1 GSFC CDS Activities and Plans for 2016 K. Thome, A. Angal, J. McCorkel NASA/GSFC CLARREO SDT Meeting Hampton, VA December 1-3, 2015

2 CLARREO RS GSFC Overview Past eight months since last meeting has seen work on both Calibration Demonstration System (CDS) as well as Pathfinder Coordinating and collaborated with other projects to optimize resources NIST involvement Sharing resources with VIIRS Characterization of airborne polarimeter (RSP) Improvements to laboratory calibration system Automation and robustness Extension to SWIR Analysis of field data

3 Key outcomes for past eight months Achieved output at SWIR wavelengths Compared results from silicon trap and InGaAs transfer radiometers Demonstrated relevance of CLARREO calibration approaches to multiple missions NIST and JPSS project review (and approval) of CLARREO laboratory protocols and hardware RS-CDS laboratory techniques became part of the Landsat 9 OLI characterization plan Created a close collaboration with PACE team Demonstrated applicability of CDS calibration approaches to CLARREO through airborne systems

4 Reminder - RS Instrument Benchmark reflectance from ratio of earth view to measurements of irradiance while viewing the sun Offner system covering 320 to 2300 nm with 500-m GIFOV and 100-km swath width Reflectance traceable to SI standards at an absolute uncertainty <0.3% Lunar data provide calibration verification Inetrcalibration plays a key role in developing climate record

5 RS calibration approach Ensure prelaunch calibration simulates on-orbit sources Transfer to orbit through accurate prediction of sensor behavior while viewing known sources Characterize sensor to SI-traceable, absolute radiometric quantities during prelaunch calibration Component and system level data used to develop hi fidelity sensor model

6 SOLARIS CDS testing overview Laboratory Calibration High-accuracy, SI-traceable, detector- based, absolute radiometric Sensor Model Developed from component and system level data Follow calibration plan for CLARREO with emphasis on radiometric and spectral calibrations, sensor stray light, and optical modeling Field collections To understand on- orbit approaches

7 RS CDS Laboratory work More small steps leading to significant progress Calibrations of several imagers Updated calibration hardware to improve automation and repeatability Gap-filling and expanding spectral output Greatly shortened time (8x reduction) to accomplish calibration in the laboratory

8 SIRCUS and GLAMR Collaboration with NIST’s SIRCUS continued Recall SIRCUS is a laser-based, monochromatic calibration approach GLAMR (GSFC Laser for Absolute Measurement of Response) is CLARREO’s version of SIRCUS Work with other projects has helped the NIST/CLARREO collaboration Becoming a true collaboration Increasing NIST’s reviews of GLAMR

9 GLAMR: Detector-based calibration G-LiHT view of the integrating sphere illuminated at 679 nm

10 VNIR set up for GLAMR M1 M2 LBO SHG Stabilizer Shutter Prisms M4 M3 M5 M6

11 Now for SWIR M4 M3 M7 SHG M1 M2 LBO M5 M6 M8

12 SWIR first light on Oct. 9, 2015 Tuning through wavelengths up to 1575 nm Response of the NIST-traceable transfer radiometer (InGaAs detector) was also recorded Wavelength range between 940 – 1000 nm was scanned for comparison between Si-trap and InGaAs Differences are larger than acceptable Detector responses are not optimal for these wavelength ranges InGaAs Si-Trap

13 OPO Laser Alignment Framework (OLAF) Large diameter wheels Fork slots Paladin interface plate Bottom shelving for diode pump, chiller, etc. Top shelving for control electronics Custom Newport optical breadboard table Improved travel-capable laser table Length is shorter than opening of FedEx Custom Critical truck Enclosure for laser safety is not shown Components (frame, table, enclosure) for OLAF have been delivered

14 Learning lessons from real sensors GISS Research Scanning Polarimeter (RSP) was calibrated with GLAMR in July Provided a test of GLAMR automation Data showed an issue with laser performance Led to changes in laser design and alignment Alignment changes doubled output power Added prism in laser ring cavity to improve spectral stability Factor of five improvement in the laser output power between 410 and 500 nm

15 SOLARIS and field work RS CDS efforts include ground and airborne instruments Goddard airborne imaging spectrometer calibrated in the CLARREO CDS facility SOLARIS on the ground Parking lot measurements All are key to showing that laboratory calibration can translate to real life

