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ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023

Md Obaidul Haque, Rajagopalan Rengarajan, Mark Lubke, Md Nahid Hasan, Ashish Shrestha, Fatima Tuz Zafrin Tuli · U.S. Geological Survey

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ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023

Open-File Report 2023–1075

U.S. Department of the Interior U.S. Geological Survey

ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023 By Md Obaidul Haque, Rajagopalan Rengarajan, Mark Lubke, Md Nahid Hasan, Ashish Shrestha, Fatima Tuz Zafrin Tuli, Jerad L. Shaw, Alex Denevan, Shannon Franks, Kathryn Ruslander, Esad Micijevic, Michael J. Choate, Cody Anderson, Kurt Thome, Ed Kaita, Julia Barsi, Raviv Levy, Jeff Miller, and Leibo Ding

Open-File Report 2023–1075

U.S. Department of the Interior U.S. Geological Survey

U.S. Geological Survey, Reston, Virginia: 2023

For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment—visit https://www.usgs.gov or call 1–888–392–8545. For an overview of USGS information products, including maps, imagery, and publications, visit https://store.usgs.gov/ or contact the store at 1–888–275–8747. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. Suggested citation: Haque, M.O., Rengarajan, R., Lubke, M., Hasan, M.N., Shrestha, A., Tuli, F.T.Z., Shaw, J.L., Denevan, A., Franks, S., Ruslander, K., Micijevic, E., Choate, M.J., Anderson, C., Thome, K., Kaita, E., Barsi, J., Levy, R., Miller, J., and Ding, L., 2023, ECCOE Landsat quarterly Calibration and Validation report—Quarter 2, 2023: U.S. Geological Survey Open-File Report 2023–1075, 39 p., https://doi.org/10.3133/ofr20231075. Associated data for this publication: U.S. Geological Survey, 2021, EarthExplorer: U.S. Geological Survey database, https://earthexplorer.usgs.gov. ISSN 2331-1258 (online)

iii

Contents Executive Summary��1 Introduction��1 Background��1 Purpose and Scope��2 Processing Level Definitions��2 Level 0��2 Level 1��2 Level 2��2 Landsat Collection Definitions��2 Landsat Collection 1��3 Landsat Collection 2��3 Landsat 8 Radiometric Performance Summary��3 Operational Land Imager Signal-to-Noise Ratio��3 Thermal Infrared Sensor Noise Performance��10 Radiometric Stability��10 Updates to Absolute Radiometric Calibration��18 Relative Gains��19 Landsat 8 Geometric Performance Summary��23 Band Registration Accuracy��23 Operational Land Imager to Thermal Infrared Sensor Alignment��25 Geometric Accuracy��25 Geodetic Accuracy��28 Landsat 8 to Sentinel-2 Registration Accuracy��28 Landsat 7 Radiometric Performance Summary��29 Onboard Calibrator Trends��29 Coherent Noise��31 Pseudoinvariant Calibration Sites Trending��31 Landsat 7 Geometric Performance Summary��32 Geometric Performance Summary��32 Geodetic Accuracy��32 Band Registration Accuracy��33 Orbital Drift from Worldwide Reference System-2��35 Quarterly Level 2 Validation Results��36 Level 2 Surface Reflectance Pseudoinvariant Calibration Site Trending��36 Summary��38 References Cited��38

Figures 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23.

Graph showing Landsat 8 Operational Land Imager signal-to-noise ratio performance, June 2023��5 Graph showing Landsat 8 Operational Land Imager coastal/aerosol band lifetime signal-to-noise ratio stability��5 Graph showing Landsat 8 Operational Land Imager blue band lifetime signal-to-noise ratio stability��6 Graph showing Landsat 8 Operational Land Imager green band lifetime signal-to-noise ratio stability��6 Graph showing Landsat 8 Operational Land Imager red band lifetime signal-to-noise ratio stability��7 Graph showing Landsat 8 Operational Land Imager near infrared band lifetime signal-to-noise ratio stability��7 Graph showing Landsat 8 Operational Land Imager shortwave infrared 1 band lifetime signal-to-noise ratio stability��8 Graph showing Landsat 8 Operational Land Imager shortwave infrared 2 band lifetime signal-to-noise ratio stability��8 Graph showing Landsat 8 Operational Land Imager cirrus band lifetime signal-to-noise ratio stability��9 Graph showing Landsat 8 Operational Land Imager panchromatic band lifetime signal-to-noise ratio stability��9 Graph showing Landsat 8 Thermal Infrared Sensor band 10 lifetime noise performance��10 Graph showing Landsat 8 Thermal Infrared Sensor band 11 lifetime noise performance��11 Graph showing Landsat 8 Operational Land Imager coastal/aerosol band lifetime radiometric stability��11 Graph showing Landsat 8 Operational Land Imager blue band lifetime radiometric stability��12 Graph showing Landsat 8 Operational Land Imager green band lifetime radiometric stability��12 Graph showing Landsat 8 Operational Land Imager red band lifetime radiometric stability��13 Graph showing Landsat 8 Operational Land Imager near infrared band lifetime radiometric stability��13 Graph showing Landsat 8 Operational Land Imager shortwave infrared 1 band lifetime radiometric stability��14 Graph showing Landsat 8 Operational Land Imager shortwave infrared 2 band lifetime radiometric stability��14 Graph showing Landsat 8 Operational Land Imager panchromatic band lifetime radiometric stability��15 Graph showing Landsat 8 Operational Land Imager cirrus band lifetime radiometric stability��15 Graph showing Landsat 8 Thermal Infrared Sensor band 10 radiometric stability (side A)��16 Graph showing Landsat 8 Thermal Infrared Sensor band 11 radiometric stability (side A)��16

24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42.

43. 44. 45. 46. 47. 48.

Graph showing Landsat 8 Thermal Infrared Sensor band 10 radiometric stability (side B)��17 Graph showing Landsat 8 Thermal Infrared Sensor band 11 radiometric stability (side B)��17 Graph showing Landsat 8 Operational Land Imager lifetime gain trends and calibration gain updates��18 Graph showing Landsat 8 Thermal Infrared Sensor gain degradation since the safehold event on November 1, 2020��19 Graph showing Landsat 8 Operational Land Imager coastal/aerosol band per-detector change in relative gains between quarter 1 and quarter 2, 2023��20 Graph showing Landsat 8 Operational Land Imager shortwave infrared 1 band per-detector change in relative gains between quarter 1 and quarter 2, 2023��20 Graph showing Landsat 8 Operational Land Imager shortwave infrared 2 band per-detector change in relative gains between quarter 1 and quarter 2, 2023��21 Graph showing Landsat 8 Operational Land Imager panchromatic band per-detector change in relative gains between quarter 1 and quarter 2, 2023��21 Graph showing Landsat 8 Operational Land Imager shortwave infrared 1 lifetime jumps in detector responsivity��22 Graph showing Landsat 8 Operational Land Imager shortwave infrared 2 lifetime jumps in detector responsivity��22 Graph showing Operational Land Imager lifetime band registration accuracy by quarter��24 Graph showing Landsat 8 Thermal Infrared Sensor lifetime band registration accuracy by quarter��24 Graph showing Landsat 8 Thermal Infrared Sensor to Operational Land Imager lifetime band registration accuracy by quarter��25 Graph showing Landsat 8 Thermal Infrared Sensor to Operational Land Imager lifetime pitch alignment��26 Graph showing Landsat 8 Thermal Infrared Sensor to Operational Land Imager lifetime roll alignment��26 Graph showing Landsat 8 Thermal Infrared Sensor to Operational Land Imager lifetime yaw alignment��27 Graph showing Landsat 8 lifetime geometric accuracy by quarter��27 Graph showing Landsat 8 lifetime geodetic accuracy by quarter��28 Graph showing Landsat 8 coregistration error between the Level 1 terrain-corrected product and Sentinel-2 Level 1 orthorectified product since quarter 1, 2021��29 Graph showing Landsat 7 Enhanced Thematic Mapper Plus blue band lifetime gains��30 Graph showing Landsat 7 Enhanced Thematic Mapper Plus shortwave infrared 1 band lifetime gains��30 Graph showing Landsat 7 Enhanced Thematic Mapper Plus lifetime coherent noise��31 Graph showing Libya 4 pseudoinvariant calibration site top of atmosphere reflectance trending normalizing/correcting seasonality effects, Collection 2��32 Graph showing Landsat 7 lifetime mean offsets per quarter��33 Graph showing Landsat 7 lifetime geodetic accuracy per quarter��34

49. 50. 51. 52. 53.

Graph showing Landsat 7 band-average root mean square registration error since launch��34 Graph showing Landsat 7 lifetime orbital drift from World Reference System-2 (path 39, row 37)��35 Graph showing Landsat 7 lifetime orbital drift from World Reference System-2 (path 100, row 73)��36 Graph showing Libya 4 pseudoinvariant calibration site surface reflectance trending, Landsat 7 Enhanced Thematic Mapper Plus, Collection 2��37 Graph showing Libya 4 pseudoinvariant calibration site surface reflectance trending, Landsat 8 Operational Land Imager, Collection 2��37

Tables 1. 2. 3. 4. 5.

Landsat 8 Operational Land Imager radiometric performance summary, quarter 2, 2023��3 Landsat 8 Thermal Infrared Sensor radiometric performance summary, quarter 2, 2023��4 Landsat 8 Operational Land Imager typical radiances for each spectral band��4 Landsat 8 geometric performance summary, quarter 2, 2023��23 Landsat 7 geometric performance summary, quarter 2, 2023��32

Conversion Factors International System of Units to U.S. customary units

Multiply

To obtain

Length nanometer (nm)

0.00000003937

inch (in.)

meter (m)

3.281

foot (ft)

meter (m)

1.094

yard (yd)

kilometer (km)

0.6214

mile (mi)

Temperature in Kelvin (K) may be converted to degrees Celsius (°C) as follows: °C = K – 273.15.

