1. ENVISAT VALIDATION AT TROPICS J. P.POMMEREAU, A. GARNIER, F. GOUTAIL, F. BORCHI Service d ’Aéronomie CNRS, Verrières le Buisson, France A. HERTZOG and F. VIAL Laboratoire de Météorologie Dynamique, Palaiseau, France N. R. P. HARRIS, J. PYLE, R. L. JONES, A. ROBINSON, G. HANSFORD Dept of Chemistry, University of Cambridge A. BUIVAN Instituto de Pesquisas Meteorologicas Bauru, SP, Brazil G. LETRENNE CNES Toulouse, France ESABC PARIS 8 Nov 2002

2. OUTLINE SAOZ short and long duration balloon flights at the tropics : example of past results Plan for February - Mars 2003

3. PAST EXPERIENCE IN BRAZIL Nov 1997 EC Stratospheric Regular Soundings Four short duration 10 ZL flights SAOZ, SAOZ-BRO, DESCARTES, LABS, OPC Nov 2000 and February 2001 CNES technical MIR flights + two ZL

4. IPMet balloon facility at Bauru-SP (Brazil, 22°S) IPMet : Institute of Meteorological Research of the State University of Sao Paulo (UNESP) Bauru Sao Paulo HIBISCUS Meteorological support Weather radar Radiosondes station Balloon launch facility Airport

5. Stratospheric Regular Sounding November 1997 SAOZ / SAOZ-BrO flight

6. February 2001 : SAOZ-MIR test flight Launched from Bauru (Brazil), Feb 13, 2001 34 days flight, 2 circum-navigation Validation of measurements at Reunion Island (lidar, sondes) Recovered in Argentina Bauru Reunion Is. Salta

7. SAOZ-MIR test flight Instrumentation (60 kg total) : 3 independent payloads - SAMBA: GPS, T, P, IR radiometer, control and safety - SAOZ : Solar occultation Uv-Visible spectrometer: O3, NO2, O2, O4, H2O, atmospheric extinction - RUMBA : GPS, T, high temporal resolution Pressure

8. Ozone variability Overpass over Reunion Island SAOZ-MIR, lidar and sondes Longitudinal variability 3% in LS above 20 km (little influence of horizontal transport) 30% in UT strong horizontal exchange (highly pv correlated)

9. Nitrogen Dioxide Secondary maximum at 22-24 km Highly variable in both UT and LS Minimum concentration and diurnal variation at Tropopause Requires: Local source of NOx Electric discharges? Precipitation of charged particles in Atlantic anomaly? NOx gas phase chemistry different from currently known Heterogneous NOx/NOy reactions at tropopause

10. Example of Satellite Validation MIR and HALOE variability along latitude circle Tropopause HALOE O3 and NO2 perturbed by clouds below 22 km Measurements not reliable below tropopause

11. Clouds Observations Optical Extinction at 550 nm Global IR Radiometer

12. Cirrus and sub-visual cirrus Higher and thicker above continental areas

13. Permanent ultra-thin tropopause Haze - Ubiquitous at T<200K - 1 part./Cc (r=1µm) Size distribution ? Formation ? Photochemical impact ?

14. Electrical discharges in the stratosphere Frequency over high convective area ? Impact on stratospheric chemistry ? Electrical impact of payloads and balloon around 20-22 km 60 km 20 km Blue Jet at Arecibo Pasko et al., Nature, March 02 LIS Flashes DJF

15. ENVISAT VALIDATION CAMPAIGN FEBRUARY 2003 TWO 10 ZL BALLOONS (ONE SUNSET, ONE SUNRISE) SAOZ (O3, NO2, H2O, clouds), SAOZ-UV (BrO, OClO ? CH2O?), DIRAC GC (N2O, CFC), DESCARTES (SLS, O3 SSS, H2O SAW, Micro-Lidar TWO MIR (2 months autonomy) Met, Global IR radiometer, lightning detector. 1st : regular SAOZ (O3, NO2, trop. H2O, extinction at 550 nm); 2nd: SAOZ H2O (O3, NO2, strat H2O, extinction at 1 µm) RADIOSONDES RS-90, O3 SSS, O3 ECC, H2O SAW, H2O H-Humicap