A New Method to Measure Water Vapor Content of the Polar Middle Atmosphere Using Potochemical Reaction "H2O + hν(121.6nm) → OH*+H"

A method of water vapor measurement in the upper troposphere and the stratosphere of the polar region is described. This technique is due to the photochemical reactions, H_2O+hν (Lyman-alpha line) ⟶OH (A^2Σ^+)+H, OH (A^2Σ^+)⟶OH (X^2II)+hν (309nm), and has several advantages such as fast response and high sensitivity, besides being relatively free from contamination. Results of laboratory experiments suggest that this method is possibly very useful for monitoring the content of water vapor under a very dry atmospheric condition like the polar middle atmosphere