Submesoscale Processes Triggered by Tropical Cyclones and Their Role in Temperature Recovery of Cold Wakes

Abstract

Submesoscale processes (submesoscales) play a crucial role in vertical tracer transport, which are typically stronger in winter than summer. However, recent studies revealed enhanced submesoscale activities following tropical cyclones (TCs) during summer months, though their characteristics, mechanisms, and dynamical impacts remain obscure. Through combining high-resolution satellite and simulation data, we demonstrate that energetic submesoscales are present within TC-induced cold wakes across the northwestern Pacific, which can produce strong upward vertical heat flux (VHF) in the upper ocean. Further analysis reveals that submesoscales are more active in stronger cold wakes induced by slower-moving and stronger TCs and they may be generated through a combination of baroclinic instability and strain-induced frontogenesis. Crucially, submesoscale VHF can accelerate the post-TC temperature recovery of cold wakes which may influence the sequential TC intensification. Our results improve the understanding of TC-ocean feedback and underscore the necessity of resolving or parameterizing submesoscales in TC prediction models.