Landsat 9 OLI and TIRS Calibration Notices
This page displays the Landsat 9 Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) instrument calibration notices.
April 2026 - Landsat 9 Data Held During October 2025 Safehold Processed
Landsat 9 data acquired following an October 2025 safehold event were recently processed into Landsat Level-1 and Level-2 products. Additionally, a small number of Landsat products processed just prior and just after the safehold were also reprocessed.
In October 2025, Landsat 9’s sensors—the Operational Land Imager and Thermal Infrared Sensor—did not acquire data from midday October 17 (DOY 290) to midday October 22 (DOY 295) due to the spacecraft entering a safehold.
After the safehold ended, imaging resumed. The data acquired between 11:47 a.m. CDT on October 22 to 2:43 p.m. CDT on October 24 were held and not processed into products so the USGS-NASA Calibration/Validation Team could verify the data’s integrity.
Following their analysis, the team applied updated radiometric and geometric calibration coefficients to the data and generated 1,585 new Level-1 products, which are now available for download. The follow-on generation of Landsat Level-2, Landsat U.S. Analysis Ready Data (ARD), and Level-3 science products are in process.
In addition to the newly processed products, 42 Level-1 products from October 17, and 13 products from October 24, were reprocessed with updated radiometric correction parameters. Newly generated Level-1 and Level-2 products have replaced those already visible on EarthExplorer (EE) and other USGS data access sources. Landsat U.S. Analysis Ready Data (ARD) and Level-3 products will also be regenerated in the near future.
Access the April 6, 2026 News webpage describing this processing reprocessing effort.
February 1, 2026 – Landsat 9 Post-SADA Anomaly OLI and TIRS Calibration Updates
Following the October 17, 2025, Solar Array Drive Assembly (SADA) safehold event, the Landsat 9 Cal/Val team completed a full radiometric assessment of both Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS). Although the instruments were successfully restored, the first post recovery solar diffuser and blackbody data showed small but consistent shifts in detector level behavior.
To maintain accurate radiometric performance, two new Calibration Parameter Files (CPFs) were released on October 29, 2025. The second of these CPFs included all necessary post anomaly calibration updates, specifically targeting relative gains and Sensor Chip Assembly (SCA) level gain corrections for both instruments.
For OLI, the safehold caused slight but measurable shifts in detector responses across multiple bands — well within typical quarterly drift ranges but still large enough to require formal calibration updates. As a result, both OLI relative gains and SCA level relative gains were refreshed to eliminate striping artifacts and restore proper bias/gain behavior in Level 1 products. TIRS was largely stable after the anomaly, showing only minor changes in blackbody and deep space responses, but several detectors exhibited small gain drifts. To preserve long-term trending continuity and thermal product uniformity, TIRS relative gains and SCA level gains were also updated in the CPF.
Band average gains for both OLI and TIRS were reviewed but not modified. Early post-event diffuser and lamp data provided indication, but not enough evidence to justify an immediate adjustment of OLI’s band average calibration parameters, and TIRS showed no meaningful band level shifts requiring adjustment. Overall, the targeted CPF updates restored proper radiometric behavior after the anomaly, prevented detector level artifacts from propagating into science products, and ensured consistent calibration going forward.
July 25, 2025 – Landsat 9 TIRS Band-Average Absolute Gain and Algorithm Updates
Major updates to Landsat 9’s Thermal Infrared Sensor (TIRS) calibration were made during the Quarter 3 (July-September) 2025 Calibration Parameter File (CPF) update. Significant refinements were made to the relative gain (RG) modeling, detector level and SCA level relative gains were updated, and the relative gain prediction algorithm was revised to match the methodology used for Landsat 8 - this change improves the long-term prediction of detector drift, addresses continued slow degradations observed since the 2022 Cryocooler Electronics (CCE) reset, and better manages occasional “jumper” detectors that show sudden gain shifts. By aligning the algorithm across missions, the update reduces banding and striping artifacts and strengthens cross sensor radiometric consistency within the Landsat constellation.
