Mass spectrometric measurements of fractional ion abundances in the stratosphere—Positive ions

Measured fractional abundances for stratospheric positive ions are reported for the first time. The measurements which were obtained from balloon-borne ion mass spectrometer experiments relied on recent simulation studies of electric field induced cluster ion dissociation conducted at our laboratory.The ion abundance data provide strong support for identifications of the observed ions as H⁺(H₂O)_n and Hx⁺x_L(H₂O)_m proposed previously. Moreover, it is found that x most likely cannot be identified as NaOH or MgOH which implies that gaseous metal compounds do not exist in the middle stratosphere in significant abundances.Implications of the present findings for the composition and chemistry of stratospheric ions as well as for stratospheric aerosols are discussed.