Sam: The problem with tgcmproc in the e5577 calculation was that O1 went negative in the model at high southern latitudes below about 100 km. I have put a fix in the processor that insures all densities are >= 1.e-20 before the solred calculation is done. So try it again -- although not necessary, you can limit the y-axis extent of vertical slices in log pressure to say -10 to +5 as follows: flon_zprange = -10.,5. ; 2 floats: zp range for y-axis flat_zprange = -10.,5. ; 2 floats: zp range for y-axis You can also limit the extent of the y-axis in height: flat_htscale = 100.,400.,5. ; 3 floats: ht range, delta for y-axis flon_htscale = 100.,400.,5. ; 3 floats: ht range, delta for y-axis --Ben