FLASH-BFLASH-BFLuorescent Advanced Stratospheric Hygrometer(for balloon)

Instrument design.Observations and comparison.

Central Aerological Observatory

Khaykin S., Yushkov V., Korshunov L., Lukyanov A.

FLASH-B instrument

flISource of VUV radiation

h

=121,6 nm (Lyman-α) Н2О

Н(2S)

ОН (А2+)

ОН (Х2П )

PMTН2О + h ОН (А2+) + Н(2S)

Fluorescense ОН (А2+) ОН (Х2П) + h’

Quenching ОН (А2+) + N2, О2 products

Ifl – fluorescense intensity

J - photodissotiation rate

φ= 0,05 - quantum efficiency for excited OH productionА=1,26106 s-1 – Einstein coefficient,

kqair. = 2,310-11 sm3 s-1 – quenching coefficient

of the excited OH in air

300 < λ < 330 nm

2[ ]

[ ]flq

H O J AI

k air A

[ ]qk air A at P > 7 hPa

Photomultiplier

FLASH-B optical layout

Electronic block-layout of FLASH-B

VUV lamp Lyman-alpha 1 KHz 121,6 nm

H2O

OH*

310 nm Interference filter

Photomultiplier

P, T, U

ReceiverModemPC

OSCLampdriver

PMTpower

microcontroller

VAISALARS-80radiosonde

SynchrofilterSynchrodetector Data frame

Compressor

FL

AS

H-B

Vacuum pump

de

hu

mid

ifie

r

H2O

bu

bb

ler

flow

co

ntr

olle

rhomogenizer

Reference dew point mirror hygrometer

MBW 373La

ir o

ut

Calibration facility layout

flow

co

ntr

olle

r

Vacuum chamber

Pressure:3 ..1100 hPa

Temperature:-80 .. +20 0C

WVMR:1 .. 1000 ppmv

Range of water vapour

measurements

Response time

Integration time

Measurement precision

Total uncertainty

Temperature range

Height range

Required power

Weight w/out batteries

Interface card

Radiosonde

0.5...500 ppmv

0.2 sec

4 sec

5.5%

<10 % (1σ) at µ> 3 ppmv

-950C … +400C

7… 35 km

9-30V, 10W max

0.5 kg

Built-in (T-MAX type)

Vaisala RS80-15 A(L)

FLASH-B characteristics

Ny-Alesund

Sodankylä

Lindenberg

Measurement sites since winter 2004

26

24

22

20

18

16

14

12

10

8

heig

ht, k

m

-30 -20 -10 0 10 20 30 mix. ratio diff. (FLASH-NOAA)/NOAA, %

30 Jan 6 Feb 11 Feb 16 Feb 17 Feb 18 Feb 24 Feb mean

difference

Intercomparison of FLASH-B and NOAA/CMDL hygrometers in the stratosphere

Descent data only

Mean difference in the 11,8 – 25,6 km range is: 2.6 ±3.1 % (1 σ)

Large disagreement in the 8,8 – 11,8 km range is caused by the feedback gain change in the NOAA hygrometer

Simultaneous humidity measurements in the troposphere during LAUTLOS

11 February 2004

Simultaneous humidity measurements in the troposphere during LAUTLOS

23 February 2004

FLASH-B & NOAA/CMDL water vapour17 February 2004 Sodankyla

FLASH-B water vapour observations in the presence of PSCs

FLASH-B water vapour Temperature and PSCs thresholds

Ny-Alesund (78,9 N, 11,9 E) 6 January 2005

lidar water vapour

FLASH-B water vapour observations in the presence of PSCs

Ny-Alesund (78,9 N, 11,9 E) 26 January 2005

Forthcoming campaigns with FLASH-B:

SCOUT-AMMA balloon campaign (CNRS) July-August, 2006 West Africa, Niger. up to 10 flights with BKS sonde

STRATEOLE campaign (CNES) August 2006 West Africa, Niger up to 2 flights on long-duration SPB balloons

Future perspectives:

- integration with Swiss Meteolabor radiosonde SRS-34

- Integration with Vaisala RS-92