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