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New Developments in AERONET aerosol retrievals

Oleg Dubovik (Code 614.4 ). New Developments in AERONET aerosol retrievals. Outlines: Improving operational retrieval software Aerosol particle non-sphericity Inversion of combined AERONET/satellite observations. INPUT of Forward Model. Aerosol characterization form AERONET retrievals.

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New Developments in AERONET aerosol retrievals

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  1. Oleg Dubovik(Code 614.4) New Developments in AERONET aerosol retrievals Outlines: • Improving operational retrieval software • Aerosol particle non-sphericity • Inversion of combined AERONET/satellite observations

  2. INPUT of Forward Model Aerosol characterization form AERONET retrievals Complex Refractive Index at l = 0.44; 0.67; 0.87; 1.02 mm Particle Size Distribution: 0.05 mm ≤ R (22 bins) ≤ 15 mm Desert Dust Maritime Smoke

  3. AERONET Inversion 2 • Flexibility and refinements of the algorithm: - any number of spectral channel (from 0.34 to 1.64 mm) - any measurements geometry (almucantar, principle plane, etc.) - dynamic error estimates for all retrieval products - improved assumptions about surface reflectance (Moody et al. 2005) - utilizing measurements of polarization (not operational yet) • New products from retrievals: - particle non-sphericity - direct aerosol radiative forcing computations - degree of polarization, phase function, etc. • New concepts in the retrieval: - non-spherical aerosols - using co-incident satellite observations in the retrievals

  4. AERONET model of aerosol AERONET model of aerosol spherical: Randomly oriented spheroids : (Mishchenko et al., 1997)

  5. Single Scattering using spheroids spheroidkernels data basefor operational modeling !!! Input:wp(Np =11), V(ri) (Ni =22 -26) K- pre-computed kernel matrices: Input: n and k • Basic Model by Mishchenko et al. 1997: • randomly oriented homogeneous spheroids • w(e) - size independent shape distribution Time: < one sec. Accuracy: < 1-3 % Range of applicability: 0.15 ≤ 2pr/l ≤ 280 (26 bins) 0.4 ≤ e ≤ 2.4 (11 bins) 1.33 ≤ n ≤ 1.6 0.0005 ≤ k ≤ 0.5 Output:t(l), w0(l), F11(Q), F12(Q),F22(Q), F33(Q),F34(Q),F44(Q)

  6. NEW CONCEPT - retrieving degree of non-sphericity as an additional parameter The retrieval is possible for aerosols with pronounced coarse fraction, i. e. desert dust and maritime (a < ~ 1.2) Retrieved aspect ratio Non- spheres spheres

  7. AERONET-MSP(multispectral polarization) • Spectral Percent linear Polarization hourly • Standard Products • L(nm): 340, 380, 440, 500, 675, 870, 940, 1020, 1640 • AERONET testing (Feb. to May 2006) • Operational products: June 2006 Dual filter wheel, top for polarizers bottom for IAD filters B.N. Holben

  8. Coarse aerosol Sensitivity of polarization to particle shape -P12(Q)/P11 (Q) -P12(Q)/P11 (Q)

  9. e(spheroids)~ 5%;e(spheres)~ 10% e(spheroids) < 0.01;e(spheres)~ 0.05

  10. Simultaneous Inversion of intensity and Polarization measured in principle plane at 5 channels (0.44; 0.5; 067; 0.87; 1.02) Maarco, August 8, 2004

  11. Combining of observations: satellite, ground-based and aircraft CALIPSO CALIPSO Retrieved: • AEROSOL: • Size Distribution • - Real Refractive Index • Absorption • Vertical variability concentration size altitude concentration • SURFACE : • Albedo • - Bi-directional reflectance LIDAR LIDAR

  12. August 9, 2003 t(0.44) ~ 0.3 Simultaneous fitting AERONET MISR-MODIS MODIS

  13. Comparisons of Surface Retrievals (with improved vertical profile) Surface Albedo: Surface BRDF:

  14. Surface Effect on Retrievals of the fine mode aerosols (low aerosol loading) POLDER: June 24, 2003 t(0.44) ~ 0.26 , SZA=470

  15. Version 2 operational retrieval • More robust, more accurate and better characterized results • Utilize new types of measurements (polarization, principle plane, etc) • Provide new retrieval products: particle shape, forcing, etc. Plans: • Using co-incident observations of MODIS, MISR and POLDER • Including Lidar information into retrievals

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