The TIRS band average absolute gain was also updated in Q3 2025. Analysis showed a gradual decreasing trend in overall TIRS responsivity following the March 2022 CCE reset, affecting both Bands 10 and 11. While previous updates focused on individual detector behavior, the accumulated long-term drift made it necessary to adjust the overall band level radiance scale. The updated band average gain was computed using a degradation fit model that evaluates long-term detector trends and applies a unified correction of ~0.35% for Band 10 and ~0.55% for Band 11, ensuring that thermal radiance products remain stable and accurately reflect the true instrument response.
Together, these updates represent a major milestone in maintaining TIRS calibration quality. The revised relative gain algorithm improves temporal modeling and detector uniformity, while the new band average absolute gain correction restores the mission’s thermal radiance scale. These changes ensure that Landsat 9 continues to deliver consistent, artifact-free thermal products and remains well aligned with Landsat 8 and vicarious calibration datasets.
July 1, 2024 – Landsat 9 Coastal/Aerosol Band Absolute Gain and TIRS Detector Swap
The Quarter 3 (July-September) 2024 Landsat 9 Calibration Parameter File (CPF) update includes updates for the Operational Land Imager (OLI) Coastal/Aerosol band absolute gain to correct for slight lifetime degradation and a detector swap in the Thermal Infrared Sensor (TIRS) Band 10 Detector 474, located on Sensor Chip Assembly (SCA) 2.
Degradation of the primary detector required a swap to the secondary detector. The Response Linearization Look-Up Table (RLUT) was also updated to account for the detector swap.
August 13, 2023 – Landsat 9 TIRS Band 11 Detector Swap
During the Landsat 9 reprocessing effort and the Quarter 3 (July-September) 2023 calibration cycle, several Landsat 9 Thermal Infrared Sensor (TIRS) detectors were found to exhibit degraded performance and were replaced with their redundant counterparts. For Band 11, three primary detectors — 697, 1173, and 1746 — were swapped out due to declining responsivity. Additionally, Detector 892 on SCA 2 showed persistent instability in its relative gain behavior and was replaced with its redundant detector, which demonstrated stable response and appropriate noise characteristics. These changes were made to maintain detector level integrity and ensure high quality thermal data across the mission.
To support these detector swaps, the Quarter 3 (July-September) 2023 Calibration Parameter File (CPF) included updates across several calibration groups. Adjustments were applied to detector response tables, relative gains, SCA level gains, detector offsets, detector status mappings, and supporting timing and attitude parameters. The Radiometric Look-Up Tables (RLUTs) were also revised to ensure that the new detector configuration would be handled correctly throughout radiometric processing. These updates ensured that downstream Level 1 products accurately reflected the revised focal plane layout.
With these changes in place, the newly activated Band 11 SCA 2 redundant detector became fully calibrated within the operational processing system. The updated CPF ensured that detector level behavior, gain patterns, and offsets were accurately represented in all scenes following the swap. As a result, radiometric consistency was restored and maintained, preventing further degradation in product quality that would have stemmed from the previously unstable primary detector.
March 20, 2023 – Landsat 9 TIRS SCA-C Anomaly
On February 27, 2023, Landsat 9 experienced a Thermal Infrared Sensor (TIRS) Sensor Chip Assembly C (SCA-C) anomaly in which voltages and currents on the affected electronics dropped to near zero, causing the middle third of the focal plane to produce blank imagery. The instrument was successfully restored through a sequence of recovery actions that included a Focal Plane Electronics (FPE) reset, reinitialization, and full focal plane powerup. After recovery, the Cal/Val Team performed detailed radiometric and geometric evaluations to determine whether the event required changes to the Calibration Parameter File (CPF).
Radiometric analysis showed that overall responsivity for Bands 10 and 11 remained stable and consistent with pre-event performance (fig. 1). Only one detector exhibited an abnormal change, but it was already scheduled for replacement as part of an upcoming reprocessing campaign, so no CPF adjustments were made. Geometric checks also showed no measurable impacts: band-to-band registration remained unchanged, and geodetic accuracy evaluations confirmed that along-track and across-track performance stayed within normal behavior.
Because neither radiometric nor geometric evaluations revealed system level changes, no CPF updates were required in response to the SCA-C anomaly. Forward processing continued using the existing CPF, and the event did not alter plans for the broader reprocessing campaign. The anomaly was fully resolved through instrument recovery procedures, with no lasting impact on data quality for users.
