This study provides a comprehensive, long-term evaluation of inter-sensor radiometric calibration biases for the NOAA OMPS Nadir and CrIS instruments using four complementary validation methodologies implemented within the Inter-Sensor Radiometric Bias Assessment (iSensor-RCBA) portal, a component of the STAR Integrated Calibration/Validation System. Overall, SDR data quality from the three OMPS Nadir instruments and three CrIS instruments aboard SNPP, NOAA-20, and NOAA-21 remains stable. The iSensor-RCBA portal has also proven to be a powerful diagnostic resource, enabling the detection of both new and previously unrecognized calibration issues and anomalies. Using the 32-day averaged difference method, we were the first to discover and identify the root cause of an inconsistency near 280 nm in inter-sensor radiometric biases between the SNPP and NOAA-20 OMPS NP instruments. The same method also revealed an unusual radiometric feature in NOAA-21 CrIS SDRs over the southern high latitudes during spring and summer. In addition, we derived decade-long degradation rates at 11 Metop-B GOME-2 wavelengths using an independent dataset—Simultaneous Nadir Overpass observations between SNPP OMPS and Metop-B GOME-2. Furthermore, iSensor-RCBA monitoring confirmed two geolocation anomalies in SNPP CrIS through a new approach involving SNO-based inter-sensor biases between GOES-16 ABI and SNPP CrIS. These cases demonstrate that iSensor-RCBA is not only a monitoring visualization tool but also a diagnostic tool that delivers unique, complementary insight into instrument performance, enabling early identification of radiometric and geolocation issues across JPSS and other satellite missions. Importantly, the analysis methods used in this study are broadly applicable to current and future missions, including JPSS-03, JPSS-04, and non-NOAA satellite systems.

This paper introduces a method of monitoring infrared channel calibration stability through direct comparison of calibrated radiances by two Advanced Baseline Imager (ABI) on two geostationary (GEO) platforms. This GEO-GEO comparison is based on radiances in the overlapping area observed by the two ABIs, pixel by pixel, at approximately the same time, location, spectrum, and viewing zenith angle. It was initially developed for GOES-17 and subsequent GOES missions to validate the ABI’s calibration around its local midnight—a subject of particular interest for instruments on three-axis stabilized geostationary satellites. With the cryocooler anomaly of the GOES-17 ABI, however, the GEO-GEO comparison became an indispensable tool to characterize GOES-17 ABI infrared (IR) channel calibration with high frequency, low uncertainty, and in near real time, providing critical feedback to root cause investigation and mitigation options. Later, the GEO-GEO comparison was applied to the GOES-18 ABI as originally intended and was proved successful. It confirms that, with few exceptions, radiometric calibration for all ABIs is stable to within 0.1 K when the radiance fluctuation is converted to the brightness temperature at 300 K.

This study presents a long-term assessment of inter-sensor radiometric calibration biases for NOAA OMPS nadir and CrIS instruments using four well-established validation methodologies implemented through the Inter-Sensor Radiometric Bias Assessment (iSensor-RCBA) portal, a component of the STAR Integrated Calibration/Validation System (ICVS) monitoring system. Four validation methods include the 32-Day Average, CRTM-DD, SNO, and Sensor-DD via SNO—to enhance monitoring and detect radiometric errors. The results demonstrate that the SDR data quality from three OMPS nadir instruments and three CrIS instruments aboard the SNPP, NOAA-20, and NOAA-21 satellites has generally remained stable over the long term, meeting scientific requirements with some margin—mainly during early orbit phases, anomalies, malfunctions, or calibration updates. Among four methodologies, the 32-Day method excels in identifying limitations of other used validation methods, particularly in terms of inter-sensor bias geographical coverage. For instance, the 32-Day method identifies an unusual feature in the NOAA-21 CrIS SDR data over the high latitudes of the Southern Hemisphere during the spring and summer seasons, which was not detected using the other three methods due to a limited coverage. The SNO method is particularly effective for detecting long-term calibration discrepancies in a single instrument. This is illustrated by an approximately 10-year time series of inter-sensor bias between SNPP OMPS Nadir Mapper and Metop-B GOME-2, which reveals significant degradation in GOME-2. Using the SNO method, two significant geolocation problems occurred on SNPP spacecraft were captured in inter-sensor biases between SNPP CrIS and GOES-16 ABI. Therefore, the iSensor-RCBA portal can serve as a crucial tool for providing supplemental information about long-term radiometric calibration stability of satellite radiance data across JPSS and other satellite instruments.

