1. 4STAR: Spectrometer for Sky-Scanning, Sun- Tracking Atmospheric Research Results from Test-flight Series PNNLNASA AmesNASA GSFC B. SchmidS. DunaganS. Sinyuk C. FlynnR. Johnson E. KassianovP. Russell C. KluzekJ. Redemann M. Segal-Rosenheimer Y. Shinozuka M. Kacenelenbogen J. Livingston A collaboration involving:

2. 4STAR: Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research AERONET-like capability Ground-based direct beam + sky scanning yields column- integrated properties: AOD Size distributions Single-scattering albedo Asymmetry parameter Sphericity Cloud OD 4STAR: AATS-like capability: AOD at 13 wavelengths H 2 O horizontally and vertically resolved AATS-like capability: AOD at 13 wavelengths H 2 O horizontally and vertically resolved

3. Meet the family…4STAR(2012- AATS-6(1985-2001) AATS-14(1996-

4. 4STAR Integration on PNNL/Battelle G-1

5. Anticipated 4STAR data products: Solar Direct Beam Atmospheric Transmittance Aerosol Optical Depth and Ångstrom exponent Aerosol Extinction (via aircraft vertical profiling) Gases: H 2 O, O 3, NO 2, CO 2 (column and in profile) Angularly-resolved sky radiance inversions Scattering phase function, asymmetry parameter Aerosol size distributions, fine/coarse mode fraction Aerosol sphericity Aerosol absorption Zenith radiance cloud retrievals Cloudy/clear transition zone (Marshak, Chiu) Cloud Optical Depth, Droplet effective Radius (with auxilliary measurements, Barker et al.) Water vapor, liquid water, ice water fractionation (Daniels et al.)

6. Ground Prototype Heads (4STAR-G)

7. 4STAR-Ground AERONET Cimel Jens Redemann Roy Johnson

9. Sun Photometer Inter-Comparison Experiment Mauna Loa, Aug. 24 - Sep. 2 2008 4STAR Prede AATS-14 3 AERONET Cimels

10. Mauna Loa (August 2008) AOD Intercomparison

11. Mauna Loa (August 2008) Water Vapor Intercomparison

12. 12 3 flights in Sep 2010: 1.Pilots only: Airworthiness certification 2.Science ops: Pasco, WA to San Jose, CA 3.Science ops: San Jose local 2 flights in April 2011: Pasco - Eastern WA, Idaho 3 flights in Sep 2010: 1.Pilots only: Airworthiness certification 2.Science ops: Pasco, WA to San Jose, CA 3.Science ops: San Jose local 2 flights in April 2011: Pasco - Eastern WA, Idaho max alt 5.7 km

13. Vertical profile of optical depth (normalized to top of layer) 13 (nm) 9/28/2010 SJC ~10 am

14. Final flight series (late Aug 2011) 14 max alt 5.7 km Test Capability FORJC Testing Langley Calibration Science Example

15. Airborne Langley Plot (Aug 30, 2011) 15

16. 16 AODs during Airborne Langley Plot (Aug 30, 2011)

18. Stray light rejection close to Sun

19. Sensitivity of retrievals to stray light close to sun (3-6°) 15% 20%

20. Sensitivity of retrievals to stray light close to sun (3-6°) Poster A11H-0196, Kassianov et al.

21. Next steps… FY12: bring 4STAR to full science capability Improve FOV uniformity of sun optics Improve scattering isolation of sky optics Apply correction of stray light inside spectrometer Hardening and retrieval algorithms DOE/ARM Mission on G-1, Cape Cod, July 2012 & Feb 2013 Possible Mission on NASA DC-8,(SEAC4RS, Asia), Aug-Sep 2012 Funding: NASA, DOE ARM, BMI, PNNL