Understanding and Modelling Natural and Forced Variability of Near-Surface Winds

理解近地表风的自然变化和受迫变化并对其进行建模

• 批准号: RGPIN-2019-04986
• 负责人: Monahan, Adam
• 金额: $ 3.72万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=750981
• 关键词: Understanding; Modelling; Natural; Forced; Variability

Near-surface winds control the exchange of mass, energy, and momentum between the atmosphere and the underlying surface; they influence surface temperature and air quality and represent an energy resource of growing importance; and their extremes represent hazards to the natural and built environments. The proposed research is comprised of four complimentary wind-related research projects addressing urgent questions in the field. Future climate changes will be associated with changes in wind and solar energy (as well as of their co-variability which can mitigate the intermittency of renewables). In the first project, we will use ensembles of climate model simulations to quantify uncertainties related to North American renewable energy in the 21st century. We will also relate interannual and interdecadal variability in power resources to dominant modes of climate variability such as El Nino. Near-surface wind speed is determined by processes across the Planetary Boundary Layer (PBL). The nocturnal PBL displays two regimes, with very different temperature and wind profiles. These structures are poorly represented in weather and climate models, resulting in temperature and wind biases. The second project will apply novel mathematical tools to idealized physical models to investigate these regimes. We will then consider the role of irregular weather variations in driving regime transitions. Extremes of sea surface wind components are substantially affected by asymmetries in their fluctuations around the mean. I have developed a set of idealized models to account for this behaviour. A novel perspective on the physical origin of these asymmetries is provided by the bispectrum, which partitions this asymmetry into different frequency contributions. In the third project, we will use bispectra to further investigate the physics of wind component fluctuation asymmetry in observations and in an idealized model. Air-sea exchanges in weather and climate models depend on wind speed. Small-scale winds not resolved in these models contribute to flux enhancements that the models must parameterize. While parameterizations normally assign a unique subgrid-scale flux to each unique state of the resolved flow, we have shown that in fact these corrections are better represented by probability distributions. The fourth project will extend our earlier analysis to longer records and larger domains, with the goal of implementing such a parameterization in an operational weather model.

近地表风控制大气和下面表面之间的质量，能量和动量的交换；它们会影响表面温度和空气质量，并代表着日益重要的能源；它们的极端是对自然和建筑环境的危害。拟议的研究由四个免费的风向研究项目组成，这些研究项目解决了该领域的紧急问题。未来的气候变化将与风能和太阳能的变化有关（以及它们的共同可变性，可以减轻可再生能源的间歇性）。在第一个项目中，我们将使用气候模型模拟集合来量化与21世纪北美可再生能源有关的不确定性。我们还将将电力资源中的年际和跨年龄变化与诸如El Nino之类的气候变异性模式联系起来。近地表风速取决于行星边界层（PBL）的过程。夜间PBL显示了两个机制，温度和风轮廓非常不同。这些结构在天气和气候模型中的代表性很差，导致温度和风偏见。第二个项目将将新颖的数学工具应用于理想化的物理模型以研究这些制度。然后，我们将考虑不规则天气变化在驾驶制度转变中的作用。海面风组分的极端情况在于平均值周围的波动中受到了不对称的影响。我已经开发了一组理想化的模型来说明这一行为。双光谱提供了对这些不对称性的物理起源的新观点，该观点将这种不对称性分为不同的频率贡献。在第三个项目中，我们将使用Bispectra进一步研究了观测和理想化模型中风力成分不对称性的物理。 天气和气候模型中的空气交换取决于风速。在这些模型中未解决的小规模风导致模型必须参数化的通量增强。虽然参数化通常为解决流的每个唯一状态分配唯一的子网格尺度通量，但实际上，这些校正实际上是由概率分布更好地表示的。第四个项目将把我们的早期分析扩展到更长的记录和较大的域，其目的是在操作天气模型中实施这种参数化。