Supplemental Information Radiance is given in watts per square meter per steradian per micrometer (W/m2 sr µm). Within this report, quarter 1 is from January to March, quarter 2 is from April to June, quarter 3 is from July to September, and quarter 4 is from October to December. For example, quarter 2, 2023, was from April to June 2023.

vii

Abbreviations Please refer to https://www.usgs.gov/core-science-systems/nli/landsat/glossary-and-acronyms for lists of Landsat glossary terms and other Landsat abbreviations. ~

approximately

ASTER

Advanced Spaceborne Thermal Emission and Reflection Radiometer

coastal/aerosol

Cal/Val

Calibration and Validation

CE90

circular error with 90-percent confidence

CNES

Centre National D’Etudes Spatiales

CPF

calibration parameter file

DOQ

digital orthophoto quadrangle

ECCOE

EROS Cal/Val Center of Excellence

Earth observation

EROS

Earth Resources Observation and Science

ETM+

Enhanced Thematic Mapper Plus

GCP

ground control point

GRI

Global Reference Image

L0Ra

Level 0 Reformatted Archive

L0Rp

Level 0 Reformatted Product

Level 1

L1C

Level-1C

L1TP

L1 Terrain Precision Correction

Ltypical

typical radiance

NEΔT

noise equivalent change in temperature

OLI

Operational Land Imager

PICS

pseudoinvariant calibration sites

RMSE

root mean square error

ROI

region of interest

SNR

signal-to-noise ratio

SPOT

Satellite Pour l’Observation de la Terre

SSM

Scene Select Mechanism

SWIR

shortwave infrared

TIRS

Thermal Infrared Sensor

USGS

U.S. Geological Survey

WRS–2

Worldwide Reference System-2

ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023 By Md Obaidul Haque,1 Rajagopalan Rengarajan,1 Mark Lubke,1 Md Nahid Hasan,1 Ashish Shrestha,1 Fatima Tuz Zafrin Tuli,1 Jerad L. Shaw,1 Alex Denevan,1 Shannon Franks,1 Kathryn Ruslander,1 Esad Micijevic,2 Michael J. Choate,2 Cody Anderson,2 Kurt Thome,3 Ed Kaita,4 Julia Barsi,4 Raviv Levy,4 Jeff Miller,4 and Leibo Ding4

Executive Summary

Introduction

The U.S. Geological Survey Earth Resources Observation and Science Calibration and Validation (Cal/Val) Center of Excellence (ECCOE) focuses on improving the accuracy, precision, calibration, and product quality of remote-sensing data, leveraging years of multiscale optical system geometric and radiometric calibration and characterization experience. The ECCOE Landsat Cal/Val Team continually monitors the geometric and radiometric performance of active Landsat missions and makes calibration adjustments, as needed, to maintain data quality at the highest level. This report provides observed geometric and radiometric analysis results for Landsats 7–8 for quarter 2 (April– June) of 2023. All data used to compile the Cal/Val analysis results presented in this report are freely available from the U.S. Geological Survey EarthExplorer website: https://ea rthexplorer.usgs.gov. One specific activity that the ECCOE Landsat Cal/Val Team closely monitored was a Landsat 8 Thermal Infrared Sensor (TIRS) Scene Select Mechanism (SSM) excursion anomaly. On April 21, 2023, a TIRS SSM excursion error flag was indicated in telemetry during a calibration activity when the SSM encoder was powered on and the mirror was between the nadir position and the deep space position. An initial recovery plan indicated the SSM was moving erratically, so the instrument was put into a safe state for additional troubleshooting. A second recovery plan was developed and successfully executed on April 23, 2023. Additional information about the Landsat 8 TIRS SSM excursion anomaly is available at https://www.usgs.gov/landsat-missions/news/ landsat-8-level-1-product-processing-resumes.

The U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Calibration and Validation (Cal/Val) Center of Excellence (ECCOE) focuses on improving the accuracy, precision, and quality of remote-sensing data, leveraging years of multiscale optical and thermal system geometric and radiometric calibration and characterization experience (USGS, 2021b). This report provides observed geometric and radiometric analysis results for Landsats 7–8 for quarter 2 (April–June) of 2023. All data used to compile the Cal/Val analysis results presented in this report are freely available from the USGS EarthExplorer website: https://earthexplorer.usgs.gov. One specific activity that the ECCOE Landsat Cal/Val Team closely monitored was a Landsat 8 Thermal Infrared Sensor (TIRS) Scene Select Mechanism (SSM) excursion anomaly. On April 21, 2023, a TIRS SSM excursion error flag was indicated in telemetry during a calibration activity when the SSM encoder was powered on and the mirror was between the nadir position and the deep space position. An initial recovery plan indicated the SSM was moving erratically, so the instrument was put into a safe state for additional troubleshooting. A second recovery plan was developed and successfully executed on April 23, 2023. Additional information about the Landsat 8 TIRS SSM excursion anomaly is available at https://www.usgs.gov/landsat-missions/news/ landsat-8-level-1-product-processing-resumes.

1KBR, Inc.; Work done under contract to the U.S. Geological Survey. 2U.S. Geological Survey. 3National Aeronautics and Space Administration. 4Science Systems and Applications, Inc.; Work done under contract to the National Aeronautics and Space Administration.

Background The U.S. Department of the Interior is directed to ensure that U.S. land imaging needs are met in the future and to maintain U.S. leadership in civil land imaging and land science. Those directives come in the context of the Future of Land Imaging Interagency Working Group’s report titled “A Plan for a U.S. National Land Imaging Program” (Executive Office of the President of the United States, 2007) and two recent Earth observation (EO) publications (Executive Office of the

2 ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023 President of the United States, 2014, 2016). These reports identified Landsat and other key USGS EO assets as critical components in the national EO structure, where several assets were ranked in the top 10 of more than 300 assets. Among them, Landsat ranked third or higher. Continuity with the past is key to meeting future land imaging science needs. The Landsat program, operated by the USGS, is the longest continuous record of satellitebased Earth imaging. Landsat data quality is viewed by the remote-sensing user community as a gold standard (National Geospatial Advisory Committee, 2020). To ensure the continued excellent quality of Landsat data, the USGS EROS Center has identified (1) maintaining a wellcalibrated multidecade remote-sensing archive for science and (2) developing and understanding land remote-sensing requirements and land imaging solutions as key strategic pillars. Understanding the land imaging requirements of current and future users, along with an ability to assess the capabilities of current and future systems for meeting those requirements, is key to meeting future land imaging science needs. In the past, Cal/Val activities at the EROS Center addressing the previously mentioned pillars were spread across multiple groups. The USGS EROS Center strategically brought the multiple groups together and formed a single team in a unified project called the ECCOE to enable the USGS to more efficiently address national and global land remote-sensing needs.

Purpose and Scope The primary purpose of this report is to provide the latest geometric and radiometric performance results for all active Landsat missions. This report provides observed geometric and radiometric analysis results for Landsats 7–8 for quarter 2 (April–June), 2023. All data used to compile the results presented in this report are available from the USGS EarthExplorer website: https://earthexplorer.usgs.gov (USGS, 2021a).

Processing Level Definitions This report frequently references Landsat processing levels. Descriptions of these processing levels are in the following subsections.

L0Ra files contain an entire interval of imagery, whereas L0Rp files only contain a smaller part of the L0Ra data: a Worldwide Reference System-2 (WRS–2) scene-based subset.

Level 1 The standard Level 1 (L1) image data are radiometrically and geometrically corrected. L1 Geometric Systematic Correction products are radiometrically calibrated with only systematic geometric corrections applied using the spacecraft ephemeris data. L1 Systematic Terrain Correction products are radiometrically calibrated with systematic geometric corrections applied using the spacecraft ephemeris data and digital elevation model data to correct for relief displacement. L1 Terrain Precision Correction (L1TP) products are radiometrically calibrated and orthorectified using ground control points (GCPs) and digital elevation model data to correct for relief displacement.

Level 2 The Level 2 science products are generated from L1 inputs that meet the less than 76-degree solar zenith angle constraint and include the required auxiliary data inputs to generate a scientifically viable product. Level 2 science products represent surface reflectance and surface temperature. Surface reflectance is the fraction of incoming solar radiation that is reflected from the Earth’s surface. Surface reflectance product generation accounts for the temporally, spatially, and spectrally varying scattering and absorbing effects of atmospheric gases, aerosols, and water vapor, which are necessary to reliably characterize the Earth’s land surface. Surface temperature is the measurement of the temperature of the surface of the Earth in Kelvin. Provisional surface temperature is generated from the Landsat Collection 2 L1 thermal infrared bands, top of atmosphere reflectance, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Emissivity Database data, ASTER Normalized Difference Vegetation Index data, and atmospheric profiles of geopotential height, specific humidity, and air temperature extracted from reanalysis data.

Level 0

Landsat Collection Definitions

The Level 0 Reformatted Archive (L0Ra) and Level 0 Reformatted Product (L0Rp) formats do not have sensor chip assembly or band alignment applied. L0Ra data are sensor data and spacecraft ancillary data that are reformatted for easier processing. Minor corrections to the ancillary data (such as frame number and time-code corrections) are applied, and ancillary raw data units are converted to engineering units. Image data are left in counts or digital numbers. L0Rp and L0Ra files are in the same format, but the content is different.

This report frequently references Landsat collections. In 2016, the USGS reorganized the Landsat archive into a tieredcollection management structure. This structure ensures that all Landsat L1 products provide a consistent archive of known data quality while controlling continuous improvement of the archive and access to all data as they are acquired. The implementation of collections represents a substantial change in the management of the Landsat archive by ensuring consistent quality over time and across all instruments.

Landsat 8 Radiometric Performance Summary 3

Landsat Collection 1 Landsat Collection 1 was released in 2016 and introduced collection tiers for L1 data products based on data quality and the level of processing. The tier definition purpose was to support easier identification of suitable scenes for timeseries pixel-level analysis. In addition to tiered products, several changes were first introduced with the release of Collection 1 processing. Because of the release of Landsat Collection 2 in December 2020, Collection 1 processing of newly acquired data ended on January 1, 2022. Access to archived Collection 1 data products ceased on December 30, 2022. Additional information about the Collection 1 products is available at https://www.usgs.gov/core-science-systems/nli/ landsat/landsat-collection-1.

information about the Collection 2 products is available at https://www.usgs.gov/core-science-systems/nli/landsat/ landsat-collection-2.

Landsat 8 Radiometric Performance Summary The Landsat 8 on-orbit radiometric performance for this reporting quarter (quarter 2, April–June 2023) meets all requirements as outlined in USGS (2019b). The quarterly Operational Land Imager (OLI) and TIRS radiometric performance summaries are provided in tables 1 and 2, respectively.

Operational Land Imager Signal-to-Noise Ratio

Landsat Collection 2 Landsat Collection 2 was released in December 2020 and marked the second major reprocessing effort on the Landsat archive (USGS, 2020a, b). Collection 2 represented several data product improvements that harnessed recent advancements in data processing, algorithm development, and data access and distribution capabilities. Additional

The signal-to-noise ratio (SNR) for each of the OLI spectral bands is characterized at a prescribed band-specific typical radiance (Ltypical) level, as described in table 3. The SNR of a detector at a given radiance level is defined as the mean of the measured pixel radiances acquired over a homogenous target divided by their standard deviation. A curve is fit to the SNR at the measured radiance levels and is evaluated at the prescribed

Table 1. Landsat 8 Operational Land Imager radiometric performance summary, quarter 2 (April–June), 2023. [The previous quarter is quarter 1 (January–March), 2023. OLI, Operational Land Imager; <, less than; SNR, signal-to-noise ratio; Ltypical, typical radiance; -, not applicable; Lhigh, high radiance; RMS, root mean square; stdev, standard deviation; ≤, less than or equal to; W/m2 sr µm, watt per square meter per steradian per micrometer; σ, sigma; spec, specification]

Requirement OLI ghosting OLI absolute radiance uncertainty OLI absolute reflectance uncertainty

Measured value from this quarter

Measured value from previous quarter1

Meets

Required value Varies

OLI median SNR Ltypical

Meets

Varies

OLI median SNR Lhigh

Meets

Varies

Unit Percent

Percent

Percent -

OLI uniformity full field of view

0.35

<0.5

Percent

OLI uniformity banding RMS

0.80

Percent

OLI uniformity banding stdev

0.15

<0.25

Percent

≤0.5, 1

Percent

OLI uniformity streaking

0.5

OLI coherent noise

Meets

Less than coherent noise threshold curve

OLI saturation radiances

Meets

Varies

W/m2 sr µm

OLI 16-day radiometric stability

0.12

Percent (2σ)

OLI 60-second radiometric stability

0.1

<0.5

Percent (2σ)

OLI inoperable detectors

<0.1

Percent

OLI out-of-spec detectors

0.06

<0.25

Percent

1From Haque and others (2023).

