double t_strato = ISA_def[1].temp - atmodel::freezing;
if (temperature_degc < t_strato) temperature_sea_level_degc = t_strato;
else temperature_sea_level_degc =
double t_strato = ISA_def[1].temp - atmodel::freezing;
if (temperature_degc < t_strato) temperature_sea_level_degc = t_strato;
else temperature_sea_level_degc =