E. Kyrl1, J. Tamminen 1, V. Sofieva 1, - PowerPoint PPT Presentation

Title: E. Kyrl1, J. Tamminen 1, V. Sofieva 1,


1
GOMOS/Envisat overview
E. Kyrölä(1), J. Tamminen (1), V. Sofieva (1),
J. L. Bertaux (2), A. Hauchecorne (2), F.
Dalaudier (2), D. Fussen (3), O. Fanton d'Andon
(4), G. Barrot (4), M. Guirlet (4), T. Fehr (5)
THE GOMOS TEAM (1) Finnish Meteorological
Institute, Helsinki, Finland (2) Service
d'Aéronomie du CNRS, Verrieres le Buisson Cedex,
France (3) Institut d'Aeronomie Spatiale de
Belgique, Brussesls, Belgium (4) ACRI-ST, Sophia
Antipolis, France (5) ESA/ESRIN, Frascati, Italy
2
Contents

• Introduction Principle, instrument, processing
• Performance Instrument status
• Performance Coverage (global, time, altitude)
• GOMOS data 2002-2005 Global profiles
• Summary

3
Global Ozone Monitoring by Occultations of Stars
Iref(l)
Iocc(l)
Vertical profiles with
Global coverage
Iocc(l)
Self-calibration
T(l)
Iref(l)
4
GOMOS instrument optics and detectors
2 photometers 1 kHz HRTP
650-700 nm
625-959 nm
star tracker 100 Hz
470-520 nm
grating
grating
1.2 nm
0.2 nm
0.2 nm
2 Hz
250 nm
675 nm
926-952 nm
756-773 nm
O3, NO2, NO3, air, aerosols
H2O
O2
5
GOMOS data processing (night)
upper limb
UV-VIS IR CCDs
star
Photometers
lower limb
Trans mission
Time series
Spectral inv.
Dev.
scint. corr.
Slant columns
HRTP
Turbu- lence
Vertical inv.
Vertical profiles
O3, NO2, NO3, air, aerosols,H2O,O2
6
GOMOS data processing (day)
upper limb
star limb
lower limb
limb rem.
Trans mission
Limb
Spectral inv.
Slant columns
Limb inv.
Vertical inv.
Dev. (FMI OSIRIS)
Vertical profiles
O3, NO2, aerosols
7
(No Transcript)
8
Instrument performance status

• CCDs sensitive to proton precipitation more
  frequent calibration cooling
• no science impact so far future instrument
  design. A new report by M. Dobber (KNMI) on
  GOMOS, OSIRIS, OMI CCDs.
• 2. Pointing system has failed twice
• May-June, 2003 Recovery by redundancy
• Jan-Aug, 2005 Recovery by the limitation of the
  pointing azimuth range -10...90 -5...25 deg.
  At least 65 of the measurements secured.
• IR2 spectrometer PRNU calibration problem H2O
  quality
• 4. Limb spectra suffer from stray light and
  saturation

9
Failure 1
Failure 2
10
GOMOS day and night coverage (2003)
polar night
polar night
Night (45) solar zenith 108-180 deg
Day (45) solar zenith 0-90 deg
Twilight (10)
11
Local time coverage 20S-20N
zen108 deg
zen 12
Examples of results
Reprocessed 2002-2005 data Version 6.0cf (IPF
5.0) Neutral density fixed ECMWF More than
300 000 measurements
13
Retrieved species with altitude ranges
100
90
80
70
SPE
60
50
x
40
30
?
20
10
14
GOMOS profile products

• Altitude knowledge
• Vertical resolution
• Statistical accuracy
• Stability
• Night coverage
• Global coverage
• Simple retrieval
• Poor S/N ratio
• 200 sources, 2400 instruments

15
Validation with ground based instruments
by Y. Meijer, KNMI
16
GOMOS-MIPAS comparison
From Verronen et al., Adv. Space Res., 2005
17
Stratosphere O3 number density in 2003 (1012cm-3)
18
Mesosphere log10 O3 mixing ratio in 2003
19
NO2 number density (109cm-3) in 2003
20
NO3 number density (107cm-3) in 2003
21
Aerosol extinction in 2003
22
Ozone mixing ratio(20 days median) in 20S-20N
23
NO2
50N - 90N
90S - 50S
24
GOMOS summary 2002-2006
More than 300 000 measurements (day night)
All data reprocessed Ozone validation
successful Comparisons OSIRIS (O3), MIPAS (O3,
NO2) Comparisons to ROSE-models Ozone, NO2,
NO3, aerosol climatologies Na, OClO
detection Proton events-NOx-HOx-ozone
Stratospheric turbulence