1. Page 1 Validation by Balloons and Aircraft - ESRIN - 9– 13 December 2002 Observations of aerosol and clouds obtained during the M-55 Geophysica ENVISAT Validation Campaigns Marco Cacciani University of Rome “La Sapienza”, Italy Stephan Borrmann University of Mainz, Germany Francesco Cairo ISAC-CNR, Italy Giorgio Fiocco University of Rome “La Sapienza”, Italy Anastasios Kentarchos ERS-srl, Italy Valentin Mitev Observatoire Neuchatel, Switzerland Leopoldo Stefanutti Geophysica-GEIE, Italy

2. Page 2 Validation by Balloons and Aircraft - ESRIN - 9– 13 December 2002 Summary Review of the instruments and performances Results of the July campaign in terms of total backscatter ratio, cloud top altitude, optical depth Internal consistency of the data and comparison with ground-based lidar measurements Samples of the results obtained during the October campaign Conclusions

3. Page 3 Validation by Balloons and Aircraft - ESRIN - 9– 13 December 2002 Table I: Instruments, flights and performances

4. Page 4 Validation by Balloons and Aircraft - ESRIN - 9– 13 December 2002 Figure 1. July 15 flight path

5. Page 5 Validation by Balloons and Aircraft - ESRIN - 9– 13 December 2002 FIGURE 2. First aerosol flight (July15); top:total aerosol backscatter ratio vs. time and altitude (the color bar on the left side represents the typical error in the value of the backscatter ratio; the flight altitude is indicated by a black line); middle: cloud top altitude (±30 m); bottom: thin clouds optical depth at 532 nm (error bars are shown; red color is used when a second layer is present in the same profile).

6. Page 6 Validation by Balloons and Aircraft - ESRIN - 9– 13 December 2002 Figure 3. Backward isentropic trajectories starting from the lowest point of the dive and passing over Lampedusa at different times. Numbers refer to the number of day. The July 15 flight path is shown with a color scale proportional to the altitude Figure 4. Backscatter ratio vertical profiles observed by ABLE at the lowest point of the dive (lines) and by the Lampedusa Lidar in coincidence with the air mass passage (dots)

7. Page 7 Validation by Balloons and Aircraft - ESRIN - 9– 13 December 2002 Figure 5. July 18 flight path

8. Page 8 Validation by Balloons and Aircraft - ESRIN - 9– 13 December 2002 Figure 6. Second aerosol flight (July 18). Same as figure 2.

9. Page 9 Validation by Balloons and Aircraft - ESRIN - 9– 13 December 2002 Figure 7. Second aerosol flight (July 18): comparisons between observations of the total backscatter ratio obtained by in situ (MAS) and remote sensing (MALdown) instruments. Figure 8. Second aerosol flight (July 18). Comparison between ABLE and MALdown observations; left: in the presence of Saharan dust; right: in the presence of high and middle level tropospheric clouds. Cloud top altitude: ABLE-MAL mean difference= (-5.5±3.5) m

10. Page 10 Validation by Balloons and Aircraft - ESRIN - 9– 13 December 2002 Figure 9. First aerosol flight (October 11). Plot of the aerosol backscatter ratio at 1064 nm (ABLE) and at 532 nm (MAL) vs. time and altitude. Preliminary results.

11. Page 11 Validation by Balloons and Aircraft - ESRIN - 9– 13 December 2002 Conclusions During the July campaign observations of Saharan dust and tropospheric clouds were carried out using remote sensing and in situ techniques. Values of the cloud top altitude and visible optical depth are available to perform the validation of the ENVISAT aerosol products. Profiles of the aerosol extinction coefficient can be retrieved by the aerosol backscatter ratio profiles. Inter-comparisons show a good consistency of the results obtained by the onboard instruments as well as the agreement with ground- based observations. Preliminary analysis of the results obtained during the October campaign: –very good performances of almost all instruments; –aerosol data for validation will be available in both types of flight (aerosol and chemical); –day-time observations are directly usable for the validation.