In this mode, four very similar variables are output: TW1_URB4D, TW2_URB4D, TW1LEV_URB3D, and TW2LEV_URB3D. What do these four variables respectively represent? Are they wall/surface temperatures? If so, which one is more exterior and which is more interior? One of the dimensions is related to direction, with ndm=2 - what specifically does this direction represent (east-west or north-south)?