Landsat cal/val using airborne sensors

Joel McCorkel1, Frank Padula2, Boryana Efremova1,2, Matt Montanaro1,3

1NASA’s Goddard Space Flight Center 2NOAA/GeoThinkTank

3Rochester Institute of Technology

Landsat Science Team Meeting

USGS EROS Center, Sioux Falls, SD

12 July 2017

Overview

• GOES-R post-launch airborne science Cal/Val field campaign introduction

• Landsat coordination with the GOES-R flight campaign

• Landsat 8 TIRS comparison with S-HIS (airborne thermal hyperspectral)

• Moving forward with airborne measurements for Landsat

Satellite Program Validation Field Campaigns

» Committee on Earth Observation Satellites (CEOS) and GSICS recognized best practice:

http://qa4eo.org/docs/QA4EO-WGCV-IVO-CLP-004_vDraft.pdf

• Field campaigns are essential for collecting reference data that can be directly related to satellite observations

• Reference data:

o Collected in ideal validation conditions using well calibrated reference sensors

o Used to validate and characterize post-launch instrument performance

• Field campaigns are implemented on all major satellite programs to ensure post-launch validation of system performance (Ex: MODIS, ASTER, AIRS, S-NPP/CrIS & VIIRS, Landsat, SeaWIFS, OCO-2, GPM, TRMM)

• Often field campaigns are funded separately at the L1b and individually for select L2+ products

• The GOES-R field campaign provided a coordinated programmatic approach that consolidates these efforts in support of L1b & L2+ products

Independent Validation of Predicted Performance:

ABI radiometric accuracy (5 % or 1 K uncertainty) GLM flash detection efficiency (70 %) & false alarm rate (5 %)

3 Padula et al 2017

GOES-R Field Campaign Overview

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Goal of the GOES-R field campaign was to support post-launch validation of Advanced Baseline Imager (ABI) &

Geostationary Lightning Mapper (GLM) L1b & L2+ products:

− ~9 weeks (~100 flight hours)

− March 21 – May 17, 2017

− High-altitude NASA ER-2 platform coordinated with ground based reference data over several Earth targets

− Underflights to be collected, when possible, with low Earth orbit environmental satellites which may include S-NPP, Terra/Aqua, METOP, Landsat, ISS & GPM

− Open access data policy, web portal

− NCEI long-term archive

NASA ER-2

ER-2 high-altitude aircraft preparing for GOES-16 validation flights

GOES-R Field Campaign ER-2 Based Instruments

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AVIRIS-NG

LIP

CPL

LIP

GOES-R Field Campaign ER-2 Based Instruments

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CRS

FEGS

GCAS

LIP

EXRAD

S-HIS

INMARSAT

Airborne instrument for thermal channel validation: Scanning High-Resolution Interferometer Sounder (S-HIS) University of Wisconsin (Hank Revercomb and Joe Taylor)

• Scanning-HIS: Michelson plane mirror interferometer, 100mrad FOV corresponding to 2km (nadir) at 20km altitude. The instrument uses HeNe metrology laser for fringe counting, and carries two blackbodies (BB) for radiometric calibration. The interferograms have spectral resolution of about 0.5 cm-1 (see Tobin et al. 2006).

• Accurate radiometric calibration is achieved by frequent viewing of the onboard blackbody calibration references (Rivercomb et al. 1988). ABB (ambient BB) is unheated, HBB (heated BB) is at about 310K. BB built with NIST traceable calibration 3 sigma absolute uncertainties within 0.10 K (Best et al., 1997, 2003). Calibration is verified before and after field campaigns at UW. Comparisons of the S-HIS against NIST TXR have shown agreement to within 0.03 K (Rivercomb et al. presentation at TC4 Science Team Meeting 2017).

• The error analysis for this study is in progress. Previous studies (Tobin et al., 2006) report overall S-HIS LWIR 3 sigma uncertainty below 0.2K for scene temperatures higher than ~240K.

GOES-R Post Launch Airborne Science Cal/Val Field Campaign (March 21 to May 17, 2017)

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*Flight #10 - April 27, 2017 - Huntsville, AL not shown due to aircraft navigation reporting issue

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The GOES-R field campaign provided a coordinated programmatic approach to independently validate post-launch performance of ABI & GLM L1b & L2+ products

ER-2 flight highlight from May 7, 2017

1606Z Landsat 8

Non-operational imagery, still undergoing post launch testing Targeted Inter-Comparison:

GOES-R Airborne Reference Spectrometers & Landsat 8

S-HIS and TIRS Landsat 8 Overlap

• The S-HIS observations are overlaid over the two Landsat 8 images taken during the ER2 underpass (top plots).

