The First Satellite Measurements of HFC-125 by the ACE-FTS: Long-term Trends and Distribution in the Earth’s Upper Troposphere and Lower Stratosphere

HFC-125 (CF3CHF2, pentafluoroethane) volume mixing ratios (VMRs) have been determined for the first time using infrared absorption spectra from the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) from 2004 to 2024. These VMRs provide global altitude-latitude VMR distributions. A VMR time series for HFC-125 has also been calculated and compared to values from in situ discrete flask measurements conducted by the National Oceanic and Atmospheric Administration Earth System Research Laboratory. The abundance of HFC-125 is currently experiencing exponential growth. ACE data shows a growth rate of 3.47 +/- 0.05 ppt/year in the past six years.