Report on the successful TRIPLE flight from Esrange on 27 January 2000

by Fred Stroh

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TRIPLE team by the gondola prior to launch on 27 January 2000. From left: Fred Stroh, Jochen Bartels, Bärbel Vogel, Erich Klein, Cornelius Schiller. In front: Melanie Müller.
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The auxilliary balloons are inflated and the payload floats just above the ground.
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Three members of the TRIPLE team are waiting while the main balloon is being inflated. The balloon has just been launched.
The auxilliary balloons have been separated from the payload. The main balloon with the payload is on the way up to the stratosphere.
During the ballloon flight the TRIPLE team are watching the flow of data and operate the cryosamplers by "telecommande".

Instruments and people:

1. ClO/BrO instrument:

Technique: Chemical conversion resonance fluorescence: ClO and BrO are chemically converted to the respective atoms by adding NO to a laminar flow of ambient air. The atoms are detected downstream by resonance fluorescence in the vacuum UV spectral region.
Fred Stroh, Forschungszentrum Jülich, Jülich, Germany (
Coworkers: Bärbel Vogel

2. Fluorscent in-situ hygrometer (FISH):

Technique: Water molecules are photolysed by Lyman-alpha radiation in an air flow and the fluorescence of the OH product radical is observed.
Cornelius Schiller, Forschungszentrum Jülich, Jülich, Germany (
Jürgen Beuermann

3. Cryogenic whole air sampler (BONBON):

Technique: Air samples are collected by opening and closing evacuated stainless steel cylinders immersed in liquid neon. Analysis for CH4, N2O, CFCs, SF6, CH3Br, several Halons, and many other species are carried out by GC and GC/MS.
PIs: Melanie Müller, Andreas Engel, University Frankfurt, Germany, (,
Coworkers: Bill Sturges, University of East Anglia, Norwich, UK

4. Filter radiometer:

(failed in flight due to a battery problem)

Technique: Actinic flux in two spectral regions J(NO2) and J(O(1D)) is measured through optical filters both upward and downward facing direction.
PI: Cornelius Schiller, Forschungszentrum Jülich, Jülich, Germany (

5. Aerosol size distribution:

Technique: Optical particle counter
PIs: Henri and Joelle Ovarlez, LMD, Palaiseau, France (

6. ECC ozone sonde

Signal was jammed during flight due to an unknown second transmitter.

Additional technical staff of FZ-Jülich:

Erich Klein, Jochen Bartels, Vicheith Tan*, Armin Afchine*
(* not present at the campaign)


A first try to launch TRIPLE on Jan-19th failed due to a problem with the main balloon just prior to take-off. Finally TRIPLE was launched on Thursday 27 January at local noon. All instruments except the radiometers and an on-board ozonesonde worked during the flight. The payload was recovered in good shape from eastern Finland. Data analysis for the in-situ instruments is in progress. The cryo-sampler is currently transported back to Frankfurt for laboratory analysis of 15 air samples taken during the flight.

Flight profile:

The balloon ascended to an altitude of ca. 26km (19hPa) and then slowly descended to 22km (37hPa). There a float occurred covering the solar zenith angle regime from 92 to 97 degrees to measure the variation of ClO and BrO. Then the balloon descended slowly to around 10km (250hPa) where separation occurred. The balloon was excellently piloted by the CNES team.

Preliminary results:

Preliminary ClO/BrO, H2O, and aerosol size distribution profiles have been calculated. A layer of enhanced ClO was observed around 30hPa (peak mixing ratio of ca. 1300pptv). During sunset average ClO mixing ratios between 600 and 200pptv were observed. No obvious sign of dehydration was observed in the data. The aerosol measurement indicates very low particle concentrations at pressures less than 50hPa.

This page was updated on 6 February 2000 by Geir Braathen, NILU.