Understanding and Predicting the Impact of Outflow on Tropical Cyclone Intensification and Structure (Invited Presentation)

The purpose of this Office of Naval Research Departmental Research Initiative (DRI) is to enhance the understanding of dynamics of the upper-level outflow of tropical cyclones (TCs). Changes to TC outflow are increasingly believed to lead to profound changes in storm intensity and structure, but remain a largely unexplored aspect of TCs. Our goal is to improve the prediction of TC intensification and structure changes that occur in response to these influences, which may be due to environmental interactions and/or internal changes that are poorly represented in current models. The outflow characteristics, evolution, and dynamics will be investigated in a comprehensive manner using innovative new observing systems and satellite observations, as well as state-of-the-science models that will allow this upper-level region to be explored for the first time.

Investigations will focus on the understanding of the TC outflow region through theory, simulations, observations and model development. Research topics are envisioned to address the following overarching scientific issues related to the spatial and temporal evolution of TC outflow structure, dynamics, and processes: 1) the coupling of the TC outflow with the inner-core convection and the relationship of this coupling to intensity changes including rapid intensification, 2) the relationship between the upper-level outflow and the low-level wind field structure, 3) the interaction of tropical cyclone outflows with larger-scale features, and 4) the morphology and evolution of the outflow and its dependence on the environment.

This DRI is expected to run for five years, from FY14 to FY18. Collaboration is encouraged, and an observational component will be included in this DRI. For this purpose, ONR has established an initial collaboration with the NASA Hurricane and Severe Storms Sentinel (HS3) project taking place over the N. Atlantic from 2012-2014. We will also seek to collaborate with other agencies on a potential field program in the Western Pacific by leveraging one or more of the community research projects that are currently in the planning stages.