抄録
The atmospheric dynamic equations have been transformed from the 2-coordinate system into a generalized vertical coordinate system by using a so-called DDD (difference differential-difference) transformation method. Then the generalized system is assumed being pressure, sigma or combined pressure-sigma coordinate system and corresponding equations are obtained with the second-order accuracy. It is pointed out that the usual equations are only of the first-order accuracy when their space-differential terms are simply approximated by central finite differences. Therefore the usual forms of the equations may result in quite large errors on steep slopes of mountains included in a model.
