" \"tendency_of_X\" means derivative of X with respect to time. The construction \"atmosphere_moles_of_X\" means the total number of moles of X in the entire atmosphere, i.e. summed over the atmospheric column and over the entire globe. The chemical formula for propane is C3H8. Propane is a member of the group of hydrocarbons known as alkanes. There are standard names for the alkane group as well as for some of the individual species." . "Climate and Forecast (CF)" . . . "tendency of atmosphere moles of propane" . .