Abstract
A grid-point global general circulation model (IAP GCM) suitable for medium and long-range developed and systematically weather predictions and climate simulations has been tested by a series of numerical simulations. The main characteristics of the model are as following:
(1) Introduction of departures of temperature T′, geopotential φ′ and surface pressure ps′ from their “standards” to cancel automatically the large trunctional errors in the mountain regions.
(2) Introduction of new coordinates and new variables. This leads the energy equation to a very compact form and the grid to a more flexible arrangement.
(3) The computational scheme exactly keeps the “available” energy conservation (if the dissipation is omitted), and is free from computational modes.
(4) The formulation and calculation of boundary terms or boundary conditions at the interfaces of atmosphere-ocean and atmosphere-land are physically consistent. Hence there is no false source.
The results of several basic numerical experiments show that the model has good computational stability and accuracy, and is able to simulate the most large-scale circulations and their variabilities. The simulated January and July climatic circulations and other elements are of reasonable accuracy. Furthermore, the model can successfully simulate the abrupt seasonal changes in the atmospheric general circulations over eastern Asia, the southern oscillation, the northern oscillation and the semi-annual oscillation. In addition, the simulated quasi-stationary oceanographic circulation driven by the simulated wind strees is also satisfactary.