March 1, 2023 - Landsat 9 Reprocessing Event
February 23, 2023 Landsat Missions News announcement
The USGS Landsat Project will begin reprocessing of the Landsat 9 Collection 2 Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) data from the first year of operations beginning March 1, 2023, to take advantage of calibration updates identified by the USGS/NASA Calibration and Validation team. The original image data will be replaced in the archive with the reprocessed imagery. Reprocessing is expected to take approximately 6-8 weeks.
Listed below are the updates being applied to the data and potential impacts these changes may have on use of the data. Users are encouraged to assess these improvements and impacts against their science work and applications to determine if their Landsat 9 data should be replaced with the updated data. Please note, the Product ID contains the most recent processing date and that will facilitate identification of scenes included in this reprocessing effort. All reprocessed imagery will have a processing date that is March 1, 2023 or later.
Calibration Updates Affecting OLI
OLI Sensor Chip Assembly (SCA) Relative Gains (Banding)
This update reduces the visible banding between the 14 focal plane modules in the SWIR-2 spectral band (Band 7) of Landsat 9's OLI over bright targets (Figure 1). This banding was corrected in imagery processed after March 8, 2022, and this current reprocessing effort will correct the remaining imagery processed prior to March 8, 2022.
OLI Cross-Calibration (Reflectance and Radiance)
Cross-calibration between the OLI sensors on Landsat 9 and Landsat 8 was performed using data collected during the November 2021 underfly activity. After the initial cross-calibration during Landsat 9 commissioning, the analysis was refined during the first year of operations, and updated calibration parameters improve the consistency of Landsat 8 and Landsat 9. This update provides a modest correction to all Landsat 9 OLI bands, with largest improvements of ~0.5 percent in Green spectral band (Band 3) reflectance and ~5 percent in Cirrus spectral band (Band 9) radiance (Table 1).
| Band | Reflectance Mean | Radiance Mean |
|---|---|---|
| Band 1 | 1.001 | 0.999 |
| Band 2 | 1.002 | 1.000 |
| Band 3 | 0.996 | 0.9978 |
| Band 4 | 1.000 | 0.996 |
| Band 5 | 1.001 | 0.996 |
| Band 6 | 1.003 | 0.9923 |
| Band 7 | 1.002 | 0.990 |
| Band 8 | 0.999 | 0.9962 |
| Band 9 | 1.0077 | 0.945 |
Calibration Updates Affecting TIRS
TIRS Absolute Bias (Radiance)
Updates were made to TIRS absolute radiance, which affects top of atmosphere, brightness temperature, and surface temperature. Throughout the first year of Landsat 9 operations, comparisons between Landsat 9 products and NASA JPL and NOAA buoy-data showed the need to update absolute thermal calibration (Figure 2). This update ties Landsat 9 calibration to the same reference as Landsat 8. Prior to this update Landsat 9 absolute thermal calibration was tied to pre-launch laboratory measurements. The amount of effect is variable across different measured temperatures: Figure 3 shows the impact in Kelvin at various temperatures.
TIRS Detector Swaps/Relative Gains (Striping)
Sixteen detectors in Band 10 and three detectors in Band 11 were replaced with their redundant detectors to reduce striping due to changes in responsivity. The resulting stripes could appear at any time and could not be adequately corrected for with quarterly calibration updates. The detector swap will result in more stable detectors being used to generate the Level-1 and Level-2 image products and should result in a lower level of striping across Bands 10 and 11.
