HR: 11:40h
AN: A32A-08    [Abstracts]
TI: Using Cloud-resolving Regional Model to Study Gravity Wave Generation by Hector Convection and Their Effect on Large-scale Circulation
AU: * Stenchikov, G
EM: gera@envsci.rutgers.edu
AF: Department of Environmental Sciences, Rutgers University, 14 College Farm Road, New Brunswick, NJ 08904 United States
AU: Hamilton, K
EM: kph@hawaii.edu
AF: International Pacific Research Center, University of Hawaii, 1680 East-West Road, Honolulu, HI 96822 United States
AB: Gravity waves generated by strong convection transport momentum and energy from troposphere into the middle atmosphere. This mechanism plays an important role in the dynamics of the middle atmosphere. However the related processes are yet not well quantified. The Darwin Area Wave Experiment (DAWEX) focused on observation of gravity wave propagation from the Hector convection at Tiwi Islands during October-December, 2001 using various instrumentation including 5 airglow images, radars, and boundary layer wind profiler. Here we present the results of a numerical case-study of Hector event observed on November 16, 2001 during DAWEX IOP2 aiming to better understand and quantify the convective generation of gravity waves, there further propagation in the middle atmosphere, interaction with the mean flow, and breaking above 100 km at the mesopause region. We employed a regional atmospheric modeling system (RAMS). RAMS is a comprehensive non-hydrostatic model with developed cloud microphysical parameterization and interactive (with cloud microphysics) radiative transport. The calculations were conducted in the horizontal domain of 400km x 500 km, that was extended vertically up to 130 km. Horizontal and vertical grid spacing were respectively 2km x 2km and from 30 to 1000m. The model was initialized from balloon soundings combined with the UKMO and URAP analysis profiles. The simulated storm has good timing and location. The intensity of the storm is in a good agreement with the observations by Australian Bureau of Meteorology Research Center C-band polarized radar. The latent heat release during the convection reached 4000 K/day. The vertical velocity perturbations caused by gravity waves propagated into the mesosphere reached 1 m/s at the altitude of 100 km. The wave phase speed and wave perturbations are compared with the airglow imager observations at Katherine and Wyndham sites that were located respectively about 350 and 450 km south of Tiwi Islans.
DE: 3334 Middle atmosphere dynamics (0341, 0342)
DE: 3337 Numerical modeling and data assimilation
DE: 3384 Waves and tides
DE: 0320 Cloud physics and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting