This paper presents the first global data set of atmospheric concentrations of the isotopologues of methane as measured by ACE-FTS. Both CH3
D and 13
show enrichment at higher altitudes and some seasonal variation at the poles. After applying a constant correction factor to the CH3
D data set, good agreement with existing balloon measurements is achieved. However, 13
still shows a large amount of error. Improved lab measurements of CH4
would help reduce errors in the ACE-FTS data.