With this option the vertical resolution of the atmosphere_file data is changed to the levels (in km above sea surface) given as argument. This might be useful in oder to reduce the number of levels (save computational time) or in order to easily adjust the atmosphere profile to the resolution of a Monte Carlo cloud file wc_file 3D or ic_file 3D.  

atm_z_grid 0 2 4 6 8 10 20 30 ...