Improvements to Systematic Terrain (L1GT) scenes
An along track alignment adjustment of the OLI instrument improves L1GT accuracy by up to 20 meters. Although all L1GT products benefit, the greatest improvement is observed in areas where L1GT are the only products ever created (i.e., in areas where little or no ground control exits). (Figure 5, Table 2). All scenes over Antarctica will be improved, along with several islands, Greenland, and coastal images made up largely of water. Figure 6 shows an example of the improvement.
| Path/Row Type | Description | Number of L1GT Scenes |
|---|---|---|
| Antarctica | WRS Rows 101 to 133 | 32,930 |
| Greenland | 100% Land, Rows 2-15 | 2,081 |
| Island/Coastal Sliver | Between 0.001% to 0.94% Land | 583 |
| Open Ocean | 0% Land, Rows 1-100, 247-248 | 8,204 |
| Night/Ascending | No Percent Land Available | 6,148 |
The magnitude of the change associated with the Sensor Alignment calibration can be seen in the Geodetic Accuracy pre-fit means results where the term pre-fit refers the measured offset between the reference imagery and the Landsat product prior to ground control being applied to the imagery. These results are shown in Figure 7 where each geometric calibration site is shown along with a moving average (MA) of that data to better demonstrate the changes over time that is occurring with respect to the sensor alignment parameters.
TIRS to OLI Alignment
Adjustment will improve TIRS to OLI co-instrument alignment for all scenes in the archive (Figure 8).
Science and Application User Impacts
A select number of Landsat 9 scenes were selected to quantify the impact of calibration updates on Landsat 9 Level-2 products. This included 25 globally distributed scenes to capture extreme atmospheric conditions and different land cover types and a stack of 22 scenes over Path39/Row37 (Southwestern United States) for time series analysis. Figure 9 shows the geographic distribution of the Landsat 9 scenes used for impact assessment.
The overall impact of calibration updates on the atmospherically compensated Level-2 Surface Reflectance and Surface Temperature products is minor. The magnitude of the change in Level-2 products is within the uncertainty range of atmospheric correction algorithms. The enhancements in Visible to Short Wave Infrared (VSWIR) banding and Thermal Infrared (TIR) striping artifacts described for the Level-1 also apply for the Level-2 science products. The following sections provide a more detailed description of the change in Level-2 Surface Reflectance and Surface Temperature products.
Summary of VSWIR Bands Changes
The change in Level-2 Surface Reflectance for the VSWIR spectral bands was minimal and well-correlated with the Level-1 Top of Atmosphere (TOA) reflectance changes. Figure 10 summarizes the Mean Absolute Difference (MAD) for the Level-1 TOA (grey bars) Reflectance and Level-2 Surface Reflectance (yellow bars). As expected, the operational Land Surface Reflectance Code (LaSRC) algorithm used for atmospheric correction introduces larger differences in the Level-2 Surface Reflectance product compared to Level-1. On average, the Green spectral band (Band 3) shows largest Surface Reflectance difference (0.0013) followed by the SWIR1 (0.0010) and SWIR2 (0.0009). The Level-1 TOA Reflectance change was minimum for the Cirrus spectral band (8.2e-5 units of reflectance; Band 9).
Figure 11 shows the relative change in TOA and Surface Reflectance using the Mean Absolute Percent Difference (MAPD) statistic. Due to its low dynamic range, the small reflectance changes in the Cirrus band (8.2e-5)(Band 9) can translate to relatively large (~1.1 percent) MAPD in Level-1 TOA Reflectance.
Relative change in Level-2 Surface Reflectance is mainly controlled by the approximation of aerosol path radiance. The Aerosol Optical Thickness (AOT) in the operational LaSRC algorithm is estimated using the ratio between the Red (Band 4), Blue (Band 2), and Coastal Aerosol (Band 1) spectral bands. The path radiance decreases with wavelength. Therefore, shorter wavelengths are expected to be relatively more sensitive to any Level-1 radiometric variation. The Coastal Aerosol spectral band has highest relative sensitivity (MAPD of 4.6 percent) in Level-2 Surface Reflectance among the VSWIR spectral bands.
As indicated in cross-calibration table (Table 1), most VSWIR spectral bands are expected to show slightly brighter reflectance values on average after applying the calibration updates. The Mean Difference in Figure 12 below illustrates a slight increase in reflectance of most VSWIR spectral bands. The Green spectral band (Band 3) will be slightly darker (decreased reflectance), while the Red spectral band (Band 4) is almost unchanged on average.
The left panel in Figure 13 shows the Surface Reflectance difference for SWIR2 (Band 7) as a result of calibration updates. The SCA bandings in the difference image are due to enhancements in the relative gain. The scatterplot on the right panel shows the strong overall agreement between the Surface Reflectance before and after the reprocessing.
