DCMEX: The Deep Convective Microphysics EXperiment

DCMEX：深对流微物理实验

• 批准号: NE/T006439/1
• 负责人: Martin Gallagher
• 金额: $ 138.43万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FT006439%2F1
• 关键词: DCMEX; Deep; Convective; Microphysics; EXperiment

The goal of the DCMEX project is to ultimately reduce the uncertainty in equilibrium climate sensitivity by improving the representation of microphysical processes in global models. It is the anvils produced by tropical systems in particular that contribute significantly to cloud feedbacks. The anvil radiative properties, lifetimes and areal extent are the key parameters. DCMEX will determine the extent to which these are influenced, or even controlled by the cloud microphysics including the habits, concentrations and sizes of the ice particles that make up the anvils, which in turn depend on the microphysical processes in the mixed-phase region of the cloud as well as those occurring in the anvil itself.There has been a rapid advancement in the sophistication of global climate models in recent years. Yet some of the equations used to represent microphysics processes are based on a poorer physical understanding than desired. Gettelman and Sherwood (2016), for example pointed out that there is significant spread in determining cloud feedbacks across different global models due to uncertainties in microphysical processes, such as the treatment of ice processes. Ceppi et al. (2017) also concluded that accurately representing clouds and their radiative effects in global models remains challenging partly due to the difficulty in representing the cloud microphysics, as well as the interactions between microphysics and dynamics. The microphysical and radiative processes and dynamics that control the opacity and areal coverage of tropical anvil clouds are not well represented in global climate models.DCMEX will make novel measurements of cloud microphysics in a real-world laboratory convective cloud system - both the mixed-phase region and anvil - as well as improve and test models and then apply them globally to tropical deep convective systems. We propose to deploy the FAAM aircraft along with two dual-polarisation, Doppler radars and airborne and ground-based aerosol measurements to study the deep convective clouds that form over an isolated mountain range in New Mexico. The focus will be on the formation of ice from ice nucleating particles (INPs) (primary ice production) and by processes involving existing ice particles (secondary ice particle production), such as collisions. These observations will be used to test and further refine the representation of ice processes in climate models. Our approach recognises that in order to represent cloud feedbacks accurately a model needs to represent the individual processes within the system accurately. Demonstrating that the model is able reproduce the observed evolution of these clouds is therefore a necessary condition for the accurate prediction of cloud feedbacks.The research in DCMEX will have a robust pathway from a novel field campaign to more accurate estimates of climate sensitivity. This pathway is built with four integrated parts: new observations; the use of these observations and process modelling to derive new parametrisations; the use of existing in-situ data and satellite observations of anvils in tropical deep convection to validate the model; and use of the knowledge gained to improve and test the representation of microphysics in climate models. In particular, DCMEX will build on the experience of our groups in improving microphysical representation. A seamless suite of Met Office models will be used for convection- resolving simulations and global simulations with parametrised convection. Finally, simplified climate change (imposed warmer environment) experiments will be carried out to understand the role of the different microphysical processes on cloud feedbacks.

DCMEX项目的目标是通过改善全球模式中微物理过程的表现，最终减少平衡气候敏感性的不确定性。特别是热带系统产生的铁砧对云的反馈有很大的贡献。对顶辐射特性、寿命和面积是关键参数。DCMEX将确定这些受云微物理学影响甚至控制的程度，包括构成铁砧的冰粒的习性、浓度和大小，而这些又取决于云混合相区以及铁砧本身发生的微物理过程。近年来，全球气候模式的复杂性有了迅速的发展。然而，一些用于表示微观物理过程的方程是基于比预期更差的物理理解。例如，Gettelman和舍伍德（2016）指出，由于微物理过程（如冰过程的处理）的不确定性，在确定不同全球模型的云反馈方面存在显著差异。Ceppi et al.（2017）还得出结论，在全球模型中准确地表示云及其辐射效应仍然具有挑战性，部分原因是难以表示云的微物理学，以及微物理学和动力学之间的相互作用。控制热带砧云的不透明度和面积覆盖的微物理和辐射过程和动力学在全球气候模式中没有得到很好的体现，DCMEX将在真实世界的实验室对流云系统中对云微物理进行新的测量-混合相区和砧-以及改进和测试模型，然后将其应用于全球热带深对流系统。我们建议部署的FAAM飞机沿着与两个双极化，多普勒雷达和机载和地面气溶胶测量研究深对流云，形成在新墨西哥州的一个孤立的山脉。重点将放在冰成核颗粒（INPs）（初级冰生产）和涉及现有冰粒的过程（次级冰粒生产），如碰撞。这些观测结果将用于测试和进一步完善气候模型中冰过程的代表性。我们的方法认识到，为了准确地表示云反馈，模型需要准确地表示系统中的各个过程。因此，证明该模型能够再现观测到的这些云的演变是准确预测云反馈的必要条件。DCMEX的研究将有一个强大的途径，从一个新的现场活动到更准确的气候敏感性估计。这条途径由四个组成部分组成：新的观测;利用这些观测和过程建模来推导新的参数化;利用现有的热带深对流中砧座的原位数据和卫星观测来验证模型;利用所获得的知识来改进和测试气候模型中微观物理学的代表性。特别是，DCMEX将建立在我们的团队在改善微物理表现的经验。一套无缝的气象局模型将用于对流解析模拟和参数化对流的全球模拟。最后，将进行简化的气候变化（强加的更温暖的环境）实验，以了解不同的微物理过程对云反馈的作用。

项目成果

DCMEX coordinated aircraft and ground observations: Microphysics, aerosol and dynamics during cumulonimbus development

DCMEX 协调飞机和地面观测：积雨云发展过程中的微物理、气溶胶和动力学

• DOI: 10.5194/essd-2023-303
• 发表时间: 2023
• 作者: Finney D