Atmospheric model NRLMSISE-00: problem at 35 km
if (alt < ZN3) should be changed to
if (alt <= ZN3)
TBN: the ftp site (for the Fortran version) is no longer available. As seen in NRLMSISE-00 - Dr. Dominik Brodowski page, the Fortran page should be http://uap-www.nrl.navy.mil/models_web/msis/msis_home.htm but is not available either ...