A Modeling Study of Tropical Intraseasonal and Synoptic Variability in West Africa and the Americas

西非和美洲热带季节内和天气变化的模拟研究

• 批准号: 1347738
• 负责人: Eric Maloney
• 金额: $ 28.82万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1347738&HistoricalAwards=false
• 关键词: Modeling; Study; Tropical; Intraseasonal; Synoptic

This project is a study of tropical easterly waves with two distinct components. The first component is an examination of the influence of the Madden-Julian Oscillation (MJO) on African Easterly Waves (AEWs). The research would focus on the hypothesis, motivated by the PI's prior research, that the MJO affects the "triggering" of AEWs in the region of the Darfur highlands at the entrance to the African Easterly Jet (AEJ). The proposed mechanism for this influence is the westward propagation of MJO-induced Rossby waves from the Indian Ocean, which modulate the meridional transport of moisture in the AEJ entrance region. The second component addresses the origins of easterly wave activity in the Caribbean Sea and the Eastern Pacific (EP). Previous studies have argued that easterly waves in this region are actually AEWs which become re-invigorated after crossing the Atlantic. Work performed here will test the alternate hypothesis that the conducive basic state and multiple vorticity sources in the region should suffice to generate easterly waves in the absence of any "seeding" from trans-Atlantic AEWs. The work performed in both components consists of numerical experiments with the Weather Research and Forecasting (WRF) model, a regional model in which the boundary conditions can be filtered to allow or exclude the influence of Rossby waves and AEWs propagating into the model domain.Tropical easterly waves are the precursors of tropical cyclones (including landfalling hurricanes), and thus are important for the prediction of significant weather hazards. Thus, the work has societal broader impacts through its relevance for practical weather prediction. In addition, the work will support and train two graduate students, thereby providing for the development of the future workforce in this research area.

该项目是对具有两个不同组成部分的热带东方波浪的研究。 第一个组成部分是对Madden-Julian振荡（MJO）对非洲东部波浪（AEWS）的影响的检查。这项研究将重点放在PI先前研究的推动下的假设上，即MJO会影响非洲东部喷气式飞机（AEJ）入口处达尔富尔高地地区AEWS的“触发”。提出的这种影响的机制是从印度洋引起的MJO诱导的Rossby波的向西传播，这调节了AEJ入口区域中水分的子午运输。第二部分介绍了加勒比海和东太平洋（EP）中东方波动活动的起源。先前的研究表明，该地区的东方波浪实际上是越过大西洋后重新染色的。这里进行的工作将检验替代假设，即该地区的有利基本状态和多个涡度来源应足以在没有跨大西洋AEWS的任何“播种”的情况下产生东风波。 在两个组件中进行的工作都由天气研究和预测（WRF）模型进行的数值实验，该模型可以过滤边界条件以允许或排除Rossby Waves的影响或AEWS的影响，并将其传播到模型领域中。热带东方的浪潮是热带范围的范围的重要范围（包括陆地上的重要天气），以及陆地上的范围，以及降落的危险范围。因此，这项工作通过其与实际天气预测的相关性产生了更广泛的影响。此外，这项工作将支持和培训两名研究生，从而为该研究领域的未来劳动力提供发展。