4 ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023 Table 2. Landsat 8 Thermal Infrared Sensor radiometric performance summary, quarter 2 (April–June), 2023. [The previous quarter is quarter 1 (January–March), 2023. TIRS, Thermal Infrared Sensor; ~, approximately; <, less than; NE∆T, noise equivalent change in temperature; K, Kelvin; TBD, to be determined; RMS, root mean square; stdev, standard deviation; -, not applicable; >, greater than; W/m2 sr µm, watt per square meter per steradian per micrometer; σ, sigma; spec, specification]

Requirement

Measured value from this quarter

Measured value from previous quarter1

Required value

Percent

0.05

TIRS absolute radiance uncertainty TIRS NE∆T (at 300 K)

0.05

Unit

<0.4

TIRS uniformity full field of view

TBD

<0.5

Percent

TIRS uniformity banding RMS

TBD

<0.5

Percent

TIRS uniformity banding stdev

TBD

<0.5

Percent

<0.5

Percent

TIRS uniformity streaking

<0.5

TIRS coherent noise

<0.5

Meets

Less than coherent noise threshold curve

TIRS saturation radiances

28.4, 19.2

>20.5, >17.8

W/m2 sr µm

TIRS 40-minute radiometric stability

0.1

<0.7

Percent (1σ)

TIRS inoperable detectors

<0.1

Percent

TIRS out-of-spec detectors

0.21

<0.25

Percent

1From Haque and others (2023).

Table 3. Landsat 8 Operational Land Imager typical radiances for each spectral band. [OLI, Operational Land Imager; nm, nanometer; Ltypical, typical radiance; W/m2 sr µm, watt per square meter per steradian per micrometer]

OLI band number

Spectral band

Center wavelength (nm)

Ltypical (W/m2 sr µm)

Coastal/aerosol

443

Blue

482

Green

561

Red

655

Near infrared

865

Shortwave infrared 1

1,609

4.0

Shortwave infrared 2

2,201

1.7

Panchromatic

590

Cirrus

1,373

6.0

Ltypical level. The SNR is characterized at multiple stages of the instrument build, culminating in the testing of the fully integrated instrument. The OLI SNR is evaluated on orbit each month. It remains consistently two to three times better than requirements and about eight times better than the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) SNR. The Collection 2 SNR slightly increased because of improvement in the bias calculation, further exceeding requirement thresholds. The per-band OLI median SNR at the Ltypical level

(yellow bars) for June 2023, which for all bands easily exceeds the OLI SNR requirements (blue bars) by more than 50 percent, is shown in figure 1. Lifetime SNR stability at Ltypical for each OLI band is represented in figures 2, 3, 4, 5, 6, 7, 8, 9, and 10; monthly SNR values (for the detectors that have median SNRs for all bands) are denoted by the diamonds, and the uncertainties in the monthly SNR model are denoted by the error bars. The SNR for each band has remained stable over time (within the uncertainty of the models and much greater than the required levels).

Landsat 8 Radiometric Performance Summary 5 450 400

Signal-to-noise ratio

350 300 250 200 150 100 50 0 Coastal/aerosol

Blue

Green

Red

Near infrared

Shortwave infrared 1

Shortwave infrared 2

Panchromatic

Cirrus

Spectral band EXPLANATION Operational Land Imager (OLI) signal-to-noise ratio (SNR) requirement at typical radiance (Ltypical )

Standard deviation

Median SNR at Ltypical for June 2023 1.5 × OLI SNR requirement at Ltypical

Figure 1. Landsat 8 Operational Land Imager signal-to-noise ratio performance, June 2023.

240

Coastal/aerosol

Signal-to-noise ratio

239

238

237

236

235 Dec. 2012

Dec. 2013

Dec. 2014

Dec. 2015

Dec. 2016

Dec. 2017

Dec. 2018

Dec. 2019

Dec. 2020

Dec. 2021

Evaluation period EXPLANATION Monthly signal-to-noise ratio (SNR) of the detector with the band median SNR at typical radiance (Ltypical ) +2 × uncertainty of noise model Median −2 × uncertainty of noise model

Figure 2. Landsat 8 Operational Land Imager coastal/aerosol band lifetime signal-to-noise ratio stability.

Dec. 2022

6 ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023

373

Blue

Signal-to-noise ratio

372

371

370

369 Dec. 2012

Dec. 2013

Dec. 2014

Dec. 2015

Dec. 2016

Dec. 2017

Dec. 2018

Dec. 2019

Dec. 2020

Dec. 2021

Dec. 2022

Dec. 2021

Dec. 2022

Figure 3. Landsat 8 Operational Land Imager blue band lifetime signal-to-noise ratio stability.

309

Green

Signal-to-noise ratio

308

307

306

305 Dec. 2012

Dec. 2013

Dec. 2014

Dec. 2015

Dec. 2016

Dec. 2017

Dec. 2018

Dec. 2019

Dec. 2020

Figure 4. Landsat 8 Operational Land Imager green band lifetime signal-to-noise ratio stability.

Landsat 8 Radiometric Performance Summary 7

Signal-to-noise ratio

231

Red

230

229

228 Dec. 2012

Dec. 2013

Dec. 2014

Dec. 2015

Dec. 2016

Dec. 2017

Dec. 2018

Dec. 2019

Dec. 2020

Dec. 2021

Dec. 2022

Dec. 2021

Dec. 2022

Figure 5. Landsat 8 Operational Land Imager red band lifetime signal-to-noise ratio stability.

205

Near infrared

Signal-to-noise ratio

204

203

202

201 Dec. 2012

Dec. 2013

Dec. 2014

Dec. 2015

Dec. 2016

Dec. 2017

Dec. 2018

Dec. 2019

Dec. 2020

Figure 6. Landsat 8 Operational Land Imager near infrared band lifetime signal-to-noise ratio stability.

8 ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023

271

Shortwave infrared 1

Signal-to-noise ratio

270

269

268

267

266

265 Dec. 2012

Dec. 2013

Dec. 2014

Dec. 2015

Dec. 2016

Dec. 2017

Dec. 2018

Dec. 2019

Dec. 2020

Dec. 2021

Dec. 2022

Figure 7. Landsat 8 Operational Land Imager shortwave infrared 1 band lifetime signal-to-noise ratio stability.

331

Shortwave infrared 2

330

Signal-to-noise ratio

329 328 327 326 325 324 Dec. 2012

Dec. 2013

Dec. 2014

Dec. 2015

Dec. 2016

Dec. 2017

Dec. 2018

Dec. 2019

Dec. 2020

Dec. 2021

Figure 8. Landsat 8 Operational Land Imager shortwave infrared 2 band lifetime signal-to-noise ratio stability.

Dec. 2022

Landsat 8 Radiometric Performance Summary 9

163

Cirrus

Signal-to-noise ratio

162

161

160

159

158

157 Dec. 2012

Dec. 2013

Dec. 2014

Dec. 2015

Dec. 2016

Dec. 2017

Dec. 2018

Dec. 2019

Dec. 2020

Dec. 2021

Dec. 2022

Dec. 2021

Dec. 2022

Figure 9. Landsat 8 Operational Land Imager cirrus band lifetime signal-to-noise ratio stability.

151

Panchromatic

Signal-to-noise ratio

150

149

148

147

146 Dec. 2012

Dec. 2013

Dec. 2014

Dec. 2015

Dec. 2016

Dec. 2017

Dec. 2018

Dec. 2019

Dec. 2020

Figure 10. Landsat 8 Operational Land Imager panchromatic band lifetime signal-to-noise ratio stability.

10 ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023

Thermal Infrared Sensor Noise Performance Noise can be defined as variation in detected signal over time when observing a stable source of radiation. For thermal sensors, noise is usually expressed in terms of a change in brightness temperature (that is, the noise equivalent change in temperature [NEΔT]). NEΔT is estimated as the standard deviation of detector data acquired over a uniform radiance source and then converted to temperature. Noise performance is completed on blackbody and deep space TIRS data (Montanaro and others, 2014). All TIRS detectors have similar NEΔT. At 300 Kelvin (K), band-average noise performance for both thermal bands is about eight times better than the requirement (less than 0.4 K) and about four times better than the NEΔT of the Landsat 7 ETM+ thermal band at that same temperature. Lifetime averages of NEΔT at 300 K for TIRS band 10 are shown in figure 11, and the same averages for TIRS band 11 are shown in figure 12. In both figures, colored diamonds are used to indicate the observed NEΔT values as measured over time.

Radiometric Stability

Noise equivalent change in temperature (at 300 Kelvin), in Kelvin

Radiometric stability of an instrument is fundamental to low uncertainty in the radiometric calibration of data products generated from its measurements. The radiometric response stability is characterized for all OLI and TIRS bands using the instruments’ responses to signals from the onboard calibration

0.06

devices collected over time (USGS, 2021d). The bias and gain stability of an instrument are contributing factors to variability within a radiometrically calibrated product. The per-band OLI radiometric stability over the lifetime of the instrument is shown in figures 13, 14, 15, 16, 17, 18, 19, 20, and 21. Within each figure, the x-axis represents years since launch (February 11, 2013) and the y-axis represents the response relative to mission day 75. The solid brown line (figs. 13 and 14) represents the gain model used over time, which is derived from the OLI response to the stimulation lamps, solar panels, and lunar collects; it is only shown for the bands with responsivity (gain) determined to be slowly changing over time (coastal/aerosol [CA] and blue bands). For the remaining bands, response changes were minuscule until the safehold events in November 2020. More information about the Landsat 8 safehold events is available at https://www .usgs.gov/landsat-missions/november-19-2020-landsat-8-data- availability-update-recent-safehold-events. These observations indicate high radiometric stability of the instrument over its lifetime. Data derived from bands that have changed responsivity are corrected during product generation, so final products are not affected. From Micijevic and others (2021), the stability of the TIRS side A electronics that were used for the first approximately (~) 700 days of the mission is shown in figures 22 and 23. During that period, TIRS gains changed by about 0.2 and 0.1 percent per year for bands 10 and 11, respectively. These trends reduced on the side B electronics to about 0.05 and 0.01 percent until the two safehold events in November 2020, as seen in figures 24 and 25, respectively. After the safehold events, TIRS responsivity has gradually decreased ~3.0 and

Band 10

0.055

0.05

0.045

0.04 Jan. 2013

June 2014

Oct. 2015

Mar. 2017

July 2018

Dec. 2019

Date EXPLANATION Observed average

Figure 11. Landsat 8 Thermal Infrared Sensor band 10 lifetime noise performance.

Apr. 2021

Aug. 2022

Noise equivalent change in temperature (at 300 Kelvin), in Kelvin

Landsat 8 Radiometric Performance Summary 11

0.06

Band 11

0.055

0.05

0.045

0.04 Jan. 2013

June 2014

Oct. 2015

Mar. 2017

July 2018

Dec. 2019

Apr. 2021

Aug. 2022

Date EXPLANATION Observed average

Figure 12. Landsat 8 Thermal Infrared Sensor band 11 lifetime noise performance.

