FLASH-B FLASH-B FLuorescent Advanced Stratospheric Hygrometer (for balloon and aircraft) Instrument design. Observations and comparison. Central Aerological Observatory Khaykin S., Yushkov V., Korshunov L., Lukyanov A. ISSI”Atmospheric Water Vapour” Febr.2008 Bern

Aircraft FLASH-B uses closed optical cell Day&night time mesurements Balloon FLASH=B uses open optical cell Night time measurements Short balloon & long duration balloon ISSI”Atmospheric Water Vapour” Febr.2008 Bern

FLASH-B instrument ISSI”Atmospheric Water Vapour” Febr.2008 Bern

Source of VUV radiation h =121,6 nm (Lyman-α) Н2ОН2О Н( 2 S) ОН (А 2  + ) ОН (Х 2 П ) PMT Н 2 О + h  ОН (А 2  + ) + Н( 2 S) Fluorescense ОН (А 2  + )  ОН (Х 2 П) + h ’ Quenching ОН (А 2  + ) + N 2, О 2  products I fl – fluorescense intensity J - photodissotiation rate φ= 0,05 - quantum efficiency for excited OH production А=1,26  10 6 s -1 – Einstein coefficient, k q air. = 2,3  sm 3 s -1 – quenching coefficient of the excited OH in air 300 < λ < 330 nm at P > 7 hPa [H 2 O] I fl = S cal [ air]

Photomultiplier FLASH-B optical layout

Electronic block-layout of FLASH-B VUV lamp Lyman-alpha 1 KHz 121,6 nm H 2 O OH* 310nm Interference filter Photomultiplier P, T, U Receiver Modem PC OSC Lamp driver PMT power microcontroller VAISALA RS-80 radiosonde Synchrofilter Synchrodetector Data frame ISSI”Atmospheric Water Vapour” Febr.2008 Bern

Compressor FLASH-B Vacuum pump dehumidifierH 2 O bubbler flowcontroller homogenizer Reference dew point mirror hygrometer MBW 373L air out Calibration facility layout flow controller Vacuum chamber Pressure: hPa Temperature: C WVMR: ppmv

FLASH-B characteristics 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 ppmv 0.2 sec 4 sec 5.5% 3 ppmv C … C 7… 35 km 9-30V, 10W max 0.5 kg Built-in (T-MAX type) Vaisala RS80-15 A(L) ISSI”Atmospheric Water Vapour” Febr.2008 Bern

Ny-Alesund Sodankylä Lindenberg Measurement sites since winter 2004

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

Comparison of in-situ balloon-borne and remote microwave water vapour measurements B. Deuber et al., 2005, JGR Comparison of MIAWARA (solid grey), NOAA(dashed black)/CU- CFH (dashed-dotted black) and FLASH-B (solid black) (balloon descent) profiles for different days. The black dots are measurements by NOAA/CU-CFH which were not considered due to remaining wet contamination from the ascent or instrumental failure. The balloon profiles were reduced to the microwave retrieval grid using the Curtis - Godson equation. The CU-CFH sonde was flown on Feb- 15 and Feb-25, on the other flights the older NOAA version was used.

Simultaneous humidity measurements in the troposphere during LAUTLOS 11 February 2004

Simultaneous humidity measurements in the troposphere during LAUTLOS 23 February 2004

Water vapour profiles inside, otside and at the edge of polar vortex during LAUTLOS campaign (Sodankyla, Jan-Feb 2004).

Water vapour soundings at the Arctic stations in 2006/2007

Water vapour soundings in the tropics in 2006 (SCOUT-AMMA)

SCOUT-AMMA balloon campaign. Local convection on 23 August Hydration of LS by ice geysers C-band radar cloud tops height at 16:51 UT on 23 August, two hours before the sounding from Niamey

NASA TC4 campaign, Costa-Rica, 10 0 N, August 2007 (sonde programme): simulataneous measurements of water vapour and ozone by FLASH-B and CFH hygro-sondes.

NASA TC4 campaign, Costa-Rica, 10 0 N, August 2007 (sonde programme): simulataneous measurements of water vapour and ozone by FLASH-B and CFH hygro-sondes. Comparison between FLASH-B and CFH H 2 O descent profiles Mean relative difference in the 10% range

Comparison between FLASH-B and ECMWF Arctic ISSI”Atmospheric Water Vapour” Febr.2008 Bern

Comparison between FLASH-B and ECMWF Tropics ISSI”Atmospheric Water Vapour” Febr.2008 Bern

incl. convection tropopause (17 km): cold point and cold trap SCOUT-O3 Darwin, Australia, 12 0 S, November 2005 H 2 O and O 3 measurements with FISH on board M55-Geophysica Courtesy of C. Schiller

SCOUT-O3 Darwin, Australia, 12 0 S, November 2005 H 2 O and O 3 measurements with FLASH and FOZAN on board M55-Geophysica 16 November Well mixed dry air between LRT and CPT CPT LRT No signs of hydration in LS above Hector Warmer T and higher O 3 in LS above Hector

SCOUT-O3 Darwin, Australia, 12 0 S, November 2005 H 2 O and O 3 measurements with FLASH and FOZAN on board M55-Geophysica H 2 O, temperature and O 3 profiles above Darwin No signs of hydration in LS above Hector Enhanced ozone inside Hector Dry and mixed TTL with H 2 O amounts controlled by saturation at CPT

Ice geyser hydration across the tropopause may be the dominant factor controlling water vapour at global scale in the stratosphere. Concluding remarks WVMR observations above Darwin do not show strong signatures of LS hydration above Hector H 2 O, O 3 and particles measurements above Africa during monsoon season strongly indicate that convective overshooting above continental region hydrates lower stratosphere Ice geyser hydration across the tropopause may be the dominant factor controlling water vapour at global scale in the stratosphere.

FLASH-B on board long duration super pressure balloon CNES SPB mission in Esrange, Kiruna, Sweden (March 2007) 1 st day of flight – contamination from the payload 5 th day of flight – dry payload, no contamination

FLASH-B on board long duration super pressure balloon CNES SPB mission in Esrange, Kiruna, Sweden (March 2007) 12 m 2 CNES SP balloon launched from Esrange on days flight around the pole inside vortex FLASH-B in the bottom of flight train 15 minutes measurements every 2 hours during night time Landing and recovery in Sweden

THANK YOU

Simultaneous humidity measurements in the troposphere during Scout-AMMA

Water vapour soundings at the Arctic stations in 2004/2005

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

lidarwater vapour FLASH-B water vapour observations in the presence of PSCs Ny-Alesund (78,9 N, 11,9 E) 26 January 2005