• Only the nadir S-HIS data is used in the comparison (pink).

• Spatially, TIRS pixels within 33pix radius are averaged to match the S-HIS (2km diameter) FOV.

• The TIRS scene uniformity over the S-HIS FOV is shown as error bars (1 sigma) on the radiance (bottom) plot.

Landsat coordination with GOES-R campaign

-14 minutes

+10 minutes

TIRS Stray-Light Correction Effect

• A correction for stray-light was introduced to the Landsat 8 TIRS calibration in

February 2017 (Gerace and Montanaro, 2017). • The radiance ratio of scene 018039 calibrated without stray light correction to the

corrected scene (current L1T product) is shown below.

Reference: Aaron Gerace, Matthew Montanaro, Derivation and validation of the stray light correction algorithm for the thermal infrared sensor onboard Landsat 8, Remote Sensing of Environment, Volume 191, 15 March 2017, Pages 246-257, ISSN 0034-4257, http://dx.doi.org/10.1016/j.rse.2017.01.029.

S-HIS and TIRS TOA Radiance and Temperature Comparison B10

Data used to derive bias

• Bias over uniform ocean scenes within 5-minute time difference is within 0.1K for both B10 and B11.

• The B10 bias is 0.07 ∓ 0.05K (pink) compared to -0.3 K (blue) before the stray light correction.

S-HIS and TIRS TOA Radiance and Temperature Comparison B11 • Bias over uniform ocean scenes within 5-minute time difference is within 0.1K

for both B10 and B11.

• The B11 bias is 0.04 ∓ 0.07K compared to 0.4 K before the stray light correction.

Data used to derive bias

Moving forward

• Short term • Landsat 8 OLI-AVIRIS inter-comparison • GOES-16 ABI inter-calibration with Landsat sensors • Use S-HIS and AVIRIS as transfer radiometer between all sensors under-

flown during GOES-R flight campaign including MODIS, VIIRS, Landsat 8, and ABI

• Longer term • Potential Landsat 9 post-launch airborne science Cal/Val flight campaign

• validation of OLI-2 & TIRS-2 L1b spectral radiance observations to validate SI traceability

• provide validation of Landsat 8 and Landsat 7 and other land imaging satellite instruments to ensure interoperability between systems

• provide observations surface and atmospheric geo-physical measurements to support advanced product development

• Airborne instrument investigations for Landsat future capabilities and measurements

Backup

Landsat 9 TIRS-2 scattered light performance

• Optical modeling used to assess performance of optical design changes from TIRS-1 to TIRS-2

• Two independent modeling groups • NASA Goddard • Space Dynamics Laboratory

• Two phases of model development

• 2/2016 – 5/2016: TIRS-2 scattered light performance, results presented at EPR & PDR

• 8/2016 – 2/2017: Scatter light measurement modeling, results presented at EPR and CDR

March 23, 2017 – Sonoran Desert Mission

ABI reflective solar band primary validation flight

ER-2 Flight Track

March 23, 2017 –Two sets of ER-2 consecutive circle patterns (20 circles total) conducted to match the AVIRISng high-altitude aircraft based sensor view geometry with ABI over the Sonoran Desert

S-HIS / Landsat 8 TIRS comparison

S-HIS – spectrum from 3.6 to 17.2 μm is shown in grey (sampling of 0.48 cm-1 or about 0.0056 μm at 10.8 μm and 0.007 μm at 12 μm). Overlayed in green and orange are the Ladsat 8 TIRS: B10 – 10.8 μm, and B11 – 12 μm respectively.

The Landsat 8 TIRS and S-HIS observations are nearly simultaneous over the Gulf of Mexico near the coastline and have up to 14min and 10 min time differences at the north and south ends of the overlapping track respectively.

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Primary Validation Approach (Direct Comparison) NSS Collections + High-Altitude Aircraft Sensors: provides an absolute validation capability of ALL ABI detectors and is the primary pathway to validate SI traceability

Secondary Validation Approach (Earth as Reference) Near Surface UAS Collection (Development): towards an absolute validation capability (long-term), a secondary pathway to validate SI traceability (RSB surface channels), and product performance uncertainties

Secondary Validation Approach (Direct Comparison) NSS + SNO Collection: a secondary pathway to validate SI traceability of ALL ABI detectors through reference instrument(s)

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GLM

GOES-R Field Campaign: ABI Primary Validation Approach

Satellite

Achieving this objective validates the ABI radiometric predicted performance of 5 %

or 1 K uncertainty

Near Surface UAS

ABI SNO Special Collection

High-Altitude Aircraft

ABI