UMBRELLA - UM Boundary Layer Representation including land-atmosphere interactions

UMBRELLA - UM 边界层表示，包括陆地-大气相互作用

• 批准号: NE/X018555/1
• 负责人: Andrew Ross
• 金额: $ 97.91万
• 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: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX018555%2F1
• 关键词: UMBRELLA; UM; Boundary; Layer; Representation

The atmospheric boundary layer (BL) is the layer of the atmosphere near the Earth's surface which is directly influenced by the surface. The BL plays a key role in the atmosphere - controlling the exchange of heat, moisture and other atmospheric constituents (both natural and anthropogenic) between the surface and the free troposphere. The boundary layer is also crucial in the initiation of convection and so impacts on the location and timing of convective rainfall. Turbulence is a key characteristic of the BL but is generally too small scale to be resolved in weather and climate models and so needs to be parametrised. With increased computational resources it is now feasible to run operation weather forecasts at km scales where convection can be resolved explicitly (though not necessarily well resolved). As we move towards sub-km scale the models will also begin to resolve large scale boundary structures. This regime where we partly resolve these key processes is known as the grey zone. Modelling the boundary layer in the grey zone requires re-evaluation and modification of the boundary layer parametrisation schemes and their coupling to convection (parametrised or explicit). This project will firstly evaluate the currently available boundary layer schemes and their coupling to convection in the Met Office Unified Model (MetUM) at different resolutions across the grey zone as well as testing any new developments produced as part of this programme. Secondly it will study the coupling between surface heterogeneity, boundary layer structures and convection to understand the key role of heterogeneity. Previous studies largely focus on homogeneous case studies, despite the fact that most land is actually not flat and covers a variety of land use and surface conditions. Including surface heterogeneity will allow a more thorough evaluation of the current boundary layer schemes as well as providing a physical underpinning for more realistic parametrisations which are aware of the underlying variability in the surface characteristics. The project will make use of the latest field observations from the upcoming Wescon field campaign as well as data from long term observational sites in the UK and US. We will also utilise the latest Meteosat third generation satellite observations to evaluate the model in the tropics. We will combine these observations with idealised large eddy simulations and more realistic simulations with the MetUM to study the behaviour of the boundary layer over the diurnal cycle at homogeneous sites and for heterogeneous regions (e.g. regions with variable surface temperature and moisture, or gentle topography).

大气边界层（BL）是地球表面附近的大气层，直接受表面影响。 BL在大气中起着关键作用 - 控制着表面和自由对流层之间的热，水分和其他大气成分（自然和人为成分）的交换。边界层对于对流的启动也至关重要，因此对对流降雨的位置和时机产生影响。湍流是BL的关键特征，但规模通常太小，无法在天气和气候模型中解决，因此需要进行参数化。随着计算资源的增加，现在可以在可以明确解决对流的KM量表上运行操作天气预报（尽管不一定能很好地解决）。当我们朝着亚公里尺度迈进时，模型还将开始解决大规模边界结构。我们部分解决这些关键过程的这种制度称为灰色区域。在灰色区域建模边界层需要重新评估和修改边界层参数化方案及其耦合到对流（参数化或显式）。该项目将首先评估当前可用的边界层方案及其耦合，以在整个灰色区域的不同分辨率的MET办公室统一模型（Metum）中进行对流，并测试作为该计划的任何新开发项目。其次，它将研究表面异质性，边界层结构和对流之间的耦合，以了解异质性的关键作用。尽管大多数土地实际上并不平坦，并且涵盖了各种土地使用和表面条件，但先前的研究主要集中在均匀的案例研究上。包括表面异质性将允许对当前边界层方案进行更彻底的评估，并为更现实的参数提供物理基础，这些参数意识到表面特征的潜在可变性。该项目将利用即将推出的WESCON现场活动的最新现场观察以及英国和美国的长期观察站点的数据。我们还将利用最新的MeteoSat第三代卫星观测值来评估热带地区的模型。我们将将这些观察结果与理想化的大型涡流模拟和更真实的模拟与元素结合起来，以研究均匀位点和异质区域（例如具有可变的表面温度和水分和温和特形的区域）的边界层的行为。