1. 1. The MPI MAX-DOAS inversion scheme 2. Cloud classification 3. Results: Aerosol OD: Correlation with AERONET Surface extinction: Correlation with Nephelometer Mixing Layer Height: Correlation with Ceilometer NO2 Surface mixing ratio: Correlation with EMPA Mixing Layer Height: Correlation with Ceilometer Inversion of synthetic NO2 SCDs 4. Conclusions Results of the profile inversion from MPI MiniMAX-DOAS measurements during CINDI Thomas Wagner, Reza Shaigan, Steffen Beirle MPI Mainz, Germany

2. Aerosol profiles are parametrised by 3 parameters: following the ideas of Li, X., Brauers, T., Shao, M., Garland, R. M., Wagner, T., Deutschmann, T., and Wahner, A.: MAX-DOAS measurements in southern China: retrieval of aerosol extinctions and validation using ground-based in-situ data, Atmos. Chem. Phys., 10, 2079-2089, 2010. A) vertical optical depth OD (related to total aerosol amount) B) mixing layer height MLH (important atmospheric parameter) C) fraction of total optical depth in boundary layer (allows to adjust vertical profile, depending e.g. on vertical mixing into free troposphere)f = 0.9 90% Constant extinction in ML, exponential decrease above 1. The MPI MAX-DOAS inversion scheme

3. f = 1.5 New (since Nov. 2009): f > 1: Profiles with elevated layers Aerosol profiles are parametrised by 3 parameters: following the ideas of Li, X., Brauers, T., Shao, M., Garland, R. M., Wagner, T., Deutschmann, T., and Wahner, A.: MAX-DOAS measurements in southern China: retrieval of aerosol extinctions and validation using ground-based in-situ data, Atmos. Chem. Phys., 10, 2079-2089, 2010. 1. The MPI MAX-DOAS inversion scheme

4. f = 1.1 New (since Nov. 2009): f > 1: Profiles with elevated layers Aerosol profiles are parametrised by 3 parameters: following the ideas of Li, X., Brauers, T., Shao, M., Garland, R. M., Wagner, T., Deutschmann, T., and Wahner, A.: MAX-DOAS measurements in southern China: retrieval of aerosol extinctions and validation using ground-based in-situ data, Atmos. Chem. Phys., 10, 2079-2089, 2010. 1. The MPI MAX-DOAS inversion scheme Multi-layer aerosols can not be described by this parametrisation

5. Modelling of O4 AMFs: Radiative transfer modelling: Backward Monte-Carlo RTM McArTim (Deutschmann, 2009) Surface albedo: 5% Surface altitude of measurement site Pressure and temperature profiles from US standard atmosphere Greenblatt et al. O4 cross section (corrected by +15% to +25%) Single scattering albedo: 0.95 Asymmetry parameter: 0.68 Number of aerosol scenarios: 172480 MLH (14): 20, 100, 200, 300, 500, 700, 1000, 1200, 1500, 1750, 2000, 2500, 3000, 5000m OD (10): 0.05, 0.1, 0.2, 0.3, 0.5, 0.7, 1.0, 1.5, 2.0, 3.0 f (11): 0.1, 0.2, 0.3, 0.4, 0.5, 0.7, 1.0, 1.1, 1.2, 1.5, 1.8 for 8 elevation angles and 14 SZA / rel. Azimuth angles 1. The MPI MAX-DOAS inversion scheme

6. Parametrisation of NO 2 profiles in a similar way: A) mixing layer height MLH (important atmospheric parameter) B) fraction f of total VCD in boundary layer (allows to adjust vertical profile, depending e.g. on vertical mixing into free troposphere) However, no absolute tropospheric VCD is varied, because NO 2 AMF depends only on relative profile 1. The MPI MAX-DOAS inversion scheme

7. Aerosol inversion: Modelled AMFs are fitted to the measured data in the following way: Measurements: -Subtraction of O4 DSCD at 90° for each elevation sequence -Division by O4 VCD => O4 DAMF Model results: -Subtraction of O4 AMF at 90° for each elevation sequence => O4 DAMF Least squares fit: OD, ML (f: fixed) 1. The MPI MAX-DOAS inversion scheme

8. Result of aerosol fit, Cabauw, 26.6. Sequence 6 Min: 0.0054 for layer height 0.5km, optical depth: 0.23 1. The MPI MAX-DOAS inversion scheme

