1 Orography is a kind of local gazetteer, it has a long history.

2 The results show that the asymmetric distribution of orography and that of horizontal diffusion coefficients are likely to be the causes leading to the asymmetric motion.

3 A lee trough side is induced by the interaction of orography with the cold front.

4 Orography is properly introduced in the operational numerical model of Shanghai Institute of Typhoon and some real synoptic weather processes are used to test the dynamic effects of orography.

5 A two-level quasi-geostrophic low-order spectral model by both the orography and the periodic thermal forcings is used to study the changes of flow patterns.

6 The basic motion equations are simplified by perturbation method. The equations are computed by FFT numerical method with actual orography of Qinghai-Xizang Plateau and Rocky Mountains.

7 The clockwise circulation in the cold air can be obstructed wholly in the upward side by orography for the moving slowly steady cold front.

8 The results also show that both gravity wave drag and envelope orography have smaller influence on model results in the beginning of simulation, but greater in the later stage.

9 The inclination of SCF mainly depends on the geostrophic wind in the warm sector, frontal moving speed and the position of SCF relative to orography .