4STAR: Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research

Results from Test-flight Series

PNNLNASA AmesNASA GSFCB. SchmidS. DunaganS. SinyukC. FlynnR. JohnsonE. KassianovP. RussellC. KluzekJ. RedemannM. Segal-RosenheimerY. ShinozukaM. KacenelenbogenJ. LivingstonA collaboration involving:12/2/201114STAR: Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research AERONET-like capabilityGround-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 H2Ohorizontally and vertically resolved

12/2/20112Meet the family

4STAR(2012-

AATS-6(1985-2001)AATS-14(1996-12/2/20113

4STAR Integration on PNNL/Battelle G-1

12/2/20114Anticipated 4STAR data products:Solar Direct BeamAtmospheric TransmittanceAerosol Optical Depth and ngstrom exponentAerosol Extinction (via aircraft vertical profiling)Gases: H2O, O3, NO2, CO2 (column and in profile) Angularly-resolved sky radiance inversionsScattering phase function, asymmetry parameterAerosol size distributions, fine/coarse mode fractionAerosol sphericityAerosol absorptionZenith 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.)

12/2/20115Ground Prototype Heads (4STAR-G)

12/2/20116

4STAR-GroundAERONET CimelJens RedemannRoy Johnson12/2/20117

12/2/20118Sun Photometer Inter-Comparison Experiment Mauna Loa, Aug. 24 - Sep. 2 2008

4STARPredeAATS-143 AERONET Cimels12/2/20119Mauna Loa (August 2008) AOD Intercomparison

12/2/201110Mauna Loa (August 2008) Water Vapor Intercomparison

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3 flights in Sep 2010:

Pilots only: Airworthiness certificationScience ops: Pasco, WA to San Jose, CAScience ops: San Jose local

2 flights in April 2011: Pasco - Eastern WA, Idahomax alt 5.7 km

Vertical profile of optical depth(normalized to top of layer)

13 l (nm)9/28/2010SJC ~10 amFinal flight series (late Aug 2011)14 max alt 5.7 km

TestCapabilityFORJCTestingLangleyCalibrationScienceExampleAirborne Langley Plot (Aug 30, 2011)15

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AODs during Airborne Langley Plot (Aug 30, 2011)

Stray light rejection close to Sun

12/2/201118Sensitivity of retrievals to stray light close to sun (3-6)

15%20%

Sensitivity of retrievals to stray light close to sun (3-6)Poster A11H-0196, Kassianov et al.Next stepsFY12: bring 4STAR to full science capabilityImprove FOV uniformity of sun opticsImprove scattering isolation of sky opticsApply correction of stray light inside spectrometerHardening and retrieval algorithmsDOE/ARM Mission on G-1, Cape Cod, July 2012 & Feb 2013Possible Mission on NASA DC-8,(SEAC4RS, Asia), Aug-Sep 2012Funding: NASA, DOE ARM, BMI, PNNL12/2/201121