Response relative to mission day 75, in percent

1.01

Coastal/aerosol

1.005 1 0.995 0.99 0.985 0.98 0.975 0.97 0.965 0.96 0

Years since launch (February 11, 2013) EXPLANATION Gain model

Stimulation (stim) lamp—Working

Solar panel—Working

Stim lamp—Pristine

Stim lamp—Backup

Solar panel—Pristine

Lunar

Figure 13. Landsat 8 Operational Land Imager coastal/aerosol band lifetime radiometric stability.

12 ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023

Response relative to mission day 75, in percent

1.01

Blue

1.005 1 0.995 0.99 0.985 0.98 0.975 0.97 0.965 0

Years since launch (February 11, 2013) EXPLANATION Gain model

Stimulation (stim) lamp—Working

Solar panel—Working

Stim lamp—Pristine

Stim lamp—Backup

Solar panel—Pristine

Lunar

Figure 14. Landsat 8 Operational Land Imager blue band lifetime radiometric stability.

Response relative to mission day 75, in percent

1.01

Green

1.005 1 0.995 0.99 0.985 0.98 0.975 0.97 0.965 0

Years since launch (February 11, 2013) EXPLANATION Stimulation (stim) lamp—Working

Solar panel—Working

Stim lamp—Pristine

Stim lamp—Backup

Solar panel—Pristine

Lunar

Figure 15. Landsat 8 Operational Land Imager green band lifetime radiometric stability.

Landsat 8 Radiometric Performance Summary 13 Red

Response relative to mission day 75, in percent

1.01 1.005 1 0.995 0.99 0.985 0.98 0.975 0.97 0.965

Years since launch (February 11, 2013) EXPLANATION Stimulation (stim) lamp—Working

Solar panel—Working

Stim lamp—Pristine

Stim lamp—Backup

Solar panel—Pristine

Lunar

Figure 16. Landsat 8 Operational Land Imager red band lifetime radiometric stability.

Response relative to mission day 75, in percent

1.01

Near infrared

1.005 1 0.995 0.99 0.985 0.98 0.975 0.97 0.965 0

Years since launch (February 11, 2013) EXPLANATION Stimulation (stim) lamp—Working

Solar panel—Working

Stim lamp—Pristine

Stim lamp—Backup

Solar panel—Pristine

Lunar

Figure 17. Landsat 8 Operational Land Imager near infrared band lifetime radiometric stability.

14 ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023

Response relative to mission day 75, in percent

1.01

Shortwave infrared 1

1.005 1 0.995 0.99 0.985 0.98 0.975 0.97 0.965 0

Years since launch (February 11, 2013) EXPLANATION Stimulation (stim) lamp—Working

Solar panel—Working

Stim lamp—Pristine

Stim lamp—Backup

Solar panel—Pristine

Lunar

Figure 18. Landsat 8 Operational Land Imager shortwave infrared 1 band lifetime radiometric stability. Shortwave infrared 2

Response relative to mission day 75, in percent

1.01 1.005 1 0.995 0.99 0.985 0.98 0.975 0.97 0.965 0

Years since launch (February 11, 2013) EXPLANATION Stimulation (stim) lamp—Working

Solar panel—Working

Stim lamp—Pristine

Stim lamp—Backup

Solar panel—Pristine

Lunar

Figure 19. Landsat 8 Operational Land Imager shortwave infrared 2 band lifetime radiometric stability.

Landsat 8 Radiometric Performance Summary 15

Response relative to mission day 75, in percent

1.01

Panchromatic

1.005 1 0.995 0.99 0.985 0.98 0.975 0.97 0.965 0

Years since launch (February 11, 2013) EXPLANATION Stimulation (stim) lamp—Working

Solar panel—Working

Stim lamp—Pristine

Stim lamp—Backup

Solar panel—Pristine

Lunar

Figure 20. Landsat 8 Operational Land Imager panchromatic band lifetime radiometric stability.

Response relative to mission day 75, in percent

1.01

Cirrus

1.005 1 0.995 0.99 0.985 0.98 0.975 0.97 0.965 0

Years since launch (February 11, 2013) EXPLANATION Stimulation (stim) lamp—Working

Solar panel—Working

Stim lamp—Pristine

Stim lamp—Backup

Solar panel—Pristine

Lunar

Figure 21. Landsat 8 Operational Land Imager cirrus band lifetime radiometric stability.

16 ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023

353.5

Band 10, side A

353

Gain

352.5

352

351.5

351

350.5 0

Years since launch (February 11, 2013) EXPLANATION Gain in digital number divided by watt per square meter per steradian per micrometer (DN/[W/m2 sr µm])

Figure 22. Landsat 8 Thermal Infrared Sensor band 10 radiometric stability (side A).

495.5

Band 11, side A

495

Gain

494.5

494

493.5

493

492.5 0

Years since launch (February 11, 2013) EXPLANATION Gain in digital number divided by watt per square meter per steradian per micrometer (DN/[W/m2 sr µm])

Figure 23. Landsat 8 Thermal Infrared Sensor band 11 radiometric stability (side A).

Landsat 8 Radiometric Performance Summary 17

330

Band 10, side B

328 326 324

Gain

322 320 318 316 314 312 310 2

Years since launch (February 11, 2013) EXPLANATION Gain in digital number divided by watt per square meter per steradian per micrometer (DN/[W/m2 sr µm])

Figure 24. Landsat 8 Thermal Infrared Sensor band 10 radiometric stability (side B). Band 11, side B 415

Gain

410

405

400

395

390 2

Years since launch (February 11, 2013) EXPLANATION Gain in digital number divided by watt per square meter per steradian per micrometer (DN/[W/m2 sr µm])

Figure 25. Landsat 8 Thermal Infrared Sensor band 11 radiometric stability (side B).

18 ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023 ~6.0 percent for bands 10 and 11, respectively. Note that the response degradation is modeled and corrected to within 0.5-percent uncertainty in the L1 products. Since January 2021, TIRS onboard calibrator acquisitions have been collected on a weekly basis (instead of once every ~2 weeks) to better monitor the degradation in response observed after the safehold events. Weekly calibration acquisitions are planned into the future if the response degradation trend continues, and if geometric and radiometric accuracies are not negatively affected by the increased acquisition frequency.

implemented for the blue band in April 2017. In April 2018, it was determined that the response to the working stimulation lamp was diverging from the other calibrators, and the working stimulation lamp was removed from the model that generates the gain updates. Similarly, in October 2019, the working diffuser was removed from the gain model because of diverging trends. In both cases, the new estimates of the radiometric gain were only applied to newly acquired data. When the archive was reprocessed for Collection 2, the updated gains were applied to all data, which changed the calibrated response in the CA and blue bands by as much as 0.15 percent compared to the Collection 1 products. The safehold events in November 2020 caused small changes to the OLI response, as reflected in figure 26 by the small, systematic error adjustments that were made to the gain models. In July 2021, the calibration parameter file (CPF) was updated to account for as much as a 0.12-percent step change in OLI responsivity caused by the November 2020 safehold events. The effect of change in average gain for TIRS bands 10 and 11 since the safehold event on November 1, 2020, is shown in figure 27. The orange line is a modeled gain trend for band 10 based on the Internal Calibrator data (fig. 24), and the blue line is the gain trend sampled into calibration parameters that ensure there is no more than a 0.5-percent bandaverage radiometric gain change over the CPF period in the L1 products. Likewise, for band 11, the magenta line is a modeled gain trend based on the Internal Calibrator data (fig. 25), and the yellow line is the gain trend sampled into calibration parameters. Because of the relatively sharp decrease in response shortly after the safehold events, when compared

Updates to Absolute Radiometric Calibration Absolute radiometric calibration is established on the ground before launch and transferred to orbit using the solar diffuser for OLI and the blackbody for TIRS. Onboard calibrators and pseudoinvariant calibration sites (PICS; Committee on Earth Observation Satellites, 2021) are used to monitor changes in absolute calibration, and vicarious methods are used to check absolute calibration over time (USGS, 2021d). Updates can be made to the calibration parameters used in processing the data to L1 when a substantial change is detected in the calibrator trends. The lifetime effect of OLI gain updates is shown in figure 26. A slow decay in CA and blue band calibration response was observed (figs. 13 and 14). The absolute radiometric calibration for the CA band has been actively modeled since April 2015, and an update to the calibration parameters was 0.2

Calibration parameter file implementation of gain models, July 1, 2021

Gain change, in percent

Safehold event, November 1, 2020

−0.2 −0.4 −0.6 −0.8 −1 −1.2 0

Years since launch (February 11, 2013) EXPLANATION Gain model Coastal/aerosol band Red band Shortwave infrared 1 band

Blue band Near infrared band Shortwave infrared 2 band

Green band Panchromatic band Cirrus band

Calibration parameter file gain Blue band Coastal/aerosol band

Figure 26. Landsat 8 Operational Land Imager lifetime gain trends and calibration gain updates.

Landsat 8 Radiometric Performance Summary 19

1.01

Calibration period

Safehold event, November 1, 2020

Gain ratio

0.99

0.98

0.97

0.96

0.95

0.94 7.6

8.1

8.6

9.1

9.6

10.1

Years since launch (February 11, 2013) EXPLANATION Band 10 Gain trend Calibration parameter file gain Band 11 Gain trend Calibration parameter file gain

Figure 27.

Landsat 8 Thermal Infrared Sensor gain degradation since the safehold event on November 1, 2020.

with the response before the safehold events, calibration parameters were issued more frequently to ensure high quality L1 products. As the rate of degradation has slowed, updated calibration parameters have returned to quarterly issuance.

Relative Gains Relative gains account for the differences in responsivity between detectors within a spectral band. OLI relative gains are monitored using solar diffuser acquisitions, side slither acquisitions (which entail a 90-degree yaw maneuver over an invariant site to flatten the data), and scene statistics. Quarterly updates are completed using data from the solar diffuser acquisitions from quarter 1 (January–March), 2023. Starting with the release of Collection 2, TIRS relative gain calibration updates also were completed quarterly using blackbody collects from the previous quarter. These calibration updates removed detector-to-detector striping (USGS, 2021d).

Typical per-detector changes in relative gains between the previous quarter and this quarter for several bands are shown in figures 28, 29, 30, and 31 by analyzing data from within each quarter. In each figure, the x-axis indicates the detector number, and the y-axis indicates the change in relative gain between the quarters as a ratio. These changes in responsivity are accounted for in the L1 product by updating the following quarter’s CPF. The OLI detectors that have indicated a sudden change in responsivity of 0.5 percent or greater in the shortwave infrared (SWIR) 1 and SWIR 2 bands since launch are shown in figures 32 and 33. The x-axis indicates the date of the jump in responsivity, and the y-axis signifies the detector number. The observed responsivity jumps seem to be randomly scattered in time and location on the focal plane so do not seem to be associated with an instrument event or failure. These jumps are only seen in the SWIR bands (SWIR 1, SWIR 2, and cirrus); the visible and near infrared band detectors have not indicated any jump behavior over the whole mission.

