Fluorescence
Lyman-Alpha
Stratospheric
Hygrometer
for Balloon
(FLASH-B)
Description
The fluorescent hygrometer FLASH-B is a compact and lightweight sonde for in situ balloon water vapor measurements in the upper troposphere and stratosphere.The instrument uses the open layout, where the optics is looking directly into the outside air.
The source of Lyman-alpha radiation is a hydrogen discharge lamp while the detector of OH fluorescence at 308 -316 nm is a photomultiplier run in photon counting mode. The intensity of the fluorescent light as well as the instrument readings is directly proportional to the water vapor mixing ratio under stratospheric conditions with negligible oxygen absorption.
Method
The instrument is based on the fluorescent method (Kley and Stone, 1978; Bertaux and Dellanoy, 1978), which uses H2O molecules photodissociation at a wavelength l=121.6 nm (La - hydrogen emission) followed by the measurement of the fluorescence of excited OH radicals. The source of Lyman-alpha radiation is a hydrogen discharge lamp while the detector of OH fluorescence at 308 -316 nm is a photomultiplier run in photon counting mode. The intensity of the fluorescent light as well as the instrument readings is directly proportional to the water vapor mixing ratio under stratospheric conditions with negligible oxygen absorption.
Specifications
Range of measurement 0.5...1000 ppmv
Resolution time 1 sec
Integration time 4 sec
Precision 5.5%
Total uncertainty <10 % (1σ) at µ> 3 ppmv
Vertical resolution ~ 50 m (descent in UTLS)
Temperature range -95 C … +40 C
Pressure range 300… 5 hPa
Required power 9-18V, 1 W max
Weight (w/o batteries) 500 gr
Size Insulation Box 265 x 155 x 105 mm
Flight weight 1000 gr
Interface to Vaisala RS92, RS41
Meisei RS-06G,
Meteolabor SRS34
Protocol Xdata 20 byte/sec
CONTACTS
Federal Service for Hydrometeorology and Environmental Monitoring of Russia
CENTRAL AEROLOGICAL OBSERVATORY
Department of Upper Atmosphere Physics
3, Pervomayskaya str., Dolgoprudny,
Moscow region,
141700, Russia
Tel:+7 495 408 61 50
Tel: +7 916 149 39 04
E-mail: alykov@mail.ru
http://www.flash-b.ru http://www.flashb.ru http://www.flash-b.info