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

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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.