Intraseasonal Variability of the West African Monsoon

将使用多年数据记录在北方夏季期间检查西非季风系统的季节内变化。 研究计划如下：-表征和理解在季节内时间尺度上观察到的撒哈拉以南西非北部夏季变化。确定这种季节内变化是否以及如何与全球变化模式相联系，例如对流耦合赤道波和Madden-Julian振荡。确定季节内气流变化是否与非洲东风波活动的调制有关，如以前的研究所建议的那样。 最重要的是，检查天气波能量收支的季节内变化以及大尺度位涡梯度，以确定为什么会发生这种季节内调制。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生成的调制有关。 还确定非洲西部的大西洋热带辐合带（ITCZ）受到影响的程度。确定撒哈拉以南非洲地区夏季季节内变化是否是可预测的。这项工作补充了非洲季风多学科分析项目正在进行的工作。 与AMMA更密集的空间和时间采样，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Paula白色在俄勒冈州州立大学（OSU）的研究生学习。 白色女士自2005年冬季以来一直是俄勒冈州立大学的研究生。 她是一个自我激励和勤奋的学生，这个项目的许多（如果不是大部分）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。 这项研究可能产生的信息将改善西非-东部热带大西洋地区的天气和气旋预测。

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.