20 ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023

1.002

Relative gain ratio

0.998

0.996

Largest change: 0.073 percent

0.994

1,000

2,000

3,000

4,000

5,000

6,000

Detector index

Figure 28. Landsat 8 Operational Land Imager coastal/aerosol band per-detector change in relative gains between quarter 1 and quarter 2, 2023.

1.008

Relative gain ratio

1.006

1.004

1.002

0.998

Largest change: 0.561 percent 0.996 0

1,000

2,000

3,000

4,000

5,000

6,000

Detector index

Figure 29. Landsat 8 Operational Land Imager shortwave infrared 1 band per-detector change in relative gains between quarter 1 and quarter 2, 2023.

Landsat 8 Radiometric Performance Summary 21

Relative gain ratio

1.010

1.005

Largest change: 0.360 percent

Largest change: 0.422 percent

0.995

1,000

2,000

3,000

4,000

5,000

6,000

Detector index

Figure 30. Landsat 8 Operational Land Imager shortwave infrared 2 band per-detector change in relative gains between quarter 1 and quarter 2, 2023.

1.002

Relative gain ratio

1.001

0.999

0.998

0.997

Largest change: 0.098 percent 0.996 0

2,000

4,000

6,000

8,000

10,000

12,000

Detector index

Figure 31. Landsat 8 Operational Land Imager panchromatic band per-detector change in relative gains between quarter 1 and quarter 2, 2023.

22 ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023

7,410

Shortwave infrared 1

6,916 6,422 5,928

Detector number

5,434 4,940 4,446 3,952 3,458 2,964 2,470 1,976 1,482 988 494 0 Oct. 3, 2013

Feb. 15, 2015

June 29, 2016

Nov. 11, 2017

Mar. 26, 2019

Aug. 7, 2020

Dec. 20, 2021

May 4, 2023

Date EXPLANATION Observed detector response jump

Figure 32. Landsat 8 Operational Land Imager shortwave infrared 1 lifetime jumps in detector responsivity.

7,410

Shortwave infrared 2

6,916 6,422 5,928 5,434

Detector number

4,940 4,446 3,952 3,458 2,964 2,470 1,976 1,482 988 494 0 Oct. 3, 2013

Feb. 15, 2015

June 29, 2016

Nov. 11, 2017

Mar. 26, 2019

Aug. 7, 2020

Dec. 20, 2021

Date EXPLANATION Observed detector response jump

Figure 33. Landsat 8 Operational Land Imager shortwave infrared 2 lifetime jumps in detector responsivity.

May 4, 2023

Landsat 8 Geometric Performance Summary 23

Landsat 8 Geometric Performance Summary The Landsat 8 on-orbit geometric performance for the reporting quarter (quarter 2, April–June 2023) meets all requirements as outlined in USGS (2019b). The quarterly results summary is provided in table 4.

Band Registration Accuracy Internal band registration measures how accurately the various Landsat 8 spectral bands are geometrically aligned to each other. The assessment provides a numerical evaluation of the accuracy of the band registration within an image using automated cross-correlation techniques between the bands to be assessed (USGS, 2021d). OLI band registration performance has been stable over time. Quarterly band-to-band maximum registration accuracy for each band combination except for the cirrus band is shown in figure 34. Within the figure, blue bars indicate maximum registration accuracy in the line direction, and green bars indicate maximum registration accuracy in the sample direction. Lifetime OLI band registration accuracy for all bands is 4.2 meters (not shown), and lifetime OLI band registration accuracy for all bands, excluding cirrus, is 3.3 meters, which is well within the instrument specification accuracy. OLI band registration accuracy for all bands during quarter 2, 2023, is

4.4 meters (not shown), and OLI band registration accuracy for all bands, excluding cirrus, during quarter 2, 2023, is 3.3 meters. TIRS band registration performance has been stable throughout the instrument’s lifetime, including after changes in SSM operation beginning in December 2014. Behavior is well within specification, as shown in figure 35, and quarter 2, 2023, results are consistent with past performance. Within the figure, blue bars indicate maximum registration accuracy in the line direction, and green bars indicate maximum registration accuracy in the sample direction. Lifetime TIRS band registration accuracy is 9.0 meters, and during quarter 2, 2023, the accuracy is 8.7 meters. Since quarter 3 (July–September), 2020 (Collection 2 data), registration bias between the line and sample directions has reduced, which may be because of better SSM pointing stability, the TIRS relative gain update, or both. Lifetime TIRS to OLI band registration accuracy by quarter is shown in figure 36. Before the Collection 2 CPF update, seasonal effects are noticeable but leveled off after the release of Collection 2 in December 2020, as indicated by the closely aligned line (blue bars) and sample (green bars) accuracies. From Haque and others (2023), alignment offset was greater for quarter 2 and quarter 3, 2022, because of changes in the alignment trends between the two instruments. Lifetime TIRS to OLI registration accuracy (excluding the cirrus band) is 19.6 meters in the line direction and 18.0 meters in the sample direction. Quarter 2, 2023, TIRS to OLI registration accuracy (excluding the cirrus band) is 18.1 meters in the line direction and 16.9 meters in the sample direction.

Table 4. Landsat 8 geometric performance summary, quarter 2 (April–June), 2023. [The previous quarter is quarter 1 (January–March), 2023. OLI, Operational Land Imager; <, less than; LE90, linear error with 90-percent confidence; CE90, circular error with 90-percent confidence; L1T, Level 1 terrain-corrected product; >, greater than; TIRS, Thermal Infrared Sensor]

Measured value from this quarter

Measured value from previous quarter1

Required value

OLI band registration accuracy (all bands)

4.40

3.95

<4.5

Meter (LE90)

OLI band registration accuracy (no cirrus)

3.30

3.13

<4.5

Meter (LE90)

Absolute geodetic accuracy

23.1

28.9

<65

Meter (CE90)

Relative geodetic accuracy

7.5

14.0

<25

Meter (CE90)

Geometric (L1T) accuracy

11.5

13.4

<12

Meter (CE90)

OLI edge slope

0.030

>0.027

1 per meter

TIRS band registration accuracy

8.7

8.5

<18

Meter (LE90)

TIRS-to-OLI registration accuracy

18.1

18.0

<30

Meter (LE90)

Requirement

1From Haque and others (2023).

Unit

Linear error with 90-percent confidence, in meters 0

0 2013Q2 2013Q3 2013Q4 2014Q1 2014Q2 2014Q3 2014Q4 2015Q1 2015Q2 2015Q3 2015Q4 2016Q1 2016Q2 2016Q3 2016Q4 2017Q1 2017Q2 2017Q3 2017Q4 2018Q1 2018Q2 2018Q3 2018Q4 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 2020Q2 2020Q3 2020Q4 2021Q1 2021Q2 2021Q3 2021Q4 2022Q1 2022Q2 2022Q3 2022Q4 2023Q1 2023Q2 All

2013Q2 2013Q3 2013Q4 2014Q1 2014Q2 2014Q3 2014Q4 2015Q1 2015Q2 2015Q3 2015Q4 2016Q1 2016Q2 2016Q3 2016Q4 2017Q1 2017Q2 2017Q3 2017Q4 2018Q1 2018Q2 2018Q3 2018Q4 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 2020Q2 2020Q3 2020Q4 2021Q1 2021Q2 2021Q3 2021Q4 2022Q1 2022Q2 2022Q3 2022Q4 2023Q1 2023Q2 All

Linear error with 90-percent confidence, in meters

24 ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023 Operational Land Imager

3.5

2.5

1.5

0.5

Calendar year and quarter (Q) EXPLANATION

Maximum registration accuracy Line direction

Line direction Sample direction

Figure 34. Operational Land Imager lifetime band (excluding cirrus) registration accuracy by quarter.

Thermal Infrared Sensor

Calendar year and quarter (Q)

EXPLANATION

Maximum registration accuracy

Sample direction

Figure 35. Landsat 8 Thermal Infrared Sensor lifetime band registration accuracy by quarter.

Thermal Infrared Sensor to Operational Land Imager

Linear error with 90-percent confidence, in meters

Landsat 8 Geometric Performance Summary 25

Calendar year and quarter (Q) EXPLANATION Maximum registration accuracy Line direction

Sample direction

Figure 36. Landsat 8 Thermal Infrared Sensor to Operational Land Imager lifetime band (excluding cirrus) registration accuracy by quarter.

Operational Land Imager to Thermal Infrared Sensor Alignment OLI to TIRS alignment knowledge is critical to ensure that the L1 product accuracy requirements can be met. The alignment between OLI and TIRS instruments is periodically measured using correlation-based methods to ensure that the band-to-band alignment requirements for all Landsat 8 bands can be met (USGS, 2021d). The alignment estimates are used to update the calibration parameters in the CPFs when the observed changes are determined to affect the performance requirements. TIRS to OLI pitch alignment measurements over instrument lifetimes are shown in figure 37. The November 2020 safehold events did substantially affect pitch alignment, but the ECCOE Landsat Cal/Val Team continues to monitor pitch alignment. From Haque and others (2022), in quarter 4, 2021, a small change in the TIRS to OLI pitch alignment was observed, which is similar to the seasonal trend observed in previous years; however, the magnitude of this trend was not the same as before, so it was unclear whether this new trend would continue or not. The trend continued in quarter 1, so a CPF update was issued in quarter 2, 2022, for residual corrections to the alignment parameters. At this point of time, predictive estimates based on previous quarters, not knowing if the seasonal trend will be observed or not, made the CPF inconsistent with the seasonal pattern. With an intention to align the CPF more with the seasonal pattern for better prediction,

subsequent predictive CPF updates for quarter 3, 2022, and quarter 4, 2022, were not changed. The April 2023 TIRS SSM excursion anomaly did not show any substantial effects in the TIRS to OLI pitch alignment. The lifetime TIRS to OLI roll alignment is shown in figure 38, and the lifetime TIRS to OLI yaw alignment is shown in figure 39. The April 2023 TIRS SSM excursion anomaly did not show any substantial effects to roll or yaw alignment. Each light blue symbol on these figures represents one calibration scene, the dark blue solid lines indicate quarterly alignment averages, and the orange dashed lines indicate applied Collection 2 CPF correction values.

Geometric Accuracy The Landsat 8 geometric assessment evaluates the absolute positional accuracy of the image products with respect to a ground (geometric) reference. The geometric accuracy assessment estimates the geometric error between the L1TP products and GCPs using automated cross-correlation techniques (USGS, 2021d). Based on analysis results, relative accuracy of the Collection 2 GCPs is comparable to the digital orthophoto quadrangle (DOQ) supersites, which are sites created from a mosaic of highly accurate high-resolution terraincorrected aerial data. Comparatively, relative accuracy of the Collection 2 GCPs is substantially better than the internal consistency of the Collection 1 GCPs. Overall, cloud contaminated scene-based results are the primary contributor to poor

26 ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023

0.00024

Pitch

0.00023

Pitch angle, in radians

0.00022 0.00021 0.0002 0.00019 0.00018 0.00017 0.00016 0.00015 Mar. 1, 2013

Mar. 1, 2014

Mar. 1, 2015

Mar. 1, 2016

Mar. 1, 2017

Mar. 1, 2018

Mar. 1, 2019

Mar. 1, 2020

Mar. 1, 2021

Mar. 1, 2022

Mar. 1, 2023

Date EXPLANATION Pitch estimated from a quarterly average

Pitch in the calibration parameter file

Pitch estimated from calibration scene

Figure 37. Landsat 8 Thermal Infrared Sensor to Operational Land Imager lifetime pitch alignment.

