EUREC4A-UK: Elucidating the role of cloud-circulation coupling in climate

EUREC4A-UK：阐明云-环流耦合在气候中的作用

• 批准号: NE/S015868/1
• 负责人: Alan Blyth
• 金额: $ 183.88万
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FS015868%2F1
• 关键词: EUREC4A; UK; Elucidating; role; cloud

EUREC4A-UK is a programme of observational and modelling research which aimsto study the detailed aerosol and cloud processes in the life cycle of shallow tradecumulus clouds and the two-way interactions between the cloud processes and thelarge-scale dynamics. The different responses of these clouds to warming in globalclimate models (GCM) explain most of the inter-model differences, yet the physicsof these responses remains poorly constrained. The programme is focussed onthe participation of UK scientists and the BAS Twin Otter aircraft in EUREC4A(Elucidating the Role of Clouds-Circulation Coupling in Climate). EUREC4A isa coordinated international campaign that aims to address the current lack of understanding ofthe processes controlling the response of trade-wind cumulus clouds to changing environmentalconditions in a warmer climate. The goal of EUREC4A is to examine the interplay between theclouds, atmospheric circulations and climate sensitivity. EUREC4A-UK will make a unique and self-contained contribution to the international programme by: (i) providing observational facilities whichare needed as part of the coordinated field campaign; (ii) conducting and leading the analysis ofthe aerosols, cloud microphysics and boundary-layer processes in the life cycle of shallow tradecumulus clouds; (iii) placing the analysis in the context of the EUREC4A problems by modelling thetwo-way interactions between the cloud processes and the large-scale dynamics; and (iv) applyingthe results by testing the new convection scheme in the UM and using the improved model to determinethe dominant processes controlling the cloud fields. International partners will complement the re-search with a focus on observing and modelling the macrophysical properties and the environmentof trade-cumulus clouds in order to determine: (i) what controls the convective mass flux, mesoscaleorganization and depth of shallow-cumulus clouds; (ii) how the trade-cumulus cloud fraction varieswith turbulence, convective mixing and large-scale circulations; and (iii) the impact this variation hason atmospheric radiation.The radiative properties of the trade-wind cumulus clouds that are ubiquitous over the tropical oceans have a major influence on the Earth's radiation budget. The response to global warming of these clouds is therefore critical for global mean cloud feedbacks. It is the differing response to warming that explains most of the spread of climate sensitivity in climate models. Hence, a better understanding is required of the mechanisms that control the low-level cloud fraction. The urgency of the research is made clear by the fact that the World Climate Research Programme endorses the EUREC4A field project which supports the Grand Challenge on Clouds, Circulation and Climate Sensitivity.There is a clear need for EUREC4A-UK because the aerosol,cloud and precipitation processes influence the macrophysical properties of the clouds in differentenvironments. For example, the vertical distribution of raincan affect the concentration and size of cloud drops in the upper detrainment layers, which influ-ences cloud radiative properties. The intensity of rain and evaporation of raindrops influences thestrength of gust fronts and hence secondary cloud-production. However, model calculations of therate of production of rain and hence the quantity of rain are uncertain due to the complex interactionsof aerosols, entrainment, turbulence and giant cloud condensation nuclei (GCCN). These processesdepend on the environment conditions, controlled by the large-scale dynamics. Equally, the aerosol-cloud-precipitation processes can influence the larger-scale dynamics, for example through radiativetransfer. Indeed there are many interactions between processes on a range of scales that need to beunderstood and represented in models.

EUREC 4A-UK是一个观测和模拟研究方案，目的是研究浅对流云生命周期中详细的气溶胶和云过程以及云过程和大尺度动力学之间的双向相互作用。这些云在全球气候模式（GCM）中对变暖的不同反应解释了大部分模式间的差异，但这些反应的物理学仍然缺乏约束。该计划的重点是英国科学家和BAS Twin Otter飞机参与EUREC 4A（阐明云-环流耦合在气候中的作用）。EUREC 4A伊萨一个协调的国际运动，旨在解决目前缺乏了解的过程控制贸易风积云的反应，以改变环境条件，在温暖的气候。EUREC 4A的目标是研究云、大气环流和气候敏感性之间的相互作用。联合王国EUREC 4A将通过以下方式对国际方案作出独特和自足的贡献：（一）提供作为协调实地活动一部分所需的观测设施;（二）进行并领导对浅层对流云生命周期中的气溶胶、云微物理学和边界层过程的分析;（iii）通过模拟云过程和大尺度动力学之间的双向相互作用，将分析置于EUREC 4A问题的背景下;（iv）在UM中对新的对流方案进行试验，并利用改进的模式确定控制云场的主导过程。国际合作伙伴将补充这项研究，重点是观测信风积云的宏观物理特性和环境并建立模型，以便确定：（一）是什么控制着对流质量通量、中尺度组织和浅积云的深度;（二）信风积云的比例如何随湍流、对流混合和大尺度环流而变化;热带海洋信风积云的辐射特性对地球辐射收支有重要影响。因此，这些云对全球变暖的反应对于全球平均云反馈至关重要。正是对变暖的不同反应解释了气候模型中气候敏感性的大部分传播。因此，需要更好地了解控制低层云分数的机制。世界气候研究计划批准了支持云、环流和气候敏感性大挑战的EUREC 4A实地项目，这一事实清楚地表明了研究的紧迫性。例如，降水的垂直分布可以影响到上平流层中云滴的浓度和大小，从而影响云的辐射特性。雨强和雨滴蒸发影响阵风锋的强度，从而影响二次云的产生。然而，由于气溶胶、卷吸、湍流和巨云凝结核（GCCN）的复杂相互作用，模式计算的降雨产生率和降雨量是不确定的。这些过程依赖于环境条件，受大尺度动力学控制。同样，气溶胶-云-降水过程也可以影响大尺度的动力学，例如通过辐射传输。事实上，在一系列尺度上的过程之间存在许多相互作用，需要在模型中加以理解和表示。

项目成果

Driving a Convection Parametrization with EUREC4A Observations

利用 EUREC4A 观测推动对流参数化

• DOI: 10.5194/egusphere-egu21-14886
• 发表时间: 2021
• 作者: Saffin L

Clouds and Aerosols observed during EUREC4A by the UK Twin Otter aircraft.

英国双水獭飞机在 EUREC4A 期间观测到的云和气溶胶。

• DOI: 10.5194/egusphere-egu2020-3667
• 发表时间: 2020
• 作者: Lachlan-Cope T

Life cycle of a flower cloud system during the EUREC 4 A field campaign

EUREC 4 A 现场活动期间花卉云系统的生命周期

• DOI: 10.5194/egusphere-2023-1999
• 发表时间: 2023
• 作者: Cui Z

EUREC<sup>4</sup>A

欧洲经济合作委员会

• DOI: 10.5194/essd-2021-18
• 发表时间: 2021
• 作者: Stevens B

Charting the Realms of Mesoscale Cloud Organisation using Unsupervised Learning

使用无监督学习绘制中尺度云组织的领域

• DOI: 10.48550/arxiv.2309.08567
• 发表时间: 2023
• 作者: Denby L