Dynamical framework with blocking topography coordinates for atmospheric GCM and its validation
LIN Zhaohui~1, ZHANG Ming~(1,2), LIANG Danqing~(1,2) WANG Aihui~1, ZHANG Dongling~1 & ZENG Qingcun~1 1. ICCES, Institute of Atmospheric Physics, Chinese Academy of Sciences. Beijing 100029. China; 2. College of Meteorology. PLA University of Science and Technology, Nanjing 211101. China
The dynamical framework with Blocking To- pography Coordinates (hereafter, BTC), which is suited to handle the steep topography for the atmospheric general circulation models, is presented in this paper, together with its validation results. The integral properties of both the dif- ferential and finite-difference equations for the BTC dy- namical core are: gross mass conservation, quadratic con- servation for advection terms, Coriolis force does not change the kinetic energy, conservation of total available energy. The improved nonlinear iteration scheme is utilized for the time-integration. The energy conservation for BTC dynami- cal core is validated by using the integration results from 9-layer and 21-layer version respectively. Comparison results show that, the changes of the kinetic energy and total avail- able potential energy during the integration are quite close for both the BTC dynamical framework and the dynamical framework of IAP 9-level and IAP 21-level AGCM, and this may suggest that the BTC dynamical core can be used for long-term integration with good computational stability. Furthermore, the BTC dynamical core has the advantage over the terrain following (sigma) coordinates in its better representation of the influence of the large-scale topography on the atmospheric general circulation. Finally, the correct- ness and reasonableness of the BTC dynamical core has been further proved by the numerical simulation of the topogra- phy influence on the quasi-stationary planetary wave with 21-layer version of BTC dynamical framework.