The FLASH instrument for water vapour measurements on board of high altitude airplane

A fluorescent airborne stratospheric hygrometer (FLASH) for precise water vapor measurements on board a high-altitude airplane in the upper troposphere and the lower stratosphere has been developed and produced at the Central Aerological Observatory. The range of measured water vapor concentrations is 0.5-300 ppmv at altitudes of 8-21 km. The results of laboratory tests of the instrument are compared to the data of the other hygrometers. Some results of water vapor measurements on board the Geofizika M55 high-altitude airplane in different regions of the Earth are presented.