GENESIS: Dynamics and parametrisation of deep convective triggering, maintenance and updraughts

GENESIS：深对流触发、维持和上升气流的动力学和参数化

• 批准号: NE/N013840/1
• 负责人: Douglas Parker
• 金额: $ 64.67万
• 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: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FN013840%2F1
• 关键词: GENESIS; Dynamics; parametrisation; deep; convective

Physically, deep convection is a key process in the atmosphere, particularly in the tropics, where it is the dominant driver of the weather as well as playing a key role in forcing global circulation. Despite this key role on the large scale, convection is inherently a relatively small-scale process with convective clouds typically being on the scale of 100's of metres to a few kms, and therefore unresolved in global numerical weather predicition (NWP) and climate models. "Parametrisation" of convection is therefore critical to accurately represent the impact of convection on the larger scale flow. This is not a simple problem, and deficiencies in current convective parametrisation schemes lead to significant model biases, the wrong diurnal cycle of convection in the tropics (with knock-on effects on rainfall and surface heating by radiation) and inadequate representation of important atmospheric circulations such as the Madden-Julien Oscillation, which are driven by convection. Two particular, and linked, problems which contribute to these deficiencies are the triggering of convection (timing, location and the stochastic nature of triggering) and the subsequent organisation of convection into larger convective systems.The overarching aim of this project is to bring together our understanding of the various physical processes which control the triggering and organisation of deep convection, and to use this to develop a framework in which these processes can be integrated in a consistent way. Such a framework will allow these important processes to be represented in new convective parametrisation schemes in a more physically realistic and consistent manner. In particular, a physically-based convective triggering scheme should be easier to integrate into the new generation of stochastic convective parametrisation schemes which are being developed. Such schemes will also be easier to make scale-aware, i.e. to adapt with the model resolution to only parametrise the necessary sub-grid processes, while allowing the model to resolve larger-scale features of the convection. This is particularly important for the latest NWP and regional climate model simulations which are of sufficiently high resolution that they permit the explicit representation of convection, albeit rather crudely. A further limitation of current parametrisation schemes is that they tend to be instantaneous. Where convection organised, the system has "memory", i.e. the occurrence and organisation of convection will impact on the local development of further convection. We will use techniques from other branches of fluid dynamics to understand and quantify organisation in convective systems and develop measures which can be used as the basis for new stochastic convection parametrisations.This project will consider both internal processes and external processes. Internal processes generated by the convection itself, such as gravity waves and cold pools, play a key role in the triggering and organisation of convection. Over land external factors such as surface heterogeneity and topography also play an important role in triggering convection and controlling how it can organise. Integrating these various competing influences into a consistent framework will be a significant step forward for parametrisation schemes. Having developed the framework from studying individual processes through idealised numerical simulations with the Met Office Unified Model (MetUM) and the Met Office-NERC cloud resolving model (MONC) we will test the ideas in more realistic large-domain simulations to help quantify the important scale interactions between small scale convection and the larger scale fields. The output of this project will be a series of generic physically-based model frameworks which can be used as components in different convective parametrisations schemes which are being proposed or developed, both within this programme and internationally

从物理上讲，深层对流是大气中的一个关键过程，特别是在热带地区，它是天气的主要驱动因素，并且在推动全球环流方面发挥着关键作用。尽管在大范围内发挥着关键作用，但对流本质上是一个相对小规模的过程，对流云的规模通常为数百米到几公里，因此在全球数值天气预报 (NWP) 和气候模型中尚未得到解决。因此，对流的“参数化”对于准确表示对流对更大规模流动的影响至关重要。这不是一个简单的问题，当前对流参数化方案的缺陷导致显着的模型偏差、热带地区对流的错误昼夜周期（对降雨和辐射导致的地表加热产生连锁反应）以及重要大气环流的不充分表征例如由对流驱动的马登-朱利安振荡。导致这些缺陷的两个特殊且相互关联的问题是对流的触发（触发的时间、位置和随机性质）以及对流随后组织成更大的对流系统。该项目的总体目标是将我们的了解控制深层对流的触发和组织的各种物理过程，并利用它来开发一个框架，在其中可以以一致的方式集成这些过程。这样的框架将使这些重要过程能够以更物理真实和一致的方式在新的对流参数化方案中表示。特别是，基于物理的对流触发方案应该更容易集成到正在开发的新一代随机对流参数化方案中。此类方案也将更容易实现尺度感知，即适应模型分辨率，仅参数化必要的子网格过程，同时允许模型解析对流的更大规模特征。这对于最新的数值天气预报和区域气候模型模拟尤其重要，这些模拟具有足够高的分辨率，可以明确地表示对流，尽管相当粗糙。当前参数化方案的进一步限制是它们往往是瞬时的。在对流组织的地方，系统具有“记忆”，即对流的发生和组织会影响局部对流的进一步发展。我们将使用流体动力学其他分支的技术来理解和量化对流系统中的组织，并开发可用作新随机对流参数化基础的措施。该项目将考虑内部过程和外部过程。对流本身产生的内部过程，如重力波和冷池，在对流的触发和组织中起着关键作用。在陆地上，表面异质性和地形等外部因素在引发对流和控制对流组织方式方面也发挥着重要作用。将这些不同的竞争影响整合到一个一致的框架中将是参数化方案向前迈出的重要一步。通过使用英国气象局统一模型 (MetUM) 和英国气象局-NERC 云解析模型 (MONC) 的理想化数值模拟研究各个过程，开发了一个框架，我们将在更现实的大域模拟中测试这些想法，以帮助量化重要的结果。小尺度对流和大尺度场之间的尺度相互作用。该项目的输出将是一系列基于物理的通用模型框架，可用作本计划和国际上正在提议或开发的不同对流参数化方案的组成部分

项目成果

Forced gravity waves and the tropospheric response to convection

受迫重力波和对流层对对流的响应

• DOI: 10.1002/qj.3278
• 发表时间: 2018-04-01
• 期刊: Quarterly Journal of the Royal Meteorological Society
• 影响因子: 8.9
• 作者: O. Halliday;S. Griffiths;D. Parker;A. Stirling;S. Vosper
• 通讯作者: S. Vosper

The Influence of the Diurnal Cycle in Wind Shear and Thermodynamics on Squall Lines in the West African Monsoon

风切变的昼夜循环和热力学对西非季风飑线的影响

• DOI: http://dx.10.1175/jas-d-21-0025.1
• 发表时间: 2022
• 期刊: Journal of the Atmospheric Sciences
• 影响因子: 3.1
• 作者: Bickle M

Analytical solution to a thermodynamic model for the sensitivity of afternoon deep convective initiation to the surface Bowen ratio

下午深对流引发对地表鲍文比敏感性热力学模型的解析解

• DOI: http://dx.10.1002/qj.3340
• 发表时间: 2018
• 期刊: Quarterly Journal of the Royal Meteorological Society
• 影响因子: 8.9
• 作者: Bhowmick M

Circling in on Convective Organization

围绕对流组织

• DOI: http://dx.10.1029/2019gl082092
• 发表时间: 2019
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Haerter J

An object-based model for convective cold pool dynamics

基于对象的对流冷池动力学模型

• DOI: http://dx.10.1515/mcwf-2016-0003
• 发表时间: 2016
• 期刊: Mathematics of Climate and Weather Forecasting
• 作者: Böing S