Premium
Small‐scale structure of O 2 + and proton hydrates in a noctilucent cloud and polar mesospheric summer echo of August 9/10 1991 above Kiruna
Author(s) -
Balsiger F.,
Kopp E.,
Friedrich M.,
Torkar K. M.,
Wälchli U.
Publication year - 1993
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/93gl02819
Subject(s) - mesosphere , ion , polar , water vapor , altitude (triangle) , proton , spectrometer , physics , range (aeronautics) , mass spectrometry , atmospheric sciences , atomic physics , materials science , meteorology , stratosphere , nuclear physics , astronomy , optics , geometry , mathematics , quantum mechanics , composite material
A novel mass spectrometer designed to measure simultaneously positive ion composition in the mesosphere, was successfully launched during the NLC‐91 project. Instruments supporting the mass spectrometer were a probe to measure both electrons and positive ions as well as a wave propagation experiment. The location of the Noctilucent Clouds (NLC) was determined by a particle impact sensor to detect secondary electrons and ions from the impact of NLC particle. The density of proton hydrates and of the related total ions is depleted in the NLC region at 83 km. An improved detection limit of 5 × 10 4 m −3 for positive ions and improved height resolution revealed for the first time large gradients in the O 2 + , H + (H 2 O) 2 and H + (H 2 O) 6 densities within a small height range of the order of 50 m. Such gradients at the altitude of NLC and Polar Mesospheric Summer Echoes (PMSE) are associated with strong variability of mesospheric water vapor, temperature and neutral air density.