The configuration of the Met Office Unified Model being submitted to CMIP6 has a high climate sensitivity. Previous studies have suggested that the impact of model changes on initial tendencies in numerical weather prediction (NWP) should be used to guide their suitability for inclusion in climate models. In this study we assess, using NWP experiments, the atmospheric model changes which lead to the increased climate sensitivity in the CMIP6 configuration, namely, the replacement of the aerosol scheme with GLOMAP‐mode and the introduction of a scheme for representing the turbulent production of liquid water within mixed‐phase cloud. Overall, the changes included in this latest configuration were found to improve the initial tendencies of the model state variables over the first 6 hr of the forecast, this timescale being before significant dynamical feedbacks are likely to occur. The reduced model drift through the forecast appears to be the result of increased cloud liquid water, leading to enhanced radiative cooling from cloud top and contributing to a stronger shortwave cloud radiative effect. These changes improve the 5‐day forecast in traditional metrics used for numerical weather prediction. This study was conducted after the model was frozen and the climate sensitivity of the model determined; hence, it provides an independent test of the model changes contributing to the higher climate sensitivity. The results, along with the large body process‐orientated evaluation conducted during the model development process, provide reassurance that these changes are improving the physical processes simulated by the model.

中文翻译：

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使用短期预报来评估与气候敏感性相关的快速物理过程

提交给CMIP6的Met Office统一模型的配置具有很高的气候敏感性。先前的研究表明，应使用模型变化对数值天气预报（NWP）初始趋势的影响来指导其是否适合纳入气候模型。在这项研究中，我们使用NWP实验评估了大气模型的变化，该变化导致了CMIP6配置中气候敏感性的提高，即用GLOMAP模式替代了气溶胶方案，并引入了代表湍流产生的方案。混合相云中的液态水。总体而言，发现此最新配置中包含的更改可改善预测的前6小时内模型状态变量的初始趋势，这个时间范围是在可能发生重大动态反馈之前。通过预测得出的模型漂移减少似乎是云液态水增加的结果，导致云顶辐射冷却增强，并导致更强的短波云辐射效应。这些更改改进了用于数值天气预报的传统指标中的5天预报。在冻结模型并确定模型的气候敏感性之后进行了这项研究。因此，它提供了对模型变化的独立测试，从而有助于提高气候敏感性。结果以及在模型开发过程中进行的以大型车身过程为导向的评估，可以确保这些变化正在改善模型所模拟的物理过程。