0.00172

Roll

Roll angle, in radians

0.00171

0.0017

0.00169

0.00168

0.00167

0.00166 Mar. 1, 2013

Mar. 1, 2014

Mar. 1, 2015

Mar. 1, 2016

Mar. 1, 2017

Mar. 1, 2018

Mar. 1, 2019

Mar. 1, 2020

Mar. 1, 2021

Mar. 1, 2022

Mar. 1, 2023

Date EXPLANATION Roll estimated from a quarterly average

Roll in the calibration parameter file

Roll estimated from calibration scene

Figure 38. Landsat 8 Thermal Infrared Sensor to Operational Land Imager lifetime roll alignment.

geometric accuracy from L1TP products. Lifetime quarterly geometric accuracy at a circular error with 90-percent confidence (CE90) is shown in figure 40. Blue bars indicate the geometric accuracy estimated over supersite paths/rows (calibration sites) with a strong constraint of cloud-free scenes, yellow bars indicate geometric accuracy estimated

over supersite paths/rows (calibration site scenes subsetting from all the L1TP scenes with no cloud constraints) using Collection 2 GCPs, and green bars indicate geometric accuracy estimated over all L1TP scenes processed in Collection 2 using Collection 2 GCPs (no cloud constraints). All results for this quarter are within the accuracy specification.

Landsat 8 Geometric Performance Summary 27

0.0035

Yaw

0.003

Yaw angle, in radians

0.0025 0.002 0.0015 0.001 0.0005 0 −0.0005 Mar. 1, 2013

Mar. 1, 2014

Mar. 1, 2015

Mar. 1, 2016

Mar. 1, 2017

Mar. 1, 2018

Mar. 1, 2019

Mar. 1, 2020

Mar. 1, 2021

Mar. 1, 2022

Mar. 1, 2023

Date EXPLANATION Yaw estimated from a quarterly average

Yaw in the calibration parameter file

Yaw estimated from calibration scene

Geometric accuracy

14 12 10 8 6 4 2 0

2013Q1 2013Q2 2013Q3 2013Q4 2014Q1 2014Q2 2014Q3 2014Q4 2015Q1 2015Q2 2015Q3 2015Q4 2016Q1 2016Q2 2016Q3 2016Q4 2017Q1 2017Q2 2017Q3 2017Q4 2018Q1 2018Q2 2018Q3 2018Q4 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 2020Q2 2020Q3 2020Q4 2021Q1 2021Q2 2021Q3 2021Q4 2022Q1 2022Q2 2022Q3 2022Q4 2023Q1 2023Q2 All

Circular error with 90-percent confidence, in meters

Figure 39. Landsat 8 Thermal Infrared Sensor to Operational Land Imager lifetime yaw alignment.

Calendar year and quarter (Q) EXPLANATION Calibration site—Collection 2 ground control points with strong cloud constraints Calibration site—Collection 2 ground control points with no cloud constraints All scenes—Collection 2 ground control points with no cloud constraints

Figure 40. Landsat 8 lifetime geometric accuracy by quarter.

Lifetime and quarter 2, 2023, geometric accuracies for L1TP products are 3.9 and 3.3 meters when compared against cloud-free scenes over supersite paths/rows, 5.3 and 5.0 meters when compared against all L1TP scenes

over supersite paths/rows only, and 10.4 and 11.5 meters when analyzing all the L1TP scenes processed in Collection 2, respectively. Note that seasonal effect is a factor in accuracy results.

28 ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023

Geodetic Accuracy The purpose of the geodetic accuracy assessment is to ensure that the Landsat 8 L0Rp data can be successfully processed into L1 systematic products that meet the system requirement of 65 meters at a CE90 horizontal accuracy. To measure the accuracy, calibration scenes are automatically correlated with data from the panchromatic band to measure the discrepancy between the known ground location and the position predicted by the OLI geometric model (USGS, 2021d). Based on analysis results, absolute accuracy of the Collection 2 GCPs is comparable to the DOQ supersites and is substantially better compared to the Collection 1 GCPs (Rengarajan and others, 2020). Lifetime quarterly geodetic accuracy (CE90) is shown in figure 41. Blue bars indicate the accuracy estimated using DOQ supersite paths/rows (calibration site), and green bars indicate accuracy estimated from all L1TP scenes processed in Collection 2 using Collection 2 GCPs. As in the case with the geometric accuracy, a wide variety of scene types (cloud contaminated, islands, desert, snow covered, ice sheets, and so on) are the primary contributor to the poor geodetic accuracy for Collection 2 GCP-based results. Although quarters 1, 2, and 3, 2021, indicated a slight increase in the geodetic accuracy offset, the lifetime results have been consistently well within the accuracy specification. The recent increase in the geodetic accuracy is because of a systematic bias in the along-track direction observed since

Circular error with 90-percent confidence, in meters

the November 2020 safehold events. After the bias stabilized, an update to the sensor alignment parameters in the CPF was released in quarter 4, 2021, resulting in a decrease in the observed geodetic offsets. An additional sensor alignment update was released in quarter 2, 2022, in response to an along-track offset that was greater than 10 meters and continuing to increase. Geodetic accuracy has been within 10 meters (considering both along-track and across-track directions) since then, including after the April 2023 TIRS SSM excursion anomaly, and no sensor alignment update was necessary. Lifetime geodetic accuracies for systematic products are 16.9 meters when compared using DOQ GCPs over supersites and 25.9 meters when compared using Collection 2 GCPs over all the scenes processed in Collection 2, respectively.

Landsat 8 to Sentinel-2 Registration Accuracy The USGS Landsat Collection 2 release included an update to the Landsat ground reference dataset by harmonizing with the Sentinel-2 Global Reference Image (GRI) dataset. The objective of using the GRI dataset in Landsat ground reference was to improve the absolute and relative accuracies of the Landsat products across all missions and to improve the coregistration between Landsat and Sentinel-2 terraincorrected products. The Cal/Val Team plans to continue to assess the coregistration error between the two sensors over a select number of sites that are globally distributed.

Geodetic accuracy

40 35 30 25 20 15 10 5

Calendar year and quarter (Q) EXPLANATION Calibration site—Digital orthophoto quadrangle ground control points All scenes—Collection 2 ground control points

Figure 41. Landsat 8 lifetime geodetic accuracy by quarter.

Landsat 7 Radiometric Performance Summary 29 The European Space Agency began using GRI as reference in their Sentinel-2 Level-1C (L1C) processing in March/ April 2021, but global coverage (excluding Antarctica and small islands) was limited to scenes over Europe and Africa until August 2021. Sentinel-2 L1C products generated before GRI availability are planned to be reprocessed with GRI as a ground reference at a future date. The observed coregistration error between Landsat 8 L1TP products and Sentinel-2 L1C products without the use of GRI (as indicated with the magenta dots) is shown in figure 42, as well as coregistration errors with Sentinel-2 L1C products where GRI was used (as indicated with the yellow dots). Coregistration errors without the use of GRI are expected to be less than 15 meters; coregistration errors with GRI are expected to be less than 8 meters. For reference, observed coregistration errors between Landsat 8 L1TP products also are included in the figure as indicated with the orange dots. With global availability of Sentinel-2 L1C products using GRI as the geospatial reference, the number of characterized sites has been expanded to a couple of tiles from each continent while also using the growing temporal inventory. Based on analysis results, continent specific GRI differences have not been observed.

Landsat 7 Radiometric Performance Summary Onboard Calibrator Trends The ETM+ has three onboard calibration devices: the Internal Calibrator, the Partial Aperture Solar Calibrator, and the Full Aperture Solar Calibrator. These calibration devices have been used to monitor radiometric stability since launch (April 15, 1999; Markham and others, 1994; Barsi and others, 2016; USGS, 2019a). The responsivity of the ETM+ as determined from the onboard calibrators is shown in figure 43 for the blue band and figure 44 for the SWIR 1 band. The three calibrators all indicate degradation over time, although at varying rates that changed at different times. The degradation shown here is thought to be primarily within the calibrators and not because of the ETM+ detectors or electronics (Markham and others, 2012). Furthermore, preliminary analyses indicate no substantial change in response after a series of orbitlowering maneuvers, beginning on April 6, 2022. Additional information about the Landsat 7 orbit lowering is available at https://www.usgs.gov/centers/eros/news/landsat-7- lowered-standard-landsat-orbit#:~:text=The%20satellite's %20primary%20science%20mission%20has%20ended&text= On%20April%206%2C%202022%2C%20the,satellite's%20 orbit%20by%208%20kilometers.

Registration error as radial root mean square

20 18 16 14 12 10 8 6 4 2 0 Feb. 13, 2021

May 24, 2021

Sept. 1, 2021

Dec. 10, 2021

Mar. 20, 2022

June 28, 2022

Oct. 6, 2022

Jan. 14, 2023

Apr. 24, 2023

EXPLANATION Landsat 8 versus Landsat 8 Landsat 8 versus Sentinel-2—Using global reference image Landsat 8 versus Sentinel-2—Without using global reference image

Figure 42. Landsat 8 coregistration error between the Level 1 terrain-corrected product and Sentinel-2 Level 1 orthorectified product since quarter 1, 2021.

30 ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023 Blue 1.3 1.2

Gain

1.1 1.0 0.9 0.8 0.7 0

Years since launch (April 15, 1999) EXPLANATION Gain model

Gain—Calculated as the digital number per watt per square meter per steradian per micrometer (W/m2 sr µm) Full Aperture Solar Calibrator Internal Calibrator—High and low redundant

Prelaunch gain with error bars measured during prelaunch testing

Internal Calibrator—High and low primary

Figure 43. Landsat 7 Enhanced Thematic Mapper Plus blue band lifetime gains. Shortwave infrared 1 9.5 9

Gain

8.5 8 7.5 7 6.5 6 0

Years since launch (April 15, 1999) EXPLANATION Gain model

Gain—Calculated as the digital number per watt per square meter per steradian per micrometer (W/m2 sr µm) Full Aperture Solar Calibrator Internal Calibrator—High and low redundant Internal Calibrator—High and low primary

Prelaunch gain with error bars measured during prelaunch testing

Figure 44. Landsat 7 Enhanced Thematic Mapper Plus shortwave infrared 1 band lifetime gains.

Landsat 7 Radiometric Performance Summary 31 D’Etudes Spatiales (CNES) were used to develop a new gain model for ETM+, which was applied starting in 2013 (USGS, 2021c). The Cal/Val Team uses multiple PICS for monitoring radiometric changes because of the temporal stability of those sites (Tuli and others, 2019). PICS trending calculates basic statistics from geographic regions of interest (ROIs) extracted from geometrically corrected Landsat products. The primary purpose for trending is to repeatedly characterize PICS, save results to the database, and thus enable an automatic monitoring of ETM+ temporal stability. The lifetime top of atmosphere reflectance values observed over the Libya 4 PICS site (lat 28.55° N., long 23.39° E.) using the CNES ROI are shown in figure 46. The lifetime temporal trends show seasonal effects, which are more substantial in the higher wavelength SWIR bands. After removal of the seasonal effect, there is a slight indication of deviation from current trends; the deviation is in the negative direction for the blue, green, red, and SWIR 2 bands and in the positive direction for the near infrared, SWIR 1, and panchromatic bands. Recent trends indicate deviation in the negative direction in all bands except the blue and green bands, possibly as a result of the orbit lowering.

