Carbon Dioxide

The carbon dioxide has been increasing over the years.  This has a
direct affect on the radiation code.  The CO2 has an annual cycle
and is location dependent as more green means less CO2.

The CO2 files are monthly means on 15 degree resolution grid with no
vertical information.


Prior to 1950: use 1956 CO2 files
For 1956-2022: use observed CO2
2023: use projected CO2