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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.

DESCRIPTION

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.

METHOD

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

SPECIFICATIONS
Comparisons

Intercomparisons

FLASH-B performance and metrological characteristics have been validated in a large number of field intercomparisons (NOAA-CMDL, CFH, FPH, Pico-SDLA etc.)

There are a lot of publications

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

Thanks! Message sent.

CONTACT
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