A prototype optoelectronic hygrometer, based on absorption of laser light tuned to a specific
rovibronic absorption line of H2O at 1364.68961 nm is described. Target application is meteorol-
ogy, in particular precise and fast measurements of small-scale humidity fluctuations in turbulent
atmospheric flows. Tests of the prototype instrument performed in the atmospheric boundary
layer have proven the advantage of this optoelectronic sensor over typical, commercially available
UV hygrometers designed for similar applications.