EARLINET and Satellites: Partners for Aerosol Observations

1. EARLINET and Satellites: Partners for Aerosol Observations Matthias Wiegner Universität München Meteorologisches Institut (Satellites: spaceborne passive radiometry)

2. RTE Radiative transfer equation

3. Radiative transfer equation radiance (upward)

4. Radiative transfer equation source function

5. Radiative transfer equation optical depth (=0 at top at atmosphere) zenith and azimuth angle of radiance

6. Source Fkt. Radiative transfer equation sourcefunction

7. Radiative transfer equation sourcefunction Single scattering albedo

8. Radiative transfer equation sourcefunction phase function

9. RTE Radiative transfer equation

10. Solution Radiative transfer equation Solution

11. Radiative transfer equation Solution contribution from atmosphere

12. Radiative transfer equation Solution contribution from surface

13. Radiance Dependences Radiance at satellite depends on phase function, single scattering albedo air molecules, aerosol particles, cloud droplets size, refractive index, shape; heightdependent and surface properties as the vertical coordinate is the optical depth, radiance also depends on the extinction coefficient

14. Radiance and aerosols: link optical and microphysical parameters of aerosols other atmospheric and surface parameters radiances at satellite sensor

15. Radiance and aerosols: link optical and microphysical parameters of aerosols other atmospheric and surface parameters retrieval algorithms radiances at satellite sensor

16. partnership EARLINET- satellite partnership optical and microphysical parameters of aerosols other atmospheric and surface parameters retrieval algorithms calibrated, validated, complemented radiances at satellite sensor

17. IntroEnde This was the introduction Main topic of my talk How can we establish an „EARLINET-Satellite partnership“?

18. Possible contrib. overview Possible EARLINET contributions Groundtruthing Calibration and validation of satellite data and retrieval algorithms Supply of complementary information Consequence: Definition of the small workpackage „WP8“

19. Possible EARLINET contributions Groundtruthing Calibration and validation of satellite data and retrieval algorithms Supply of complementary information Consequence: Definition of the small workpackage „WP8“

20. Ground truth (cal/val) Use the EARLINET data-base „point by point“ intercomparisons (lidar measurements during an overpass) averaged data (e.g., monthly means)

21. Example (1) Examples of partnership Validation and calibration of MIPAS Focus on ozone (balloon) No aerosols intercomparions yet Status: waiting for overpasses Vincenzo Rizi et al., L'Aquila

22. Examples of partnership Validation and calibration of MIPAS + GOMOS Focus on water vapour and aerosols Few overpasses, but no aerosol data Status: ongoing (waiting) Gelsomina Pappalardo et al., Potenza

23. Examples of partnership Validation and calibration of SAGE Focus on stratospheric aerosols Regular measurements began in summer 02 Status: ongoing, no final results Thomas Trickl et al., Garmisch-Partenkirchen

24. Examples of partnership Validation and calibration of CHRIS Focus on land surfaces Four intensive field experiments scheduled near Gilching Project for On-Board Autonomy Small Satellite Mission Compact High Resolution Imaging Spectrometer MIM in co-operation with:

25. Examples of partnership Goal Full characterization of surface and atmosphere of exactly the same scene Requirements co-incidence, co-location, very small satellite pixel Acquisition mode CHRIS: 18 km swath, 25 m resolution, 19 spectral bands (0.4-1.05 µm), along track (5 angles) Time and place May to August 2002 in Gilching

26. Examples of partnership Results/Conclusions Satellite PROBA encountered severe problems: no data were available in summer 2002. A new intensive field experiment is uncertain MIM & GTCO

27. Possible EARLINET contributions Groundtruthing Calibration and Validation of satellite data and retrieval algorithms Supply of complementary information Consequence: Definition of the small workpackage „WP8“

28. Relevant Aerosol Parameters Relevant (aerosol) parameters Aerosol optical depth/extinction coefficient Aerosol type Aerosol (vertical) distribution Surface albedo Solar zenith angle Fixed wavelength (532 nm)

29. A-Profiles Model calculations Vertical aerosol distribution: 5 cases (1) (2)(3)(4)(5)

30. Sensitivity profiles Change of Radiance as a function of aerosol optical depth for different aerosol profiles fixed aerosol type Difference of isotropic radiance at TOA, rel. to „no aerosol“-case

31. Change of Radiance different aerosol type

32. Change of Radiance different aerosol type

33. Change of Radiance different aerosol type

34. Change of Radiance different aerosol type

35. 2-layer profiles Change of Radiance as a function of aerosol optical depth for different 2-layer aerosol profiles fixed aerosol type

36. Change of Radiance different aerosol type

37. Change of Radiance different aerosol type

38. Change of Radiance different aerosol type

39. Change of Radiance different aerosol type

40. Change of Radiance different layer width

41. Conclusions Simul. Conclusions from simulations Satellite radiances are significantly influenced by aerosols: -- optical depth -- aerosol type -- aerosol profile

42. Examples of partnership Aerosol vertical distribution is hardly retrievable from satellites EARLINET can provide this missing information Vertical aerosol distribution is relevant for local energy budget, hydrological cycle, validation of CTM, ecology,.... ...and satellite validation as well

43. TOMS 10.10.01

49. TOMS 16.10.01

50. Benefit: Results Benefit of partnership Results/Conclusions Aerosol profiles from more than 20 lidar stations, two times a week and for three years are available. Data and instruments have undergone QA. Validation of aerosol retrievals requires a careful selection of time and place, and averaging over reasonable periods. First co-operations are initiated. EARLINET can provide aerosol data that cannot be obtained from passive radiometry.