Buoyancy of convective-scale updrafts in the outer cores of sheared tropical cyclones

ABSTRACT In this paper, the authors present the statistical characteristics of the buoyancy of outer-core convective-scale updrafts in numerically simulated sheared tropical cyclones (TCs). The total buoyancy is predominantly positive in weak-to-strong ambient vertical shears, whereas much of the total buoyancy under an extreme shear environment becomes negative. Thermal buoyancy positively contributes to the total buoyancy value. For weakly and moderately sheared TCs, the updraft buoyancy is statistically significantly stronger downshear but smaller upshear. Such a downshear preference of strong buoyancy becomes less evident as the shear magnitude increases. The total buoyancy of updrafts shows a decreasing tendency with radius. Both thermal and dynamic buoyancy do not significantly correlate with vertically averaged vertical mass fluxes. This also leads to no significant correlation between the total buoyancy and vertical mass fluxes of outer-core updrafts. Graphical Abstrac