The variation of the spectral structure of the internal inertio-gravity waves (ⅡGWs) propagating in the atmospheric wind shear environments is discussed in this paper. From the hydrodynamic equation set in Boussinesq...The variation of the spectral structure of the internal inertio-gravity waves (ⅡGWs) propagating in the atmospheric wind shear environments is discussed in this paper. From the hydrodynamic equation set in Boussinesq approximation, a spectral propagation equation ⅡGWs satisfy is derived, then the spectral correspondence in the upper atmosphere is numerically calculated, after a forced spectrum is given as a Van- Zandt one at the lower boundary. The results show that if ⅡGWs do not encounter the critical-layer absorp- tion, then their spectral structure may be not changed significantly; otherwise it may be changed greatly, and a few of spectral components are filtered. Also the isotropy of the assumed VanZandt spectrum is distorted in upward-propagating process. That is the directional filtering effect of the atmospheric wind on the gravity wave spectrum.展开更多
Geostrophic adjustment and frontogenesis are examined by means of the 2-D ARPS model. The simulation shows that.without the large-scale forcing,both the frontogenesis and frontolysis are observed during the geostrophi...Geostrophic adjustment and frontogenesis are examined by means of the 2-D ARPS model. The simulation shows that.without the large-scale forcing,both the frontogenesis and frontolysis are observed during the geostrophic adjustment process and the intensity of the front oscillates in the case of no discontinuity.The convergence (divergence) induced by the secondary circulation is the most important factor for frontogenesis (frontolysis) at the top and bottom boundaries.The amplitude and period of oscillation are dependent on the initial atmospheric stratification and the Coriolis frequency,and they are related to the inertio-gravity wave.展开更多
文摘The variation of the spectral structure of the internal inertio-gravity waves (ⅡGWs) propagating in the atmospheric wind shear environments is discussed in this paper. From the hydrodynamic equation set in Boussinesq approximation, a spectral propagation equation ⅡGWs satisfy is derived, then the spectral correspondence in the upper atmosphere is numerically calculated, after a forced spectrum is given as a Van- Zandt one at the lower boundary. The results show that if ⅡGWs do not encounter the critical-layer absorp- tion, then their spectral structure may be not changed significantly; otherwise it may be changed greatly, and a few of spectral components are filtered. Also the isotropy of the assumed VanZandt spectrum is distorted in upward-propagating process. That is the directional filtering effect of the atmospheric wind on the gravity wave spectrum.
基金This research was supported by the National Natural Science Foundation of China under Grants:49675259 and 49735180The National Key Basic Research Development Program:CHERES
文摘Geostrophic adjustment and frontogenesis are examined by means of the 2-D ARPS model. The simulation shows that.without the large-scale forcing,both the frontogenesis and frontolysis are observed during the geostrophic adjustment process and the intensity of the front oscillates in the case of no discontinuity.The convergence (divergence) induced by the secondary circulation is the most important factor for frontogenesis (frontolysis) at the top and bottom boundaries.The amplitude and period of oscillation are dependent on the initial atmospheric stratification and the Coriolis frequency,and they are related to the inertio-gravity wave.
