AbstractThe nature, abudance, and variability of positive and negative ions in the middle atmosphere have been investigated in the past two decades with in-situ measurements of cryogenically pumped mass spectrometers. Mainly quadrupole mass filters and magnetic/single-focussing instruments were used on sounding rocket and ballon payloads. The essential discovery of the first positive ion measurements was the appearence of water cluster ions H+(H2O)n' commonly referred as proton hydrates. In the stratosphere also other more complex cluster ions, such as H+ (CH3CN)n(H2O)m, have been identified. The most recent chemical models, which are based on reaction constants measured in the laboratory, can reasonably well explain the transition from the primary ion NO+ and/or O2+ into proton hydrates below about 85 km altitude. This transition height and the abundance of different proton hydrates are sensitive to temperature variations, to the nature and strength of ionization sources, and to the concentrations of atomic oxygen, nitric oxide, and water vapor.Knowledge of the production and loss of negative ion species is still very limited. The reason is, on one side, the large number of negative ion species present in the middle atmosphere and, on the other side, the insufficient coverage of reactions studied in the laboratory.Two important negative ion classes, namely NO3−(HNO3)n and HSO4−(H2SO4)q(HNO3)p, were - despite these problems - identified in the stratosphere. From these ions the determination of neutral HNO3 and H2SO4 in the gas phase became possible.
Positive and negative ions of the middle atmosphere
Advances in Space Research ; 12 , 10 ; 325-333
1992-01-01
9 pages
Article (Journal)
Electronic Resource
English
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