ATMOS Stratospheric Deuterated Water and Implications for Troposphere-Stratosphere Transport

The isotopic composition of stratospheric water vapor is used as a tracer for the convective history of air injected into the stratosphere. Stratospheric profiles of HDO, H2O,CH3D, and CH4 fro the ATMOS instrument, obtained over four missions from 1985-1994, are used to determine the initial deuterium-to-hydrogen ration of water vapor entering the stratosphere. We find that the initial DeltaD of stratospheric water is - 680 ± 80 (68 percent loss of deuterium), consistent with extrapolations from previous measurements at higher altitudes.