Whole-Atmospheric Version 1.0 of GAMIL (W-GAMIL1.0): Description and Evaluation

Based on the Grid-point Atmospheric Model of the Institute of Atmospheric Physics LASG version 3 (GAMIL3) with 2° horizontal resolution, the whole-atmospheric model named W-GAMIL1.0, with a high top (approximately 0.01 hPa) and 137 vertical levels, was developed through modifying the standard stratification profile and interpolation method, incorporating non-orographic gravity wave (NGW) parameterization schemes, and adjusting the convective processes for strong variability. Twenty-six-year Atmospheric Model Intercomparison Project integrations indicated that W-GAMIL1.0 markedly improves the stratospheric dynamical variables owing to its high model lid and increased vertical resolution, including reductions in cold biases and dry biases in the tropic. When the frequency and accumulation of convective precipitation are increased through changing the convection scheme, the Madden–Julian Oscillation (MJO) convection, Quasi-Biennial Oscillation (QBO) westerlies and downward propagation are strengthened substantially. The mean period, height of maximum amplitude, and lowest level of the QBO are also well reproduced. Under the background of strong QBO westerlies, the Semi-Annual Oscillation (SAO) westerly and the frequency of sudden stratospheric warming events are obviously overestimated in W-GAMIL1.0, mainly because of (convective) gravity wave forcing. However, the eastward propagation of MJO convection, the vertical and latitudinal extents as well as the amplitude and descent rate of the QBO, and the SAO easterly are all underestimated, indicating the importance of compatibility between the vertical and horizontal resolutions, and between the convective process and convective NGW process in the development of a whole-atmospheric model.