9. NO 2 inversion: Modelled AMFs are fitted to the measured data in the following way: Measurements: - Subtraction of NO2 DSCD at 90° for each elevation sequence - Division by (shifted) DSCD at 10° Model results (calculated for specific aerosol scenario): - Subtraction of NO2 AMF at 90° for each elevation sequence => NO2 DAMF - Division by DAMFs at 10° Least squares fit: ML (f: fixed) Aerosol parameter from O4 inversion 1. The MPI MAX-DOAS inversion scheme

10. Result of NO2 fit, Cabauw 30.6. sequence 5930.6. sequence 62 Chi2 = 0.05Chi2 = 0.004 1. The MPI MAX-DOAS inversion scheme

11. Classification of the cloud cover using radiance and O4 observations at 90° elevation angle Temporal variation of radiance smooth? yes => Temporal variation of O4 smooth? yes => clear day no => cloudy day O4 absorption largely increased and/or varying rapidly compared to clear day? yes => thick cloud no => thin cloud 2. Cloud classification

12. Day with clear sky 24.6.2009 Cabauw Bruxelles 2. Cloud classification

13. Day with 'thin' clouds 26.06.2009 Cabauw Bruxelles 2. Cloud classification

14. Day with 'thick' clouds 1.7.2009 Cabauw Bruxelles 2. Cloud classification

15. Classification of the cloud cover using radiance and O4 observations at 90° elevation angle O4 AMF – O4 AMF cloudfree 2. Cloud classification

16. A) Typical diurnal cycles B) Aerosol OD: Correlation with AERONET data C) Surface extinction: Correlation with WetNephelometer data D) Mixing Layer Height: Correlation with Ceilometer data 3.1 Results: Aerosols

17. Clear sky cloudy 3.1 Results: Aerosols A) Typical diurnal cycles

18. mostly cloudy Clear sky 3.1 Results: Aerosols A) Typical diurnal cycles

19. All coincidences (half hour averages) 3.1 Results: AerosolsB) Correlation with AERONET OD O4 scaling factor = 1.2 f=0.9

20. Data with layer heigth >= 3km removed 3.1 Results: AerosolsB) Correlation with AERONET OD

21. Also data with chi2 >= 0.04 removed 3.1 Results: AerosolsB) Correlation with AERONET OD

22. Days with (unrealistic) rapid variation of the aerosol OD: 3.1 Results: AerosolsB) Correlation with AERONET OD

23. Data with rapid variation of OD (> 0.5) removed 3.1 Results: AerosolsB) Correlation with AERONET OD

24. Only data for thin clouds 3.1 Results: AerosolsB) Correlation with AERONET OD

25. Only data for clear sky Coincidences only in the morning! (with systematically low MAX-DOAS results) 3.1 Results: AerosolsB) Correlation with AERONET OD

26. Only data for thick clouds 3.1 Results: AerosolsB) Correlation with AERONET OD

27. Correlation with WetNephelometer data from Paul Zieger 3.1 Results: AerosolsC) Correlation with in-situ extinction

28. Correlation with WetNephelometer data from Paul Zieger for different layer heights >1500m: Slope  2 <1500m Slope  1

29. MAX-DOAS aerosol layer height F-value: 0.9 F-value: 1.1 3.1 Results: AerosolsD) Correlation with Ceilometer MLH

30. all data 3.1 Results: AerosolsD) Correlation with Ceilometer MLH

31. only clear sky observations and chi2 < 0.04 3.1 Results: AerosolsD) Correlation with Ceilometer MLH

32. 3.2 Results: NO2 A) Typical diurnal cycles B) Mixing ratio: Correlation with EMPA data C) Mixing Layer Height: Correlation with Ceilometer data D) Inversion of synthetic NO2 DSCDs

33. NO2 mixing ratio for different aerosol f-values thin clouds 3.2 Results: NO2 A) Typical diurnal cycles

34. thin clouds NO2 mixing ratio for different NO2 f-values 3.2 Results: NO2 A) Typical diurnal cycles

35. All coincidences (half hour averages, f-value: 0.9) 3.2 Results: NO2B) Correlation with EMPA mixing ratio

36. All coincidences (half hour averages, f-value: 0.9) Chi2 < 0.04 3.2 Results: NO2B) Correlation with EMPA mixing ratio

