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The impact of the Moisture-Entrainment-Convection feedback on Spontaneous TC genesis

Presentation Date
Friday, December 11, 2020 at 4:00am



The processes responsible for the spontaneous tropical cyclone (TC) genesis in simulations of rotating radiative-convective equilibrium (RRCE) are not yet fully understood. Previous knowledge regarded radiative and surface-flux feedbacks as essential for spontaneous TC genesis. However, Ramírez-Reyes and Yang (2020, in revision) showed that spontaneous TC genesis can occur even in the absence of both feedbacks. Here, we use high-resolution simulations and mechanism-denial experiments to examine the role that the Moisture-Entrainment-Circulation (MEC) feedback plays in spontaneous TC genesis. In the MEC feedback, moisture is detrained from convecting regions, which moistens the atmosphere making it more favorable for new convective events. This feedback has been proposed to be important in helping the organization of convection in non-rotating simulations. In this work, we weaken the MEC feedback by relaxing the clear-sky water vapor mixing ratio to its horizontal mean at different timescales. We find that TCs can still self-emerge in the absence of radiative and surface-flux feedbacks. However, the intensity of the TCs changes systematically with the nudging timescale.



Ramírez-Reyes, A., & Yang, D. (2020, April 18). Spontaneous Cyclogenesis without Radiative and Surface-Flux Feedbacks. EarthArXiv

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