16 Field data and instrument modeling One key to CLARREO RS traceability is an instrument model Allows a transfer to orbit of laboratory accuracy RS team and researchers at RIT developed a sensor model of RS-CDS (SOLARIS) in Digital Imaging and Remote Sensing Image Generation (DIRSIG) Started evaluating different imaging scenarios including Algodones Dunes Will support instrument trade studies for design and during-build analysis in addition to quantifying inter-calibration uncertainties

17 Lab-based to reflectance-based calibration GLAM R G-LiHT G-LiHT Red Lake Playa Transfer G-LiHT radiance at 1000m to 705 km (L7/L8) via radiative transfer Integrate 1nm G-LiHT radiance spectrum over Landsat RSR (band 4 and 5) L8 OLI TOA radiance Red Lake Playa L7 ETM+ TOA radiance Red Lake Playa Compare on-orbit calibration (L7 ETM+ and L8 OLI) to lab-based G- LiHT calibration

18 Field Calibration Results 18 Red Lake Playa 29 March 2013 McClaw Playa 31 March 2013 Results between lab-based calibration and reflectance based vicarious calibration agree within ±5% Reflectance-based results are a limiting factor

19 SuitcaseSOLARIS was included in the VIIRS testing with a Flat- Plate Illuminator NIST developed the FPI to provide a thermal vacuum-compatible radiance source Used for VIIRS as a trending source SuitcaseSOLARIS measured the FPI at three output levels with three integration time configurations NIST will supply the CLARREO team with FPI output values Compare NIST-supplied radiance with SuitcaseSOLARIS results

20 SOLARIS and VIIRS One important element to CDS work is demonstrating impacts on other programs SOLARIS/CLARREO team took part in a review of the Goddard Laser for Absolute Measurement of Radiance (GLAMR) in October Primary audience was the JPSS project to evaluate use of GLAMR for the testing of J2 VIIRS in Spring 2016 Review included representatives from NIST and Landsat 9 Positive response from reviewers on GLAMR’s current state, its accuracy and traceability, and feasibility for use with J2 VIIRS testing

21 FY16 Plan Document laboratory calibration uncertainty below 1% (k=2) to 1.6 micrometers Demonstrate transfer of NIST calibration accuracies in CLARREO RS facility to 1.6 micrometers Implement improved laser source Round-robin with NIST using portable RS CDS Recurring peer reviews of the CLARREO calibration approach at NIST Collaborate with NIST on J2 VIIRS calibration Refined calibrations of RS CDS, portable RS CDS, and G-LiHT Implementation of NIST-calibrated reflectance standard to evaluate uncertainties RS Instrument model development

22 FY17 Plan Document laboratory calibration uncertainty below 1% (k=2) to 2.3 micrometers Absolute reflectance retrieval comparison to NIST standards to evaluate uncertainties RS Instrument model development Further measurements of solar and lunar irradiance in addition to field deployments Repeatability of lunar retrievals Absolute measurement of solar irradiance NIST-calibrated transfer radiometer data acquisition system completed to 2.3 micrometers Implementation of extended InGaAs transfer radiometers

23 Where we are and where we want to be Have the equipment and methods needed to achieve <1% radiometric uncertainty (k=2) Produce a NIST-reviewed, SI-traceable error budget for CLARREO-like measurements Evaluate solar irradiance calibration and lunar model verification from ground-based collects High fidelity instrument model to allow transfer of laboratory characterization to orbit SOLARIS will show detector-based methods can be used to characterize imaging spectrometers Stray light Absolute radiometric calibration Where do we really want to be? – Testing the on- orbit version of CLARREO

24 CLARREO Pathfinder is a great opportunity for RS Step towards demonstrating measurement technologies for full mission Difficult decisions remain on how to meet schedule and cost Lessons learned from implementing Pathfinder will be invaluable to CLARREO as well as other earth science missions Laboratory calibration approaches On-orbit operations and improved calibration Challenges of high-accuracy intercalibration Prove first on-orbit SI traceable calibration methodologies to achieve accuracies 10x higher than current RS instruments Identify possible design modifications for full mission ISS orbit enhances sampling for inter-calibration of existing sensors Put moon on an SI-traceable scale with 10x accuracy improvement