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4STAR - Introduction

Trace gas and AOD retrievals from a newly deployed hyper-spectral airborne sun/sky photometer (4STAR). M. Segal- Rosenheimer , C.J. Flynn, J. Redemann, B. Schmid, Y. Shinozuka ,S . Dunagan, R.R. Johnson, J.M. Livingston, P.B . Russell. 4STAR - Introduction.

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4STAR - Introduction

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  1. Trace gas and AOD retrievals from a newly deployed hyper-spectralairborne sun/sky photometer (4STAR) M. Segal-Rosenheimer, C.J. Flynn, J. Redemann, B. Schmid, Y. Shinozuka ,S. Dunagan, R.R. Johnson, J.M. Livingston, P.B. Russell

  2. 4STAR - Introduction • 4STAR (Spectrometers for Sky-Scanning, Sun-Tracking Atmospheric Research) is a collaborative development by NASA Ames, PNNL, and NASA Goddard • Instrument Features • AATS-like sun tracking • Aerosol Optical Depth (AOD) at 13 wavelengths • H2O vapor column • Airborne - Horizontally and vertically resolved • AERONET-like direct beam+ sky scanning • AOD • Size distributions (mode-resolved) • Single-scattering albedo (SSA) • Asymmetry parameter • Sphericity • Hyperspectrally resolved (>1,000 channels) • Two spectrometers (UV-Vis-NIR and SWIR) 4STAR Head on DOE G-1 Figure: Internal scheme of the instrument. Fiber optic & electrical cable to spectrometers & controls in cabin

  3. 4STAR – Data Products • Direct Sun Mode– AOD/Trace gases • Direct Sun Mode – Cirrus Optical Depth/Deff (Segal-Rosenheimer et al., in preparation) • Sky Radiance Mode – Size Distributions, SSA (Kassianov et al. submitted) • Zenith Mode – Cloud Optical Depth (w upwelling flux)

  4. 4STAR – Data Products • Direct Sun Mode– AOD/Trace gases • Direct Sun Mode – Cirrus Optical Depth/Deff (Segal-Rosenheimer et al., in preparation) • Sky Radiance Mode – Size Distributions, SSA (Kassianov et al. submitted) • Zenith Mode – Cloud Optical Depth (w upwelling flux)

  5. Analysis Methods Airborne Langley Calibration Langley Flight: July 22nd - Off-coast Cape-Cod

  6. Gas Retrievals Water Vapor (H2O) Instrument Calibrated TOA spectrum (SCHMID ET AL. 1996)

  7. Gas Retrievals NO2/O3 Swap-in new spectrometer just before the campaign – still not well characterized!

  8. Results TCAP (Two Column Aerosol Project Campaign) Hyannis Airport AMF Ground Site Two column location • Airborne (DOE G-1, NASA LaRC King Air) • Surface (DOE AMF-1, MAOS) • July 7-29, 2012 • Cape Cod, MA

  9. Water Vapor (H2O) Flight: July 21st - Off-coast Cape-Cod Relative SD = 2%

  10. Sample spectra (July 21st 2012) Residual Weak water vapor lines Better characterization of spectrometer FWHM is still needed (not constant).

  11. July 21st G-1 Flight path [UT Time] Ocean spirals AMF Ground Site Hyannis Airport

  12. G-1 track and OMI overpass (July 21st) Ozone levels RMS difference = 33 [DU] OMI Overpass : 16:20 UT

  13. G-1 track and OMI overpass (July 22nd) NO2 levels OMI Overpass : 17:03 UT RMS difference= 4x1015 [molec cm-2] = 0.15 DU

  14. Summary: O3/NO2

  15. Sample AOD values (July 15th and 21st) Scattered clouds

  16. Summary and Future Work • 4STAR showed full operational capability in its first science campaign: • Sun tracking • Both spectrometers (UV-Vis-NIR + SWIR) collecting data • Sky Scanning • Zenith viewing • Preliminary science products: • H2O, O3, NO2 • AOD • Gas retrievals should and can be improved by: • Better instrument slit function characterization • Combination of lamp and Langley calibration • Additional validation and comparison work is planned: • DOAS group (Ground ARM site) – NO2 profiles • Better characterization of ozone profile, H2O from radiosonds

  17. THANK YOU! • Major funding from: • NASA Radiation Science Program • Battelle PNW Division • Department of Energy and ARM • NASA Post-Doctoral Program • Weizmann Institute of Science

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