Spontaneous Tropical Cyclogenesis without Radiative and Surface-Flux Feedbacks.

Monday, December 9, 2019 - 11:20
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We study spontaneous tropical cyclone (TC) genesis using a cloud-resolving model (CRM) over an f-plane with constant sea-surface temperature. Previous studies propose that spontaneous TC genesis requires at least a surface-flux feedback or a radiative feedback (Wing et al. 2016, Muller and Romps 2018). Here we test this hypothesis by performing mechanism-denial CRM experiments, in which we switch off both feedback processes. We find that TCs can still self-emerge even without radiative and surface-flux feedbacks, although these feedbacks accelerate the genesis and impact the intensity and scale of TCs at equilibrium. We then analyze the available potential energy (APE) budget of TCs. We show that TC genesis is associated with abrupt increase in APE and that convective heating dominates the APE production. Our result suggests that spontaneous TC genesis may result from a cooperative interaction between convection and circulation.

Wing, Allison A., Suzana J. Camargo, and Adam H. Sobel. “Role of Radiative–Convective Feedbacks in Spontaneous Tropical Cyclogenesis in Idealized Numerical Simulations.” Journal of the Atmospheric Sciences 73, no. 7 (July 2016): 2633–42. https://doi.org/10.1175/JAS-D-15-0380.1.

Muller, Caroline J., and David M. Romps. “Acceleration of Tropical Cyclogenesis by Self-Aggregation Feedbacks.” Proceedings of the National Academy of Sciences 115, no. 12 (March 20, 2018): 2930–35. https://doi.org/10.1073/pnas.1719967115.

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