Figure 14 shows an example of on-demand Level-2 Aquatic Reflectance Band 1 (Coastal Aerosol) generated for a pair of scenes acquired during the Landsat 8/Landsat 9 underfly in November 2021. The reprocessed Landsat 9 image (right image) reveals less SCA Banding compared to the original image (middle).
Summary of Thermal Band Changes
The overall impact of the calibration updates on the TOA Brightness Temperature at Band 10 and the Level-2 Single Channel Surface Temperature product calculated using this band is negligible. Figure 15 shows that the Mean Absolute Difference for ST Band 10 is 0.06 Kelvin for the test scenes. This is well within the range of Level-2 Surface Temperature uncertainty.
TIRS Band 11 is expected to change more significantly compared to Band 10. The Mean Absolute Difference for the Top of Atmosphere Brightness Temperature at Band 11 is ~0.37 Kelvin for the studied scenes. The boxplot of difference in Figure 16 illustrates that all studies scenes will have a greater Brightness Temperature after applying the calibration updates.
Figure 17 shows an example of a Level-2 Surface Temperature product generated by applying the single channel algorithm on Band 10. The striping artifacts over the water body are clearly improved after applying the calibration updates.
Changes in Quality Assessment Layer
The impact on Pixel Quality Assessment (QA_PIXEL) generated using the C Function of Mask (CFMask) algorithm is very minor. The total difference in QA_PIXEL is less than 3.0 percent for the studied scenes. This difference is less than 0.3 percent and 0.5 percent for the Cirrus and Snow bits, respectively.
June 20-21, 2022 - Moon affects Landsat 9 thermal data
The Landsat Calibration and Validation Team identified 130 Landsat 9 scenes acquired from June 20-21, 2022, over a period of nine hours, that were affected with the presence of the Moon in the data. The presence of the Moon in deep space data causes errors in estimation of background response of the affected detectors, which leads to creation of dark streaks in thermal imagery. Landsat 9 Operational Land Imager (OLI) bands are not impacted.
Visit the July 6, 2022 Landsat Missions News for more details.
March 22-24, 2022 - Moon affects Landsat 9 thermal data
The USGS/NASA Landsat Flight Operations and Landsat Calibration and Validation Team have identified a number of Landsat 9 calibration intervals acquired from March 22-24, 2022, that were affected with the presence of the Moon in the data.
This caused an over-estimation of bias of affected detectors, resulting in darker streaks in Landsat 9 TIRS image data (see example image below). Landsat 9 OLI bands were not affected. This issue impacted 942 Landsat 9 Collection 2 scenes (30 hours of Earth imaging acquired between 3/22/2022 22:51 UTC and 3/24/2022 06:06 UTC).
The affected Landsat 9 scenes were reprocessed from April 6 - 7, 2022. As a result, reprocessing of the Level-1 products propagated through to all Collection 2 Level-2 products for the same period.
March 12, 2022 - Landsat 9 TIRS Cryocooler Electronics Reset
The Landsat 9 Thermal Infrared Sensor (TIRS) experienced an issue with the Cryocooler Electronics (CCE) on-board software on March 12, 2022 (DOY 071). As a result, TIRS science imaging was suspended temporarily so a software patch could be developed and applied. Following the event, a new Calibration Parameter File (CPF) and an updated Response Linearization Look Up Table (RLUT) have been created to restore the radiometric quality of TIRS post-reset imagery.
Landsat 9 scenes acquired from March 19 to present will again contain both TIRS and the Operational Land Imager (OLI) data as combined (LC09) products. Landsat 9 data acquired from March 12 – March 18 will remain available as OLI-only (LO09) products.
March 8, 2022 - Updated Calibration Parameters
The USGS and NASA Calibration/Validation team updated the Landsat 9 calibration parameters on March 8, 2022. These updates reduced banding between the 14 focal plane modules visible in the SWIR-2 band (Band 7) of Landsat 9's Operational Land Imager. The update was not applied to Landsat 9 images acquired before March 8, 2022.
NOTE: These updates do not affect the absolute calibration or cross-calibration between Landsat 9 and Landsat 8.
