Mesoscale Gravity Waves in Moist Baroclinic Jet-Front Systems

Junhong Wei*(1) and Fuqing Zhang(1), Jadwiga H. Richter(2)
(1)Department of Meteorology, the Pennsylvania State University; (2)National Center for Atmospheric Research

This presentation introduces the propagating characteristics, sources, dynamics and impacts of the gravity waves generated in the moist baroclinic jet-front systems. Firstly, a series of high-resolution cloud-permitting simulations of idealized moist baroclinic waves are performed to study gravity waves among moist baroclinic jet-front systems with varying degree of convective instability, to examine the similarities and differences of wave characteristics, initiations and propagations among different simulations, and to understand the coupling and interactions of gravity waves with small-scale moist convection and large-scale background baroclinic waves. Secondly, four-dimensional linear ray-tracing experiments are employed to investigate the source mechanisms, propagating characteristics, life cycles, and wavenumber vector refraction budget analysis of the identified lower-stratospheric gravity waves. Finally, this study also utilizes the discrete Fourier transform to compare the gravity wave spectral characteristics among different high-resolution idealized moist experiments, with the intent of improving nonorgraphic gravity wave parameterizations. It is hypothesized from the analysis that the dry gravity wave source generates a relatively narrow and less symmetrical power spectrum centered around lower phase speeds and horizontal wavenumbers, whereas the moist gravity wave source generates a broader and more symmetrical power spectrum, with a broader range of phase speeds and horizontal wavenumbers.



*email: jwei@psu.edu
*Preference: Invited