Coherent Noise Coherent noise in the ETM+ has been monitored since launch using a fast Fourier transform on dark nighttime data (Barsi and others, 2016). The Landsat 7 lifetime coherent noise results for specific band and detector combinations at designated frequencies are shown in figure 45. Magnitudes of most coherent noise components remain low, but a positive trend in coherent noise power of SWIR 1 (band 5) detector 12 (orange circles) has been observed. In this SWIR 1 detector 12 case, noise power decreases with instrument ontime along an interval, so scenes acquired earlier in an interval are subject to stronger coherent noise features. In 2010, only the first few scenes acquired in an interval were affected by the coherent noise, but by 2015, the noise was strong enough that it was still present as many as 15 minutes later (fig. 45).

Pseudoinvariant Calibration Sites Trending PICS also are used to monitor the ETM+ radiometric stability. Several of the PICS regions (Committee on Earth Observation Satellites, 2021) defined by Centre National

0.3

12 10

Coherent noise

9 0.2

8 7 6 5

0.1

4 3 2

Date EXPLANATION Coherent noise at the designated frequency (in kilohertz [kHz])—Coherent noise is calculated as the digital number squared 4.9 kHz—Red band, detector 11 4.9 kHz—Panchromatic band, detector 12 20 kHz—Blue band, detector 9 104 kHz—Panchromatic band, detector 3

4.9 kHz—Green band, detector 13 5.64 kHz—Red band, detector 4 20 kHz—Panchromatic band, detector 5 About 16 kHz—Shortwave infrared 1 band, detector 12

Figure 45. Landsat 7 Enhanced Thematic Mapper Plus lifetime coherent noise.

Sept. 2022

Sept. 2021

Sept. 2020

Sept. 2019

Sept. 2018

Sept. 2017

Sept. 2016

Sept. 2015

Sept. 2014

Sept. 2013

Sept. 2012

Sept. 2011

Sept. 2010

Sept. 2009

Sept. 2008

Sept. 2007

Sept. 2006

Sept. 2005

Sept. 2004

Sept. 2003

Sept. 2002

Sept. 2001

Sept. 2000

Sept. 1999

1 0

Coherent noise of the shortwave infrared 1 band, detector 12

32 ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023

0.8

Collection 2

Top of atmosphere reflectance

0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0

Years since launch (April 15, 1999) EXPLANATION Spectral band (drift per year, in percent) Blue (−0.044)

Red (−0.026)

Shortwave infrared 1 (0.013)

Green (−0.032)

Near infrared (0.020)

Shortwave infrared 2 (−0.017)

Panchromatic (0.006)

Figure 46. Libya 4 pseudoinvariant calibration site top of atmosphere reflectance trending normalizing/correcting seasonality effects, Collection 2.

Landsat 7 Geometric Performance Summary

Geodetic Accuracy

Geometric Performance Summary The Landsat 7 on-orbit geometric performance for this quarter (quarter 2, April–June 2023) meets all requirements as outlined in USGS (2019a). The quarterly results summary is provided in table 5.

The purpose of the geodetic accuracy assessment is to ensure that the Landsat 7 L0Rp data can be successfully processed into L1 systematic products that meet the system requirement of 250-meter (1σ) accuracy, excluding terrain effects and without the use of GCPs. Geodetic accuracy is monitored using calibration supersites containing GCPs

Table 5. Landsat 7 geometric performance summary, quarter 2 (April–June), 2023. [The previous quarter is quarter 1 (January–March), 2023. ETM+, Enhanced Thematic Mapper Plus; <, less than; σ, sigma; L1T, Level 1 terrain-corrected product]

Measured value from this quarter

Measured value from previous quarter1

ETM+ band registration accuracy (bands 1–5, 7)

1.9

2.0

<5.1

Meter (1σ)

ETM+ band registration accuracy (thermal [band 6])

5.8

6.0

<10.2

Meter (1σ)

Absolute geodetic accuracy

124.0

149.8

<250

Meter (1σ)

Relative geodetic accuracy

13.1

14.4

<25

Meter (1σ)

Geometric (L1T) accuracy

6.3

6.6

<12

Meter (1σ)

Requirement

1From Haque and others (2023).

Required value

Unit

Landsat 7 Geometric Performance Summary 33 derived from the DOQ aerial photography (U.S. supersites) and Satellite Pour l’Observation de la Terre (SPOT) satellite imagery (Australian supersites). The lifetime quarterly mean offsets for Landsat 7 are shown in figure 47. Within the figure, the blue bars indicate the across-track mean offset, and the green bars indicate the along-track mean offset. As of quarter 2 (April–June), 2023, this across-track offset has exceeded 93 meters, with an even greater offset of 128 meters measured in quarter 1, 2023 (Haque and others, 2023). The lifetime quarterly geodetic accuracy for Landsat 7 is shown in figure 48. The figure shows the expected geodetic accuracy of a systematic product. Magenta bars indicate the across-track root mean square error (RMSE), and light blue bars indicate the along-track RMSE. As of quarter 2, 2023, this across-track offset has exceeded 98 meters, with an even greater offset of 133 meters measured in quarter 1, 2023 (Haque and others, 2023).

Band Registration Accuracy Internal band registration measures how accurately the various Landsat 7 spectral bands are aligned to each other. The assessment provides a numerical evaluation of the accuracy of the band registration within an image using automated cross-correlation techniques between the bands to be assessed (USGS, 2021d). The per-band average RMSE since launch is shown in figure 49. Blue bars indicate band registration accuracy in the line direction, and green bars indicate band registration accuracy in the sample direction. This figure also shows the specification offsets, which each band easily outperforms.

45 30 15

Mean offset, in meters

0 −15 −30 −45 −60 −75 −90 −105

−135

1999Q3 2000Q1 2000Q3 2001Q1 2001Q3 2002Q1 2002Q3 2003Q1 2003Q3 2004Q1 2004Q3 2005Q1 2005Q3 2006Q1 2006Q3 2007Q1 2007Q3 2008Q1 2008Q3 2009Q1 2009Q3 2010Q1 2010Q3 2011Q1 2011Q3 2012Q1 2012Q3 2013Q1 2013Q3 2014Q1 2014Q3 2015Q1 2015Q3 2016Q1 2016Q3 2017Q1 2017Q3 2018Q1 2018Q3 2019Q1 2019Q3 2020Q1 2020Q3 2021Q1 2021Q3 2022Q1 2022Q3 2023Q1

−120

Calendar year and quarter (Q) EXPLANATION Mean offset Across-track mean offset Along-track mean offset

Figure 47. Landsat 7 lifetime mean offsets per quarter.

34 ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023 140

Root mean square error, in meters

120 100 80 60 40

Calendar year and quarter (Q) EXPLANATION Geodetic accuracy Across-track accuracy Along-track accuracy

Figure 48. Landsat 7 lifetime geodetic accuracy per quarter. 0.18

Offset, in instantaneous field of view

0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 1

Spectral band EXPLANATION Band registration accuracy Line direction Sample direction

Figure 49. Landsat 7 band-average root mean square registration error since launch.

Pan

Spec

Landsat 7 Geometric Performance Summary 35

Orbital Drift from Worldwide Reference System-2 Landsat 7 is nearing the end of its fuel supply. To conserve fuel, satellite inclination maneuvers have been eliminated, causing the satellite to slowly drift off the nominal WRS–2 orbit. The Cal/Val Team continues to monitor Northern and Southern Hemisphere sites to quantify the amount of WRS–2 displacement. Stakeholders use this information to determine the usability of the data. From April 6 to May 5, 2022, Landsat 7 went through several orbital maneuvers to lower the orbit by 8 kilometers, which has resulted in substantial differences in scene center easting when compared with the displacement before the orbital maneuvers. The observed orbital drift from WRS–2 for path 39, row 37 (lat 33°10′37″ N., long 115°38′05″ W.), which is a Northern Hemisphere scene, is shown in figure 50. Magenta diamonds in the figure indicate the scene center location

690

converted to easting and, for historical trending purposes, the measurements begin in 2015. The difference between extreme measurements is about 123.1 kilometers. The drift for this Northern Hemisphere scene was to the west until the orbitlowering maneuvers, after which substantial westward and eastward drift fluctuations were observed. The most recent observations from June 2023 provide further indication of westward and eastward drift fluctuations. The observed orbital drift from WRS–2 for path 100, row 73 (lat 18°47′14″ S., long 138°22′13″ E), which is a Southern Hemisphere scene, is shown in figure 51. Again, magenta diamonds indicate the scene center location converted to easting, and the figure has measurements from 2015 to the current quarter. The difference between extreme measurements is about 151.7 kilometers. The drift for this Southern Hemisphere scene was to the east until the orbitlowering maneuvers, after which substantial westward and eastward drift fluctuations were observed.

Path 39, row 37

UTM zone 11 easting, in kilometers

670 650 630 610 590 570 550 Dec. 27, 2014

May 10, 2016

Sept. 22, 2017

Feb. 4, 2019

June 18, 2020

Oct. 31, 2021

Mar. 15, 2023

Acquisition date EXPLANATION Worldwide Reference System-2 (WRS–2), path 39, row 37, Universal Transverse Mercator (UTM) zone 11 scene center easting

Figure 50. Landsat 7 lifetime orbital drift from World Reference System-2 (path 39, row 37).

36 ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023

330

Path 100, row 73

UTM zone 54 easting, in kilometers

310 290 270 250 230 210 190 170 150 Dec. 27, 2014

May 10, 2016

Sept. 22, 2017

Feb. 4, 2019

June 18, 2020

Oct. 31, 2021

Mar. 15, 2023

Acquisition date EXPLANATION Worldwide Reference System-2 (WRS–2), path 100, row 73, Universal Transverse Mercator (UTM) zone 54 scene center easting

Figure 51. Landsat 7 lifetime orbital drift from World Reference System-2 (path 100, row 73).

Quarterly Level 2 Validation Results Level 2 Surface Reflectance Pseudoinvariant Calibration Site Trending In addition to L1 products, Landsat 7 and Landsat 8 surface reflectance PICS trending is completed by the Cal/ Val Team. The primary purpose of Level 2 surface reflectance PICS trending is to repeatedly characterize the temporal stability of the ETM+ and OLI sensors. The CNES ROI has been chosen for completing the analysis. The Collection 2, Level 2 lifetime surface reflectance trends for six Landsat 7 spectral bands for the Libya 4 PICS are provided in figure 52. The x-axis represents years since launch, and the y-axis represents surface reflectance. For this analysis, cloud-free data were used. A strong seasonal effect was noted in the higher wavelength (SWIR) bands (not

shown). This seasonal effect has been reduced using appropriate linear models. After reducing seasonality from all bands, drift was estimated for each band from the slope and intercept of line fits. A small negative drift was noticeable in the blue, green, and red bands, and a positive drift was noticeable for the near infrared, SWIR 1, and SWIR 2 bands. The Collection 2, Level 2 lifetime surface reflectance trends for seven Landsat 8 spectral bands for the Libya 4 PICS are provided in figure 53. Drift estimate results indicate small decay in responsivity for all bands. The x-axis represents years since launch, and the y-axis represents surface reflectance. The seasonal effect has been reduced from all bands using appropriate models. Overall, OLI and ETM+ indicated stability for Level 2 surface reflectance based on the analysis completed. No substantial instability was monitored in any band, according to the lifetime drift estimate results.

