Coupling between gravity waves and tropical convection at mesoscales

Todd P. Lane, Fuqing Zhang

Research output: Contribution to journalArticle

42 Scopus citations

Abstract

An idealized cloud-system-resolving model simulation is used to examine the coupling between a tropical cloud population and the mesoscale gravity waves that it generates. Spectral analyses of the cloud and gravity wave fields identify a clear signal of coupling between the clouds and a deep tropospheric gravity wave mode with a vertical wavelength that matches the depth of the convection, which is about two-thirds of the tropospheric depth. This vertical wavelength and the period of the waves, defined by a characteristic convective time scale, means that the horizontal wavelength is constrained through the dispersion relation. Indeed, the wave- convection couplingmanifests at the appropriatewavelength, with the emergence of quasi-regular cloud-system spacing of order 100 km. It is shown that cloud systems at this spacing achieve a quasi-resonant state, at least for a few convective life cycles. Such regular spacing is a key component of cloud organization and is likely a contributor to the processes controlling the upscale growth of convective systems. Other gravity wave processes are also elucidated, including their apparent role in the maintenance of convective systems by providing a mechanism for renewed convective activity and system longevity.

Original languageEnglish (US)
Pages (from-to)2582-2598
Number of pages17
JournalJournal of the Atmospheric Sciences
Volume68
Issue number11
DOIs
StatePublished - Nov 1 2011

All Science Journal Classification (ASJC) codes

  • Atmospheric Science

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