LONG DURATION FLIGHTS OF BALLOONS FOR THE STUDY OF STRATOSPHERIC CHEMISTRY IN THE FRAME OF THE TARAN

1
LONG DURATION FLIGHTS OF BALLOONS FOR THE STUDY
OF STRATOSPHERIC CHEMISTRY IN THE FRAME OF THE
TARANIS PROJECTLPCE Gwenaël BERTHET CETP
Elena SERAN Valéry CATOIRE Michel GODEFROY
Michel CHARTIER Francis VIVAT Nathalie
HURET Dominique LAGOUTTE CESR Pierre-Louis
BLELLY

François LEFEUVRE
Jean-André SAUVAUD Aurélie
MARCHAUDON
François FORME Jean-Louis PINCON Claude
ROBERT Michel TAGGER
2

• This is a starting project, linked with TARANIS
• Measurements from balloons on stratospheric
  chemistry, but also on TGF, on electric fields,
  and on TLE

3

• Stratospheric chemistry context
• Production of NOx (NONO2) in the upper
  stratosphere by high energy phenomena
• For example after strong solar eruption (high
  energy protons)
• Detection using satellite instruments over polar
  cap

GOMOS onboard Envisat Nighttime measurements
4

• Smaller enhancements expected during TLE/TGF
  events
• Satellite data are difficult to use for detection
  of such
• local NOx enhancements
• - Line of sight of several hundreds of km in the
  stratosphere ( dilution of the absolute values
  of the enhancements)
• - Need of nighttime measurements (long
  persistence of the enhancements due to the
  absence of photochemistry)

5

• Best solution Use of instruments onboard
  stratospheric balloons up to altitude of 40 km
• Remote sensing and in-situ measurements
• Gondolas up to few hundreds of kg
• Need of long duration flights
• (at least several days) to stay close
• to thunderstorm areas

6

• At present, long duration flights (several days
  to several weeks) with
• MIR (infrared balloons)
• BP (pressurized balloons)

7

• Problems
• - scientific payloads of few tens of kg maximum
• - need of using chemistry instruments of around
  100 kg and TGF (and TLE) instruments of several
  tens of kg
• - flights not possible above storms and large
  cloud expanses
• Solution
• use of conventional stratospheric balloons (BSO)
• - flights of at least 10 days
• - payloads up to 200 kg
• - flight altitude up to 40 km

8

• We propose gondolas with different instruments
  for
• - Measurements of stratospheric species by
  in-situ and remote sensing techniques
• - Detection of terrestrial gamma rays flashes
• - Electric fields measurements (to be defined )
• - Detection of TLE by fast cameras

9

• Terrestrial Gamma-ray Flashes
• Balloons can allow us to perform in situ
  measurements
• Between 20 and 40 km, good probability of
  detecting TGF
• Use of an already existing balloon-borne
  instrument (that needs to be improved )

10

• TLE
• Fast cameras

• Survey of lightning TLE
• 3D
• spatial resolution of 2 (up to 0.5)
• temporal resolution/exposition 1 ms
• dynamics 0.01-100 MR
• wave length 380-850 nm

ATLEC Atmospheric Transient Luminous Event
Camera
LONG DURATION FLIGHTS
11

• Stratospheric chemistry
• SPIRIT instrument under development
• In-situ measurements of NO2 and tracers (CH4,
  N2O to identify the origin of the air masses)
• Infra red tunable laser diode

Mixing ratios
Typical NO2 measurements above Brazil
Technique of measurement
12

• SALOMON-JN
• Remote sensing measurements using Moon and Sun as
  light sources (line of sights at least ten times
  smaller than for satellite instruments)
• Improvement (under development) of the already
  existing SALOMON instrument

SALOMON NO2 measurements
13

• In-situ measurements
• accurate estimation of the concentration, but
  lower probability to cross a local enhancements
• Remote sensing-measurements
• higher probability to detect the enhancements but
  underestimation of the absolute values of the
  concentrations (dilution effect)
• Need to combine the two techniques (by using
  the two instruments in the same gondolas or in
  different gondolas)

14

• Strategy of measurements
• Choose of the launching site
• Safe tropical regions with possibility of CNES
  installation
• North Brazil (Teresina) ?
• Kourou (French Guyana) ?

15

• Needs of technical flights before the launch of
  TARANIS to test the long duration balloons and
  the new instruments
• Launch during weak stratospheric winds in order
  to stay close to the launching site (better
  probability of safe recovery)
• At least two different gondolas (risk of loosing
  the payloads) ?
• 1 campaign per 18 month ?

16

• Project under construction
• Submission of the project to the CNES balloon
  workshop
• (PAU September 2008)
• Final project submitted to CNES in 2009
• New contributions welcome, including ground-bases
  measurements