Variability and Predictability of African Easterly Waves

该项目将增进我们对非洲东风波特征的性质和可变性的认识和理解，以及决定非洲东风波在每日和季节内时间尺度上的可预测性的过程。这项工作计划围绕两个相辅相成的主题：(一)预警工作的可变性和(二)预警工作的可预测性。变异性工作将结合观测值的统计分析和在理想化建模和个案研究方法支持下的数值预报分析，以确定日间季节内时间尺度上气旋预报特征变化的程度和原因。预报敏感度分析将探索可预报性工作，并将与可变性工作密切互动并从中受益。与主要与干动力有关的中纬度系统不同，AEW为了解干湿动力同等重要的一类现象的大气可预报性提供了机会。对关注西非地区的天气预报员以及对下游热带气旋发生的可能性感兴趣的天气预报员来说，增进对AEW的可变性和可预报性的认识和了解是重要的。在这个项目中获得的知识将被用来更新我们网页上的诊断信息，用于对AEW和AEW活动的常规监测，这些预报员使用这些活动。虽然AEWS对北方夏季的大量降雨负有责任，但这项工作也适用于对社会很重要的一系列应用，包括水文学(和洪水预报)、农业(和作物预报)和健康(包括疟疾风险评估)。虽然这类申请不会在本项目中处理，但将努力将这项研究的结果传达给相关社区。要做到这一点，一种方法是通过与非洲季风多学科分析(AMMA)项目中从事这些领域工作的科学家进行沟通。

This project will improve our knowledge and understanding of the nature and variability of African easterly wave characteristics and the processes that determine the predictability of African easterly waves at daily-to-intraseasonal timescales. The work is planned around two complementary themes: (i) variability of AEWs and (ii) predictability of AEWs. The variability-work will combine statistical analysis of observations and NWP analyses supported by idealized modeling and a case-study approach to determine the extent to which AEW characteristics vary at daily-to-intraseasonal timescales and why. The predictability work will be explored using forecast sensitivity analyses and will interact strongly with and benefit from the variability work.AEWs provide an opportunity to understand atmospheric predictability for a class of phenomenon where dry and moist dynamics are of equal importance, unlike midlatitude systems that are primarily associated with dry dynamics. Increased knowledge and understanding of the variability and predictability of AEWs is important for weather forecasters concerned with the West African region as well as those interested in the potential for tropical cyclogenesis downstream. The knowledge gained in this project will be used to update the diagnostics on our webpages used for routine monitoring of AEWs and AEW-activity that are used by such forecasters. AEWs are responsible for a significant amount of rainfall during the boreal summer, this work is also applicable to a range of applications important for society including hydrology (and flood prediction), agriculture (and crop prediction) and health (including malaria risk assessments). While such applications will not be dealt with in this project, efforts will be made to communicate the results of this research to the relevant communities. One way to do this will be through communication with scientists working in these areas within the African Monsoon Multidisciplinary Analysis (AMMA) project.