A Test of Emergent Constraints on Cloud Feedback and Climate Sensitivity Using a Calibrated Single-Model Ensemble
A Test of Emergent Constraints on Cloud Feedback and Climate Sensitivity Using a Calibrated Single-Model Ensemble
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使用校准的单模型集合测试云反馈和气候敏感性的紧急约束
DOI：
10.1175/jcli-d-17-0682.1
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发表时间：
2018
影响因子：
4.9
通讯作者：
C. Jackson
中科院分区：
文献类型：
--
作者：
B. Wagman;C. Jackson
一个校准的单一模式集合（SME）来自NCAR社区大气模式，版本3.1，被用来测试两个假设的云反馈和平衡气候敏感性（ECS）的紧急约束。计算了SME现今气候的Fasullo和Trenberth相对湿度（RH）度量和舍伍德等人的低对流层混合（LTMI）度量，并研究了这些度量、ECS、云和其他气候反馈之间的关系。热带辐合区相对湿度（RH M）和参数化低对流层混合（LTMI S）的ECS呈正相关，并与不同的空间格局的热带短波云反馈中小企业。然而，这两个指标都与作者假设的云响应类型无关。解决低对流层混合（LTMI D）是正相关的ECS的一个子集的SME具有LTMI D超过阈值。LTMI和RH的干，下降分支的Hadley细胞（RH D）缩小和移动后的估计ECS在SME，但SME的RH D和关注的偏差不甚了解的物理机制表明，缩小可能是虚假的两个约束。虽然校准的SME结果可能不会推广到多模型集成，但它们可以增强对紧急约束的过程理解，并作为鲁棒性的样本外测试。
A calibrated single-model ensemble (SME) derived from the NCAR Community Atmosphere Model, version 3.1, is used to test two hypothesized emergent constraints on cloud feedback and equilibrium climate sensitivity (ECS). The Fasullo and Trenberth relative humidity (RH) metric and the Sherwood et al. lower-tropospheric mixing (LTMI) metric are computed for the present-day climate of the SME, and the relationships between the metrics, ECS, and cloud and other climate feedbacks are examined. The tropical convergence zone relative humidity (RH M) and the parameterized lower-tropospheric mixing (LTMI S) are positively correlated to ECS, and each is associated with a different spatial pattern of tropical shortwave cloud feedback in the SME. However, neither of those metrics is linked to the type of cloud response hypothesized by its authors. The resolved lower-tropospheric mixing (LTMI D) is positively correlated to ECS for a subset of the SME having LTMI D over a threshold value. LTMI and the RH for the dry, descending branch of the Hadley cell (RH D) narrow and shift upward the posterior estimates of ECS in the SME, but the SME bias in RH D and concerns over poorly understood physical mechanisms suggest the narrowing could be spurious for both constraints. While calibrated SME results may not generalize to multimodel ensembles, they can enhance the process understanding of emergent constraints and serve as out-of-sample tests of robustness.
影响因子：
4.9
作者：
D. Klocke;R. Pincus;J. Quaas
通讯作者：
D. Klocke;R. Pincus;J. Quaas