Climate Influences Affecting Atlantic Tropical Cyclones Variability and ENSO-QBO Relationships

该项目包括两个研究项目，一个是关注与西非降雨相关的大西洋地区强热带气旋的年际和长期变化，另一个是研究平流层QBO如何调节强烈的赤道对流，从而影响ENSO的长期变化。该指数表明，大西洋强烈飓风活动的周期性变化与西非萨赫勒地区降雨的同步变化密切相关。正在进行的研究试图建立一个将飓风变率和萨赫勒干旱与观测到的全球尺度气候变化联系起来的物理过程的概念模型。该项目计划审查西非当地和区域反馈过程的影响，以及影响热带大西洋和更偏远地区条件的更大规模因素。该项目的这一部分将有助于我们了解控制大西洋热带气旋的发生、增强、运动和寿命的过程的气候变率，同时也为大西洋飓风活动的季节性预报提供改进。第二项次要的（约占总努力的35-40%）研究计划旨在了解平流层QBO变化、诱导风切变和平流层低层温度异常之间的明显联系，这与赤道西太平洋上空集中的深层对流有关。QBO诱导的对流振荡似乎与ENSO周期变化有很强的物理联系。这项研究很重要，因为它试图增加对气候年际变化的理解。

This program consists of two research initiatives, one that focuses on interannual and longer term variability of intense tropical cyclone in the Atlantic region as related to West African rainfall and the other which examines how the stratospheric QBO modulates intense equatorial convection and, thereby, affects the longer term variability of the ENSO. The PI has shown that recurrent variations of intense Atlantic hurricane activity are closely correlated with concurrent variations of rainfall in the West Africa Sahel region. Ongoing studies seek to develop a conceptual model of the physical processes linking both hurricane variability and Sahel drought with observed global-scale climate variations. The PI plans to examine the effects of local and regional feedback processes in West Africa as well as larger scale factors affecting conditions in the tropical Atlantic and in more remote areas. This portion of the program will contribute to our understanding of the climatological variability of processes governing the genesis,intensification, movement an longevity of Atlantic tropical cyclones while also providing improvements to seasonal forecasts of Atlantic hurricane activity. The second, but subordinant (about 35-40% of the total effort) research initiative is directed to understanding an apparent association between variable stratospheric QBO, induced wind shear and temperature anomalies in the lower stratosphere in relation to concentrated deep convection over the equatorial West Pacific. QBO induced convective oscillations appears to have a strong physical link with ENSO cycle variations. This research is important because it seeks to increase understanding of the interannual variability of climate.