
DOI：
10.1007/s00382-020-05325-z
复制
发表时间：
2020-10
期刊：
影响因子：
4.6
通讯作者：
Hanjun Kim;Sarah M. Kang;Ken Takahashi;A. Donohoe;A. Pendergrass
中科院分区：
文献类型：
--
作者：
Hanjun Kim;Sarah M. Kang;Ken Takahashi;A. Donohoe;A. Pendergrass
通过经验正交函数分析，探讨了热带纬向平均降水模式的模式间传播的可能原因。对称型是主要模态的特征，与最大降水位置的季节振幅密切相关。能量约束将对称模式与跨赤道大气能量输送的季节振幅和年平均赤道净能量输入联系起来。对能量学变量的分解表明，对称降水模式的模式间传播与晴空大气短波吸收模式间传播相关，这很可能是由于辐射传输参数化的差异造成的，而不是水汽模式的差异。其中对称降水模式的模式间传播主要与赤道地区净地表能通量的模式间传播有关，并受赤道上升流冷却强度的调制。研究结果为理解热带降水偏倚的机制提供了线索，从而为模式改进提供了指导。
We investigate the possible causes for inter-model spread in tropical zonal-mean precipitation pattern, which is divided into hemispherically symmetric and anti-symmetric modes via empirical orthogonal function analysis. The symmetric pattern characterizes the leading mode and is tightly related to the seasonal amplitude of maximum precipitation position. The energetic constraints link the symmetric pattern to the seasonal amplitude in cross-equatorial atmospheric energy transportand the annual-mean equatorial net energy input. Decomposition ofinto the energetics variables indicates that the inter-model spread in symmetric precipitation pattern is correlated with the inter-model spread in clear-sky atmospheric shortwave absorption, which most likely arises due to differences in radiative transfer parameterizations rather than water vapor patterns. Among the components that consist, the inter-model spread in symmetric precipitation pattern is mostly associated with the inter-model spread in net surface energy flux in the equatorial region, which is modulated by the strength of cooling by equatorial upwelling. Our results provide clues to understand the mechanism of tropical precipitation bias, thereby providing guidance for model improvements.