CIRCULATES - Circulation, Clouds and Climate Sensitivity

气候模型是用于预测未来气候变化的数值模型。由于计算能力的限制，需要对模型的某些部分进行近似，特别是在发生重要过程的小尺度上，这些过程比在其上进行计算的模型网格小。目前尚不清楚如何最好地近似小规模过程，因此，不同的GCM使用不同的近似，并产生对未来气候变化的不同预测。这些不确定性中最重要的一个是云层的低密度，这也是循环方案的重点。我们现在可以获得新的、高分辨率的卫星观测，我们可以用来建立数据集，让我们更好地了解云是如何形成和扩散的，以及它们是如何与它们所处的环境相互作用的。我们也有高分辨率的建模工具，能够以更高的精度模拟云所需的物理过程。高分辨率模型的计算成本太高，无法在全球范围内运行许多个模型年，而这种运行方式可以直接用于预测气候变化。然而，结合卫星数据，它们可以用来确定在GCM模型网格上表示云的效果的最佳方式。这些信息可以传输到气候模型，然后可以运行该模型来发现我们的发现对全球气候变化的影响。在《循环》中，我们建议开发新的卫星数据和高分辨率模拟，以帮助改进和理解气候模型的反应，重点放在热带和亚热带云上。该项目旨在通过两种方式帮助气候科学界和政策界。首先，我们的发现将用于评估由世界各地的建模中心为政府间气候变化专门委员会(IPCC)报告运行的气候模型所做的模拟。目前，IPCC GCM在代表云流程方面做得如何？对于未来的模拟，它们的表现形式是如何变化的，这是否合适？通过确定模拟与高分辨率卫星和模型数据相比的保真度，我们将确定模型模拟的可信程度，目的是限制未来气候变化的可能范围。其次，我们将开发不仅对约束预测而且对构建下一代模型的模型开发人员有用的度量标准。我们的项目与英国气象局有很强的合作，后者与学术界一起，是英国用于理解气候变化的模型的主要开发者。我们将定期与英国气象局和UKESM的主要工作人员接触，以确定如何使我们的结果对模型开发最有用。

Climate models are numerical models used to make projections of future climate change. Because of limitations in computing power, approximations to some parts of the model are required, particularly on small scales where important processes occur that are smaller than the model grid on which calculations are carried out. It is not clear how best to approximate small-scale processes and as a result, different GCMs use different approximations and produce different predictions of future climate change. One of the most important of these uncertainties is how low clouds are represented, and that is the focus of the CIRCULATES proposal.We now have access to new, high resolution satellite observations that we can use to build datasets that give us a much better idea of how clouds form and disperse, and how they interact with the environment in which they find themselves. We also have high resolution modelling tools that are able to represent the physical processes necessary to simulate clouds with much higher accuracy. High resolution models are far too computationally expensive to run for many model years over the whole globe in a way that could be used to project changes in climate directly. However, in conjunction with the satellite data, they can be used to determine the best way to represent the effects of clouds on the GCM model grid. This information can be transferred to the climate model, which can then be run to discover the impact of our findings on global climate change. In CIRCULATES, we propose to develop both new satellite data and high resolution simulations that are specifically designed to assist with improving and understanding the response of climate models with a focus on tropical and sub-tropical clouds.The project aims to assist the climate science and policy communities in two ways. First, the discoveries that we make will be used to assess the simulations made by climate models run by modelling centres around the world for the Intergovernmental Panel on Climate Change (IPCC) reports. How well are IPCC GCMs representing cloud processes in the present day? How does their representation change for simulations of the future and is this appropriate? By determining the fidelity of simulation in comparison with high resolution satellite and model data, we will determine the extent to which model simulations can be trusted, with the aim of constraining the likely range of future climate change. Second, we will develop metrics that are useful not only for constraining projections but also for model developers who are building the next generation of models. Our project has strong collaboration with the Met Office, who, together with the academic community, are the primary developers of models used for understanding climate change in the UK. We will engage with key Met Office and UKESM staff on a regular basis in order to determine how our results may be made most useful to model development.