Reflected Solar Calibration Demonstration System Update

1. National Aeronautics and Space Administration Goddard Space Flight Center Reflected Solar Calibration Demonstration System Update J. McCorkel K. Thome D. Jennings B. McAndrew J. Hair D. Rabin A. Daw

2. Calibration Demonstration System • SOlar, Lunar for Absolute Reflectance Imaging Spectrometer (SOLARIS) • Technology demonstration of • Design and production of optics • Depolarizer technology • Test prelaunch calibration methods • Evaluate reflectance retrieval • Demonstrate transfer-to-orbit error budget showing SI-traceability CLARREO SDT Meeting

3. Status at last SDT (Oct 2012) • Finalized ‘Blue’ box with improved grating, cooled and stabilized detector, and order-sorting filter • Signal linearization developed for detector package • Silicon trap radiometers obtained for SIRCUS facility at GSFC • Improved laser stability allowed for SOLARIS calibration from 560-979 nm scan at 1-nm steps • Goddard IRAD funds provided to calibrate an airborne imaging spectroradiometer using SOLARIS facilities • 3% absolute uncertainty in NIR portion of spectrum CLARREO SDT Meeting

4. CDS build status • Improved blue box • Optics and assembly finished • Cooled silicon detector • Awaiting final data acquisition software development • Red box • Optics and assembly finished • MCT detector installed • “Suitcase” SOLARIS • Highly portable version of SOLARIS • COTS high resolution detector package • Completed assembly and initial calibration • Recently deployed for field collections CLARREO SDT Meeting

5. Calibration • SOLARIS is used to demonstrate CLARREO calibration approaches • Laser-based, “monochromatic” source is basis for CLARREO laboratory calibration CLARREO SDT Meeting

6. SIRCUS instrumentation Fancy light bulb: SIRCUS Spectral irradiance and radiance responsivity calibrations using uniform sources (SIRCUS) • Key to SIRCUS is use of highly-accurate monitoring radiometers • 4 Silicon trap detectors have been calibrated at NIST • 5 InGaAsdetectors and 5 sphere (Si, IGA, extended IGA detectors) undergoing stability monitoring 550-800 nm Parametric oscillator Ti:Sapphire 700-1000 nm 1100-1600 nm 1750-3300 nm Idler Transfer radiometers 350-500 nm 240-330 nm CLARREO SDT Meeting

7. SIRCUS setup CLARREO SDT Meeting

8. G-LiHT • Goddard's LidarHyperspectral and Thermal airborne imager (www.gliht.gsfc.nasa.gov) • Scanning LiDAR • Broadband thermal camera • DownwellingVNIR irradiance spectrometer • Upwelling VNIR imaging spectrometer • Calibrating G-LiHT’s imaging spectrometer with the SOLARIS/CLARREO facility gives further experience with the SIRCUS set up • Allowed development of calibration approaches coincident with SOLARIS hardware work • Evaluate sensor effects on calibration • Develop techniques to evaluate sphere source uniformity • Transfer of calibration to operational conditions CLARREO SDT Meeting

9. Recent G-LiHT measurements Recent G-LiHT measurements • SIRCUS 417-~450 nm, 550-~1015nm in 1-nm interval • This is our largest and most complete SIRCUS dataset yet • All G-LiHT measurements were coincident with Silicon trap radiometer and ASD Handheld2 measurements • Transfer characterization of nadir pixels to off-nadir w/ white light sphere measurements • G-LiHThas an extremely large field-of-view of 50° • ‘Nadir’ G-LiHT spatial pixels correspond to signal of silicon trap radiometer • Off-nadir pixels view area of sphere that is not monitored • Rotate G-LiHT to calibrate all detectors viewing the monitored portion of the sphere • Impact of rotation on sphere output • Temporal stability of sphere CLARREO SDT Meeting

10. Sphere study with G-LiHT With and without baffle-aperture G-LiHT needed to be mounted such that its spatial direction could scan a point on the back wall of the integrating sphere. G-LiHT rotated in 2° increments so that each part of the focal plane sampled a similar area in the sphere. The baffle/aperture with 4x4’’ port limits the impact of the sensor under test on sphere output CLARREO SDT Meeting

11. SuitcaseSOLARIS mobile setup Highpassfilter allows us to study a single order with the COTS detector without higher cost of an on-detector order sorting filter Larger size and lateral offset of COTS focal plane captures Zero order of diffraction grating for further study of stray light Initial outdoor testing of SuitcaseSOLARISfield-portable system enabled by a compact COTS detector. CLARREO SDT Meeting

12. G-LiHT and SOLARIS • The G-LiHT and SuitcaseSOLARISwork allowed for a unique opportunity after the launch of LDCM (Landsat 8) • Use the SIRCUS-based calibrated sensors as part of planned cal/val activities for LDCM OLI • Evaluate intercalibration approaches • Activities centered around March 29-31 • LDCM was being inserted into its final orbit • Passed “under” Landsat 7 allowing cross-comparisons between sensors on two platforms • SOLARIS team collected data at two test sites in desert southwest CLARREO SDT Meeting

13. Test site and team photos Joel and Don (693) Kurt and Jason Joel (618), Jason (505), Jeff (U. Arizona), Kurt (618) CLARREO SDT Meeting

14. NASA Earth Observatory Image of the Day 4/16/2013 http://earthobservatory.nasa.gov/IOTD/view.php?id=80913 G-LiHT (B. Cook) SOLARIS

15. March 31, 2013 Measurement summary CLARREO SDT Meeting

16. CDS integration, test, and cal flow Current status FY 2014 CLARREO SDT Meeting

17. Summary • Work in FY2013 concentrated on taking SOLARIS to the 1% plateau • Transfer radiometer calibration at NIST • Refining laboratory calibration methods • Finalizing SOLARIS hardware • Remaining work in FY2013 will • Demonstrate error budget for reflectance retrieval • Subject error budget to NIST review • Produce a peer-reviewed SI-traceability for CLARREO-like measurements • Evaluation of absolute solar irradiance calibration • Lunar model verification from ground-based collects CLARREO SDT Meeting

18. Summary • SOLARIS CDS will play key role demonstrating CLARREO-quality error budgets • Collaborative efforts with NIST will continue to be critical • ‘Operational’ use of SIRCUS • Extension to wavelengths > 1 micrometer • Broadband calibration approaches (HIP) • Calibration approaches will be demonstrated • Laboratory calibration protocols • Error budget demonstration • Reflectance retrieval • Stray light characterization • Instrument model assessment CLARREO SDT Meeting