137 Deep Convection and the Initial Vertical Alignment of Tropical Vortices

Tuesday, 17 April 2018
Champions DEFGH (Sawgrass Marriott)
Charles N Helms, NASA/GSFC, Greenbelt, MD

As a mature hurricane typically has a vertically-aligned vortex, the vertical alignment process represents an important step in hurricane formation. Much of the research on the vertical alignment process focuses on how an initially-upright vortex recovers from being tilted by vertical wind shear. In these studies, the low- and midlevel vortices are often separated by less than 100 km. The present study aims to examine the vertical alignment processes for low- and midlevel vortices that are initially separated by more than 100 km, as is often the case in weak tropical disturbances; the midlevel vortex in a weak tropical disturbance is often a distinct entity from the low-level vortex rather than an upward extension of the low-level vortex. We hypothesize that the low- and midlevel vortices of a tropical disturbance come into vertical alignment primarily via the generation of a low-level vortex in close proximity to the midlevel vortex due to the action of deep convection. This presentation will examine the various theories for vertical alignment of both tilted vortices and initially-separated vortices. Additionally, the presentation will discuss the methods by which a combination of observations and numerical simulations will be used to test our hypothesis.
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