37. Only thin clouds 3.2 Results: NO2B) Correlation with EMPA mixing ratio

38. clear sky (only early morning data) 3.2 Results: NO2B) Correlation with EMPA mixing ratio

39. Only thick clouds 3.2 Results: NO2B) Correlation with EMPA mixing ratio

40. Slope of fitR2R2 All data0.720.22 chi2<0.040.740.35 thin clouds0.940.72 clear sky0.450.50 thick clouds2.310.56

41. On some days the NO2 mixing ratios depend strongly on the assumed (relative) aerosol profile. The mixing ratios derived for an elevated aerosol layer (f>1) agree better with the in-situ data. For these observations also the lowest chi2 is found in the aerosol fit (O4 data) for an assumed elevated aerosol layer 3.2 Results: NO2B) Correlation with EMPA mixing ratio

42. Lowest chi2 for elevated aerosol layer Better agreement of NO2 mixing ratio for elevated aerosol layer 3.2 Results: NO2B) Correlation with EMPA mixing ratio

43. 3.2 Results: NO2C) Correlation with Ceilometer MLH Slope of fitR2R2 All data0.48 0.790.13 0.23 chi2<0.040.52 0.900.32 0.39 thin clouds0.56 0.910.34 0.37 clear sky0.80 1.150.52 0.55 thick clouds0.32 0.350.11 0.07 Aerosol fit: f=0.9 f=1.1

44. Fit results for all daily profiles (UV profile 03) F-value Layer height NO2 VCD Chi2 3.2 Results: NO2D) Inversion of synthetic NO2 DSCDs

45. (UV profile 03, all daily profiles) 3.2 Results: NO2D) Inversion of synthetic NO2 DSCDs

46. Results for all UV profiles 3.2 Results: NO2D) Inversion of synthetic NO2 DSCDs

47. -simple MAX-DOAS inversion scheme for UV measurements, based on MC-RTM LUT and least squares fit of simple profile parametrisation -discrimination scheme for clear sky / thin clouds / thick clouds Aerosol inversion: -aerosol OD is reasonable for aerosol f-value of 0.9, clear sky and thin cloud observations; MAX-DOAS aerosol OD about 25% smaller than AERONET -aerosol extinction agrees well with wetnepelometer data for layer heights <1500m -aerosol layer height shows (weak) correlation with ceilometer data only for clear sky 4. Conclusions

48. NO2 inversion: -NO2 mixing ratio agrees well with in-situ observations for clear sky and thin cloud observations; only weak dependence on aerosol f-value; almost no dependence on NO2 f-value -NO2 layer height shows reasonable correlation with ceilometer data for clear sky and thin cloud data Inversion of synthetic NO2 SCDs -good agreement found for NO2 profiles for low and high aerosol load -for some profiles rather large deviations during the day 4. Conclusions

50. different scaling factors for the O4 cross section (observations for thin clouds) +20 % seems to be the best choice 3.1 Results: AerosolsB) Correlation with AERONET OD +15 % +20 % +25 %

51. Correlations for different f-.values (observations for thin clouds) 0.9 seems to be a good choice 3.1 Results: AerosolsB) Correlation with AERONET OD

52. Aerosol extinction for different aerosol f-values thin clouds 3.1 Results: Aerosols

53. clear sky cloudy sky 3.1 Results: Aerosols Aerosol extinction for different aerosol f-values

54. for different aerosol f-values (thin cloud data) 3.2 Results: NO2B) Correlation with EMPA mixing ratio

55. for different NO2 f-values (thin cloud data) Almost no dependence on NO2 f-value 3.2 Results: NO2B) Correlation with EMPA mixing ratio

56. Day with better agreement for elevated layer (some periods) Lowest chi2 for elevated aerosol layer Better agreement of NO2 mixing ratio for elevated aerosol layer 3.2 Results: NO2B) Correlation with EMPA mixing ratio

57. (all data, NO2 f-value: 0.9) 3.2 Results: NO2C) Correlation with Ceilometer MLH

58. NO2 Chi2 <0.04 3.2 Results: NO2C) Correlation with Ceilometer MLH

59. Only thin clouds 3.2 Results: NO2C) Correlation with Ceilometer MLH

60. Only clear sky 3.2 Results: NO2C) Correlation with Ceilometer MLH

61. Only thick clouds 3.2 Results: NO2C) Correlation with Ceilometer MLH