1. Acknowledgements : R. Bevilacqua and NRL POAM III Science Team
Validation of ENVISAT Products using POAM III O3, NO2, H2O and O2 profiles
Authors: F. GOUTAIL, A. BAZUREAU
Description of POAM instrument
Constituents measured
List of profiles available
Example of Profiles
Comparison with GOMOS
Conclusion
Acknowledgements : R. Bevilacqua and NRL POAM III Science Team

2. Description of POAM III Instrument
Launched on SPOT 4 satellite (CNES) on March 1998
Heliosynchronous quasi-polar orbit : HN (sunrise) – HS (sunset)
14 profiles/ day in each hemisphere (at the same latitude)
Between 54 – 71 °N
Between °S
Solar occultation technique in UV- visible band
Vertical profiles of O3, NO2, H2O, O2
Vertical resolution
1 km for O3
1.5 to 2.5 km for NO2 HN
varying with season HS

3. POAM III Validation results

4. List of profiles available
Since July 2002
Monthly “package” for each hemisphere
from July to November 2002.
Profiles of O3, NO2, H2O, O2 and aerosol extinction coefficient at 1018 nm
Profiles of Pressure and Temperature from NMC analysis
Very soon : December POAM III profiles
Future developments : all aerosol extinction coefficient profiles and …
all errors bars (for all constituents)
- POAM III HDF data Version 2 -

5. Example of profiles POAM III and GOMOS

6. Comparisons with GOMOS : Southern Hemisphere - July 2002
Coincidence criterions :
time < 24 hours
distances < 800 km
20 “matches” found :
Eta Tau (2.8)
Alp Tau (0.8)

7. Comparisons with GOMOS : Southern Hemisphere - July 2002
Pressure and temperature profiles : NMC analysis versus ECMWF
Analysis conducted for each star

8. Comparisons with GOMOS : Southern Hemisphere - July 2002
Constituents profiles comparisons :

9. Comparisons with GOMOS : Southern Hemisphere - July 2002
Constituents profiles comparisons :

10. Comparisons with GOMOS : Northern Hemisphere - September 2002 on work
Coincidence criterions :
time < 24 hours
distances < 800 km
47 “matches” found
49 Del Cap (2.8)
20 distances GOMOS / POAM III
< 400 km

11. Comparisons with GOMOS : Northern Hemisphere - September 2002
Pressure and temperature profiles : NMC analysis versus ECMWF model

12. Comparisons with GOMOS : Northern Hemisphere - September 2002
Constituents profiles comparisons :

13. Comparisons POAM III / GOMOS : SUMMARY
Comparisons of pressure and temperature relative difference profiles for each star :

14. Comparisons POAM III / GOMOS : SUMMARY (2)

15. Conclusions
Comparison and validation programs are now ready for ENVISAT instruments validation
Reading PDS format programs not yet well mastered (several problems with Enviview)
Extraction of ENVISAT instrument profiles still hard working …
Waiting for GOMOS aerosol extinction coefficients profiles
Waiting for new GOMOS processing for O3, O2, NO2, H2O
MIPAS profiles coincident with POAM III available ?
First SCIAMACHY profiles are waited in January 2003