Understanding African Easterly Waves and their Predictability: a moist singular vector appraoch

了解非洲东风波及其可预测性：湿奇异矢量方法

• 批准号: NE/D010993/1
• 负责人: Brian Hoskins
• 金额: $ 28.83万
• 依托单位: University of Reading
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FD010993%2F1
• 关键词: Understanding; African; Easterly; Waves; their

The easterly waves that occur in West African summer monsoon are of vital importance to the region as the convective rainfall is mostly organised by them. The variability of this rainfall can have devastating impacts on the already vulnerable population. A small number of these weather systems transform downstream in the north Atlantic into hurricanes. However, despite the significance of these easterly waves, weather and climate models continue to have difficulties in predicting them and simulating the seasonal rainfall distribution in the region. A technique has been developed to find small changes to initial data, 'optimal perturbations', that produce the largest changes in the weather predicted in, for example, one day. This technique has been used to help understand the growth of high impact storms in middle latitudes. It is also the basis for a scheme that provides a range of slightly different initial conditions for a forecast system that produces an ensemble of weather forecasts. This ensemble gives indications of the probability of future weather events. Optimal perturbations are also used for giving indications of the sensitivity of tropical cyclone behaviour, but the technique has otherwise not been used for the tropics. In this project, a new version of the package to produce these optimal perturbations will be applied to the easterly waves in West Africa. It will be used to help the theoretical understanding of these systems. This will give a basis for using the important new observations that will be taken in 2006 in a series of international campaigns. It will also show how predictable African easterly waves are, including the convective rainfall they give and the likelihood that they will turn in to a hurricane. The project will provide a basis for weather forecast centres to construct an ensemble forecast system that is focussed initially on the tropics, but may also help in suggesting subsequent changes in middle latitudes.

西非夏季风中的东风波对该地区至关重要，因为对流降雨主要由它们组织。这种降雨的多变性可能对本已脆弱的人口产生破坏性影响。这些天气系统中的一小部分在北大西洋的下游转化为飓风。然而，尽管这些东风波的重要性，天气和气候模型仍然难以预测它们并模拟该地区的季节性降雨分布。已经开发出一种技术来寻找初始数据的微小变化，即“最佳扰动”，这种技术可以在一天内预测天气的最大变化。这项技术已被用来帮助了解中纬度地区高影响风暴的增长。它也是一个方案的基础，该方案为产生天气预报集合的预报系统提供一系列略有不同的初始条件。这个集合给出了未来天气事件概率的指示。最佳扰动也被用来显示热带气旋行为的敏感性，但该技术尚未用于热带地区。在这个项目中，一个新版本的包，以产生这些最佳的扰动将适用于在西非的东风波。这将有助于对这些系统的理论理解。这将为在一系列国际运动中使用2006年将获得的重要新观察结果奠定基础。它还将展示非洲东风波的可预测性，包括它们产生的对流降雨以及它们转变为飓风的可能性。该项目将为天气预报中心建立一个集合预报系统提供基础，该系统最初侧重于热带地区，但也可能有助于提示中纬度地区随后的变化。

项目成果

Convectively Coupled Equatorial Waves. Part I: Horizontal and Vertical Structures

对流耦合赤道波。

• DOI: 10.1175/jas4017.1
• 发表时间: 2007
• 期刊: Journal of the Atmospheric Sciences
• 影响因子: 3.1
• 作者: Yang G

Convectively Coupled Equatorial Waves. Part II: Propagation Characteristics

• DOI: 10.1175/jas4018.1
• 发表时间: 2007-10
• 期刊: Journal of the Atmospheric Sciences
• 影响因子: 3.1
• 作者: Gui‐Ying Yang;B. Hoskins;J. Slingo

Equatorial Waves in Opposite QBO Phases

QBO 相反相位的赤道波

• DOI: 10.1175/2010jas3514.1
• 发表时间: 2011
• 期刊: Journal of the Atmospheric Sciences
• 影响因子: 3.1
• 作者: Yang G

Convectively Coupled Equatorial Waves. Part III: Synthesis Structures and Their Forcing and Evolution

对流耦合赤道波。

• DOI: 10.1175/jas4019.1
• 发表时间: 2007
• 期刊: Journal of the Atmospheric Sciences
• 影响因子: 3.1
• 作者: Yang G