Intraseasonal Variability of the West African Monsoon

西非季风的季节内变化

• 批准号: 0946911
• 负责人: Eric Maloney
• 金额: $ 21.42万
• 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: 2010
• 资助国家: 美国
• 起止时间: 2010-03-01 至 2014-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0946911&HistoricalAwards=false
• 关键词: Intraseasonal; Variability; West; African; Monsoon

The Madden-Julian Oscillation (MJO) modulates tropical cyclones and easterly waves in the Atlantic, providing the potential for prediction of enhanced Atlantic hurricane activity a couple of weeks in advance. This project will address several major outstanding questions: (i) the teleconnection pathway by which the MJO affects the Atlantic during boreal summer, (ii) how west African and Atlantic precipitation is actually initiated by the MJO once the teleconnection is established, (iii) the mechanism by which the MJO modulates African easterly waves, and (iv) how these easterly waves feed back to influence the MJO.A hierarchy of models will be used to understand the teleconnection pathways by which the MJO affects the Atlantic and west Africa, including the non-divergent barotropic vorticity equation, a filtered shallow water model on a sphere, and an atmospheric general circulation model. Because it is hypothesized that the MJO first initiates convection anomalies over the Darfur region of the Sudan, several observational products (e.g. Cloud Archive User Service (CLAUS) brightness temperature, Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation Climatology Project (GPCP) precipitation) will be used to document the time evolution of precipitation in west Africa as a function of MJO phase. A primitive equation model will be used to test the hypothesis that strong heating variations over the Darfur region forced by the MJO modulate the amplitude of easterly wave activity in west Africa and the Atlantic, and test the hypothesis that MJO-related structural changes in the African easterly jet significantly affect easterly wave growth. Further, the impact of MJO-related easterly wave variability on the column-integrated intraseasonal moisture budget in west Africa and the Atlantic will be examined in satellite and reanalysis datasets. The broader impacts of this work are educational and in the potential to improve our prospects for medium range prediction of periods of enhanced Atlantic tropical cyclone activity.

Madden-Julian振荡（MJO）调节了大西洋的热带气旋和东风波，为预测增强的大西洋飓风活动的潜力提前了几周。该项目将解决几个主要问题：（i）MJO在北方夏季影响大西洋的链连接途径，（ii）（ii）建立远程连接的MJO实际上是如何启动的，一旦建立了远程连接，（iii）MJO对非洲的机制进行了调节，以及这些机构对这些狂潮的影响（iv），以及伊斯特式（IV）的往福将供应到伊斯特（IV）。模型将用于理解MJO影响大西洋和西非的链连接途径，包括非散发性的正压涡度方程，球体上过滤后的浅水模型以及大气的一般循环模型。因为假设MJO首先启动了苏丹达尔富尔地区的对流异常，所以将使用几种观察产品（例如云存档用户服务（CLAUS）亮度温度，热带降雨测量任务（TRMM）和全球降水学项目（GPCP）降水量将用于使用West Antive As nifica As Fiqual Asification in Africa As narkoa As narkoa As nifica a in Function Morjo As a nifica a in Function a in Niffication a in Function Morjo As a in Function a in Function Morjo As a in Function a in Africa As a in Afripa a in niffication。原始方程模型将用于检验以下假设：MJO强迫的Darfur区域的强加热变化调节了西非和大西洋的东部波浪活动的幅度，并检验了MJO与非洲东部射流中与MJO相关的结构变化的假设，会显着影响东部波浪的生长。此外，将在卫星和重新分析数据集中检查与MJO相关的东部波动变异对西非和大西洋季节内的水分预算的影响。这项工作的更广泛影响是教育性的，有可能改善我们对增强大西洋热带气旋活性时期中等范围预测的前景。