Quarterly Level 2 Validation Results 37 Enhanced Thematic Mapper Plus, Collection 2

0.8 0.7

Surface reflectance

0.6 0.5 0.4 0.3 0.2 0.1 0 0

Years since launch (April 15, 1999) EXPLANATION Spectral band (drift per year, in percent) Blue (−0.065)

Red (−0.004)

Shortwave infrared 1 (0.031)

Green (−0.006)

Near infrared (0.051)

Shortwave infrared 2 (0.027)

Figure 52. Libya 4 pseudoinvariant calibration site surface reflectance trending, Landsat 7 Enhanced Thematic Mapper Plus, Collection 2.

0.8

Operational Land Imager, Collection 2

0.7

Surface reflectance

0.6 0.5 0.4 0.3 0.2 0.1 0 0

Years since launch (February 11, 2013) EXPLANATION Spectral band (drift per year, in percent) Blue (−0.059)

Red (−0.053)

Shortwave infrared 1 (−0.064)

Green (−0.078)

Near infrared (−0.063)

Shortwave infrared 2 (−0.060)

Coastal/aerosol (−0.027)

Figure 53. Libya 4 pseudoinvariant calibration site surface reflectance trending, Landsat 8 Operational Land Imager, Collection 2.

38 ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023

Summary The Landsat 8 Operational Land Imager and Thermal Infrared Sensor on-orbit radiometric and geometric performance for quarter 2 (April–June), 2023, meets all requirements. Landsat 7 Enhanced Thematic Mapper Plus (ETM+) on-orbit geometric performance for this reporting quarter meets all requirements. Although not measured against specified requirements, Landsat 7 ETM+ on-orbit radiometric performance was fully characterized and summarized in this report. Additionally, quarterly Level 2 validation results for Operational Land Imager and ETM+ indicated stability for Level 2 surface reflectance.

References Cited Barsi, J.A., Markham, B.L., Czapla-Myers, J.S., Helder, D.L., Hook, S.J., Schott, J.R., and Haque, M.O., 2016, Landsat-7 ETM+ radiometric calibration status: Proceedings of SPIE Optical Engineering + Applications, San Diego, Calif., 2016, Earth Observing Systems XXI, v. 9972, accessed July 2023 at https://doi.org/10.1117/12.2238625. Committee on Earth Observation Satellites, 2021, PICS— Pseudo-Invariant Calibration Sites: Committee on Earth Observation Satellites, Cal/Val Portal website, accessed July 2023 at https://calvalportal.ceos.org/pics_sites. Executive Office of the President of the United States, 2007, A plan for a U.S. National Land Imaging Program—Future of Land Imaging Interagency Working Group: Washington, D.C., Executive Office of the President of the United States, National Science and Technology Council (NSTC) Office of Science and Technology Policy (OSTP) report, 110 p., accessed July 2023 at https://obamawhitehouse.arc hives.gov/sites/default/files/microsites/ostp/fli_iwg_report_ print_ready_low_res.pdf. Executive Office of the President of the United States, 2014, National plan for Civil Earth Observations: Washington, D.C., Executive Office of the President of the United States, Office of Science and Technology Policy (OSTP) report, 62 p., accessed July 2023 at https://obamawhitehouse.arc hives.gov/sites/default/files/microsites/ostp/NSTC/2014_ national_plan_for_civil_earth_observations.pdf. Executive Office of the President of the United States, 2016, The second national Civil Earth Observation assessment— Societal benefit areas, subareas, and key objectives: Washington, D.C., Executive Office of the President of the United States, Office of Science and Technology Policy (OSTP) report, 21 p., accessed July 2023 at https:/ /obamawhitehouse.archives.gov/sites/default/files/ microsites/ostp/NSTC/the_second_national_civil_earth_ observations_assessment.pdf.

Haque, M.O., Rengarajan, R., Lubke, M., Hasan, M.N., Shrestha, A., Tuli, F.T., Shaw, J.L., Denevan, A., Franks, S., Micijevic, E., Choate, M.J., Anderson, C., Thome, K., Kaita, E., Barsi, J., Levy, R., and Miller, J., 2023, ECCOE Landsat quarterly Calibration and Validation report— Quarter 1, 2023: U.S. Geological Survey Open-File Report 2023–1050, 39 p., accessed July 2023 at https://doi.org/ 10.3133/ofr20231050. Haque, M.O., Rengarajan, R., Lubke, M., Tuli, F.T.Z., Shaw, J.L., Hasan, M.N., Denevan, A., Franks, S., Micijevic, E., Choate, M.J., Anderson, C., Markham, B., Thome, K., Kaita, E., Barsi, J., Levy, R., and Ong, L., 2022, ECCOE Landsat Quarterly Calibration and Validation report— Quarter 4, 2021: U.S. Geological Survey Open-File Report 2022–1033, 38 p., accessed July 2023 at https://doi.org/ 10.3133/ofr20221033. Markham, B.L., Ahmad, S.P., Irons, J.R., and Williams, D.L., 1994, Radiometric calibration of the Landsat-7 Enhanced Thematic Mapper Plus: Proceedings of IGARSS ‘94—1994 IEEE International Geoscience and Remote Sensing Symposium, 1994, v. 4, p. 2004–2006, accessed July 2023 at https://doi.org/10.1109/IGARSS.1994.399636. Markham, B.L., Haque, M.O., Barsi, J.A., Micijevic, E., Helder, D.L., Thome, K.J., Aaron, D., and Czapla-Myers, J.S., 2012, Landsat-7 ETM+—12 years on-orbit reflectiveband radiometric performance: IEEE Transactions on Geoscience and Remote Sensing, v. 50, no. 5, p. 2056–2062, accessed July 2023 at https://doi.org/10.1109/ TGRS.2011.2169803. Micijevic, E., Rengarajan, R., Haque, M.O., Lubke, M., Tuli, F.T., Shaw, J.L., Hasan, N., Denevan, A., Franks, S., Choate, M.J., Anderson, C., Markham, B., Thome, K., Kaita, E., Barsi, J., Levy, R., and Ong, L., 2021, ECCOE Landsat quarterly Calibration and Validation report— Quarter 2, 2021: U.S. Geological Survey Open-File Report 2021–1105, 40 p., accessed July 2023 at https://doi.org/ 10.3133/ofr20211105. Montanaro, M., Barsi, J.A., Lunsford, A., Rohrbach, S., and Markham, B.L., 2014, Performance of the Thermal Infrared Sensor on-board Landsat 8 over the first year on-orbit: Proceedings of SPIE Optical Engineering + Applications, San Diego, Calif., 2014, Earth Observing Systems XIX, v. 9218, 14 p., accessed July 2023 at https://doi.org/10.1117/ 12.2063457. National Geospatial Advisory Committee, 2020, Landsat data—Community standard for data calibration (October 2020): Landsat Advisory Group, 12 p., accessed July 2023 at https://www.fgdc.gov/ngac/meetings/october- 2020/ngac-paper-landsat-data-community-standard-for.pdf.

References Cited 39 Rengarajan, R., Storey, J.C., and Choate, M.J., 2020, Harmonizing the Landsat ground reference with the Sentinel-2 Global Reference image using space-based bundle adjustment: Remote Sensing, v. 12, no. 19, article 3132, 26 p., accessed July 2023 at https://doi.org/10.3390/ rs12193132. Tuli, F.T.Z., Pinto, C.T., Angal, A., Xiong, X., and Helder, D., 2019, New approach for temporal stability evaluation of Pseudo-Invariant Calibration Sites (PICS): Remote Sensing, v. 11, no. 12, article 1502, 23 p., accessed July 2023 at https://doi.org/10.3390/rs11121502. U.S. Geological Survey [USGS], 2019a, Landsat 7 (L7) data users handbook (ver. 2.0, November 2019): U.S. Geological Survey, Earth Resources Observation and Science (EROS) Center, LSDS–1927, 139 p., accessed July 2023 at h ttps://www.usgs.gov/landsat-missions/landsat-7-data-users- handbook. U.S. Geological Survey [USGS], 2019b, Landsat 8 (L8) data users handbook (ver. 5.0, November 2019): U.S. Geological Survey, Earth Resources Observation and Science (EROS) Center, LSDS–1574, 106 p., accessed July 2023 at h ttps://www.usgs.gov/landsat-missions/landsat-8-data-users- handbook. U.S. Geological Survey [USGS], 2020a, Landsat 8–9 Operational Land Imager (OLI)—Thermal Infrared Sensor (TIRS) Collection 2 Level 1 (L1) data format control book (DFCB) (ver. 6.0, September 2020): U.S. Geological Survey, Earth Resources Observation and Science (EROS) Center, LSDS–1822, 58 p., accessed July 2023 at https://www.usgs.gov/media/files/landsat-8-9-olitirs- collection-2-level-1-data-format-control-book.

U.S. Geological Survey [USGS], 2020b, Landsat 8–9 Operational Land Imager (OLI)—Thermal Infrared Sensor (TIRS) Collection 2 Level 2 (L2) data format control book (DFCB) (ver. 6.0, September 2020): U.S. Geological Survey, Earth Resources Observation and Science (EROS) Center, LSDS–1328, 72 p., accessed July 2023 at https://www.usgs.gov/media/files/landsat-8-9-olitirs- collection-2-level-2-data-format-control-book. U.S. Geological Survey [USGS], 2021a, EarthExplorer: U.S. Geological Survey database, accessed July 2023 at https://ea rthexplorer.usgs.gov. U.S. Geological Survey [USGS], 2021b, EROS Cal/Val Center of Excellence (ECCOE): U.S. Geological Survey website, accessed July 2023 at https://www.usgs.gov/calval. U.S. Geological Survey [USGS], 2021c, Landsat 7 ETM+ calibration notices: U.S. Geological Survey website, accessed July 2023 at https://www.usgs.gov/landsat-missions/landsat- 7-etm-calibration-notices. U.S. Geological Survey [USGS], 2021d, Landsat 8–9 Calibration and Validation (Cal/Val) algorithm description document (ADD) (ver. 4.0, January 2021): U.S. Geological Survey, Earth Resources Observation and Science (EROS) Center, LSDS–1747, 807 p., accessed July 2023 at h ttps://www.usgs.gov/media/files/landsat-8-9-calibration- validation-algorithm-description-document.

For more information about this publication, contact: Director, USGS Earth Resources Observation and Science Center 47914 252nd Street Sioux Falls, SD 57198 605–594–6151 For additional information, visit: https://www.usgs.gov/centers/eros Publishing support provided by the Rolla Publishing Service Center

Haque and others—ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023—OFR 2023–1075

ISSN 2331-1258 (online) https://doi.org/10.3133/ofr20231075

ECCOE Landsat Quarterly Calibration and Validation Report—Quarter 2, 2023

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