H. Chepfer, IPSL/LMD, France P. Minnis & L. Nguyen, NASA/LaRC, USA

1. Dual-satellite Retrievals of Tropical Ice Cloud Particle Shapes During CRYSTAL-FACE: Comparisons With In-situ Observations H. Chepfer, IPSL/LMD, France P. Minnis & L. Nguyen, NASA/LaRC, USA D. Baumgardner & G. Raga, UNAM, Mexico

2. Background & Objectives • Unique features of ice crystal scattering phase functions can be exploited to identify the crystal shape by measuring reflectances at different pairs of angles - dual satellite near backscatter (Chepfer et al., JGR, 2002) no validation available! • CRYSTAL-FACE provides opportunity to validate the dual satellite technique and sample another portion of phase function - in situ data, many satellites CAS on WB57 measures 2 angles at forward /backward scatter

3. Selection of scattering phase function using dual-satellites observations: NOAA-16 & GOES-8 • Selection of scattering phase function using in-situ CASdata /WB57 • Comparisons for 2 collocated cloud cases: 9 & 11 July • Link between phase functions and thermodynamical variables for 9 & 11 July • Results for other CRYSTAL-FACE days

4. Scattering Phase Functions l=650 nm CAS SAT1 SAT2 CAS

5. - collocation <15 mn - intercalibration Observations : NOAA-16 & GOES-8 Same cloud area under 2 different directions Selection of scattering phase function using dual satellites observations : GOES-8/NOAA-16 Simulations : Scattering phase functions Doubling-adding RT code Simulate LN16 and LG8 in the two directions : (qs1,qv1,fv1), (qs2,qv2, fv2) Rsat-obs= LN16 /LG8 Rsat-sim= LN16 /LG8

6. 09 July : Result from dual-satellites N16/GOES8 GOES8 Columns, Plates (.05), Spheres

7. 11 July : Result from dual-satellites If sT < 3K : Bul-rosettes , Plates

8. Selection of scattering phase function using in-situ CAS data /WB57:Ris = Ifwd(4-12°) / Ibwd(168-176°) Ris Size Ris Size

9. 09 July : Result from CAS/WB57 Vertical lines correspond to models; histogram for data Columns, compacts, C-Big

10. 11 of July : Result from CAS/WB57 Bullet-rosettes

11. Comparisons of PFs obtained from in-situ and dual-satellites

12. Correlations between PFs and thermodynamical variables for 09 and 11 July cloudy areas (1) T 11 July (bul-rosettes) > T 09 July (columns) => 10K

13. Correlations between PFs and thermodynamical variables for 09 and 11 July cloudy areas (2) Dir V 11J (bul-rosettes): 60° East Dir V 09 J (columns): 260° West Rhi 11July (bul-rosettes) :105% < Rhi 09 July (columns): 125 %

14. Main PF obtained for each day of Crystal-face with CAS/WB57

15. Correlations between PF and thermodynamical variables for all the flights of CRYSTAL-FACE -Selection of cloud /no cloud areas using satellite GOES retrieval of IWP along the WB57 legs -For cloud areas, study of link between Ris and Tis, Teff(GOES), Rhi, V, Dir V. Evidence of correlation between Ris and Dir V:

16. Conclusion & future work • Selection of Phase functions: Satellite & in-situ methods based on ‘bi-directional’ observations in different angles • For 09 and 11 July: Satellite & in-situ give some consistent phase functions Differences between T, Rhi and Dir V for the 2 days • For all CRYSTAL-FACE days: The 2 modes observed July 9 and 11 seem to be representative of complete CRYSTAL-FACE data-set Link between PF and Dir V. No evidence of link with other variables • For all CRYSTAL-FACE days … to be done : • Check collocation between GOES-8 retrieval and WB57 • Use vertical wind to classify the situation … (collocation) … • Improve the IWP satellite retrieval