Momentum Flux Spectrum of Convective Gravity Waves. Part I: An Update of a Parameterization Using Mesoscale Simulations

• DOI: 10.1175/2010jas3552.1
• Publication Date: 2010-12-27T22:18:48Z
• Authors: Hyun-Joo Choi; Hye-Yeong Chun
• Keywords: Momentum (technical analysis); Mass flux; Convective storm detection

Abstract The convective source and momentum flux spectra of a parameterization gravity wave drag (GWDC) are validated in three-dimensional spectral space using mesoscale numerical simulations for various ideal real storms. From this, two important free parameters included the GWDC parameterization—the moving speed propagation direction—are determined. In simulations, spectrum shows nearly isotropic features terms magnitude, its primary peak any azimuthal direction occurs at phase that equals same direction. It is found closely correlated with basic-state wind averaged below 700 hPa (u700 υ700). When analytic calculated as determined by u700 υ700, shape all storm cases agrees from simulation. launch level (cloud top) also conditions υ700. A comparison between simulation results reproduces reasonably well. parameterization, directions 45° (northeast southwest) 135° (northwest southeast) best represent integrated over when minimum number required computational efficiency.