Intraseasonal Variability of the West African Monsoon

将利用数十年的数据记录，在北部夏季研究西非季风系统的季节内变化。研究计划如下：-在季节内时间尺度上描述和理解观察到的撒哈拉以南西非北部夏季变率。-确定这种季节内变率是否以及如何与全球变率模式有关，如对流耦合赤道波和马登-朱利安振荡。-确定季节内气流变化是否如先前研究所建议的那样与非洲东风波活动的调制有关。最重要的是，研究天气波能量收支的季节内变化以及大尺度位涡梯度，以确定这种季节内调制可能发生的原因。-确定撒哈拉以南非洲地区风和降水的季节内变化是否与大西洋热带气旋发生的调制有关。还要确定非洲西部的大西洋热带间辐合带(ITCZ)受到影响的程度。-确定撒哈拉以南非洲的夏季季节内变化是否可预测。这项工作是对非洲季风多学科分析(AMMA)项目正在进行的工作的补充。与AMMA更密集的时空采样，但记录长度更短的结果进行比较，将被证明是特别有用的。更广泛的影响：该项目将资助俄勒冈州立大学(OSU)保拉·怀特的研究生学习。怀特女士自2005年冬季季度以来一直是俄亥俄州立大学的研究生。她是一个自我激励和勤奋的学生，这个项目的许多(如果不是大多数)想法都是她自己的。她将在科学会议和出版物上展示她的研究成果。这项研究可能会产生改善西非-东部热带大西洋地区天气和气旋预报的信息。

The intraseasonal variability of the West African monsoon system will be examined during boreal summer using a multidecadal data record. The research plan is as follows:- Characterize and understand observed boreal summer variability over sub-Saharan West Africa on intraseasonal timescales.- Determine if and how such intraseasonal variability is connected to global modes of variability such as convectively coupled equatorial waves and the Madden-Julian oscillation.- Determine if intraseasonal flow variations are associated with modulation of African easterly wave activity, as suggested by previous studies. Most importantly, examine intraseasonal variations in the energy budget of synoptic waves and also the large-scale potential vorticity gradient to determine why such intraseasonal modulation may occur.- Determine if intraseasonal variability in winds and precipitation over sub-Saharan Africa is connected to a modulation of Atlantic tropical cyclogenesis. Also determine the extent to which the Atlantic Inter-Tropical Convergence Zone (ITCZ) to the west of Africa is affected.- Determine if summertime intraseasonal variability over sub-Saharan Africa is predictable.The work complements ongoing work in the African Monsoon Multidisciplinary Analysis (AMMA) project. A comparison to results derived from the denser spatial and temporal sampling, but shorter record length, of AMMA will prove particularly useful.Broader impacts: This project will fund the graduate studies of Paula White at Oregon State University (OSU). Ms. White has been a graduate student at OSU since Winter Quarter of 2005. She is a self - motivated and hardworking student, and many (if not most) of the ideas for this project are her own. She will present her research results at scientific meetings and through publications. The research may produce information that will improve weather and cyclone prediction in the West African- eastern tropical Atlantic region.