The Advanced Baseline Imager (ABI) is the primary instrument onboard the NOAA Geostationary Operational Environmental Satellite-R Series (GOES-R) satellites, providing continuous weather imagery over the vast area in the Western Hemisphere. It is imperative to ensure consistent calibration accuracy within the instrument’s field of regard (FOR). This paper characterized the spatial uniformity in the east–west (EW) direction for the six ABI visible and near-infrared (VNIR) bands of the first two GOES-R satellites, GOES-16 (G16) and GOES-17 (G17), using a special collection of lunar chasing images during their post-launch testing and post-launch product testing (PLT/PLPT) periods. The EW response versus scan-angle (RVS) is examined with the normalized lunar irradiance ratios at varying scan angles combined from multiple lunar-chasing events. The impacts of straylight from the Earth were found in some of the B01–B03 lunar images. The straylight, including those scattered into the spacelook scenes near the polar regions and those leaked into space near the Moon, can cause RVS variation up to 1% for B01 and to a lesser magnitude for the other two bands. Straylight correction algorithms are applied for the accurate ABI lunar image irradiance calculation. After the corrections, the RVS variation is reduced to less than 0.3% for all the VNIR bands of both G16/17 in full-disk (FD) images. Results of this study also confirm that the Global Space-based Inter-Calibration System (GSICS) Implementation of the ROLO (GIRO) model has high relative accuracy for the ABI VNIR bands when the lunar images are collected within a relatively short time. The method described in this paper can be applied to validate the EW spatial uniformity for imagers on other geostationary satellites, including the recently launched GOES-18 and the future GOES-U satellites.

Stray light rejection around local midnight during eclipse season is a unique challenge for satellite instrument on geostationary orbit, especially for a 3-axis stabilized platform such as the Advanced Baseline Imager (ABI) on the U. S. Geostationary Operational Environmental Satellite (GOES-16/17/18), the Advanced Himawari Imager (AHI) on Japan’s Himawari-8/9 satellites, and the Advanced Meteorological Imager (AMI) on Korea’s GEO-KOMPSAT-2A satellite. In this study, we use the data collected in fall 2022 to compare the straylight rejection performance for the infrared (IR) channels of these instruments, all built by the same manufacture. Since straylight contamination is most pronounced in the 3.7 µm channel, the straylight magnitude in this channel is estimated for the six instruments and compared with each other. The results show that the three ABIs met the requirements, with GOES-17 slightly worse than GOES-16 and GOES-18 noticeably better than GOES-16/17. Both Himawari-8/9 AHIs are subject to serious stray light contamination, including the bands of straylight far away from the Sun that is due to the “sneak path”. Launched in October 2014, Himawari-8 is the first satellite with ABI-type instrument. Thanks to Japan Meteorological Agency (JMA) who shared early AHI-8 results with NOAA, the manufacture was able to improve the straylight rejection for the following flight modules, which proves to be successful. The AMI data is currently being processed; the results will be reported to the conference.

Lunar surface reflectance is considered extremely stable. This property has been used to validate the stability of satellite instrument calibration for reflective solar bands (RSB), such as Channels 1-6 of the Advanced Baseline Imager (ABI) onboard the Geostationary Operational Environmental Satellite (GOES). A common method is to compare the measured and modeled lunar irradiance over time. An early lunar irradiance model, the Robotic Lunar Observatory (ROLO) model, was released by the Global Space-based Inter-Calibration System (GSICS) as GSICS Implementation of the ROLO (GIRO) model. Another lunar irradiance model, the Spectral Lunar Irradiance Model Effective wavelength methodology (SLIM), was published recently. In this study, we evaluate these two models using regularly collected ABI lunar observations, with special attention to their dependence on lunar phase angle in the visible bands for B01-B02 (0.47 – 6.4 μm) and near-infrared bands for B03-B06 (0.86 – 2.3 μm). It was found that GIRO model performs well for 0.47 – 0.9 μm range but is biased for images of small lunar phase angle, and the bias increases with wavelength. SLIM model substantially corrected these biases, and the residual bias may be further reduced empirically. The SLIM model consistently predicts higher, and closer to ABI, irradiance values than the GIRO model across all ABI visible and nearinfrared (VNIR) channels.

Abstract. The advanced baseline imager (ABI) on board geostationary operational environmental satellite-16 (GOES-16) provides high quality reflective solar band (RSB) and thermal emission band (TEB) image data. Intensive field campaigns for postlaunch validation of the ABI Level-1B spectral radiance observations were carried out during March to May of 2017 to ensure the Système International traceability of the ABI. Radiometric calibrations of the RSBs and TEBs of the ABI were evaluated by comparison with the spectral measurements of the airborne visible infrared imaging spectrometer-next generation (AVIRIS-NG) and scanning high-resolution interferometer sounder (S-HIS) on board the high-altitude aircraft ER2, respectively. The comparison between ABI RSB mesoscale (MESO) data and AVIRIS-NG measurements showed that the mean biases are within 2% with uncertainty <2.5  %   for ABI CH01, CH03, CH05, and CH06. The brightness temperature differences between GOES-16 ABI and S-HIS measurements were shown to be within 0.45 K with uncertainty <0.35 K at the 300 K scene equivalent for ABI CH08 to CH10 and CH13 to CH15. The ABI uses large focal plane arrays with the detector number varying from hundreds to more than a thousand per channel, which makes the evaluation of detector uniformity a challenge. Reanalysis of the GOES-16 ABI north-south scan data from the field campaign and lunar observation was performed for ABI CH01 to CH03 with two versions of calibration coefficients. Significant improvements in detector uniformity with the updated solar calibration algorithm were verified.

The Advanced Baseline Imager (ABI) instrument is the key payload onboard NOAA’s series of Geostationary Operational Environmental Satellites (GOES-R) that provides high-quality earth imagery to improve the weather forecasts and environmental change studies over the Western Hemisphere. GOES-16 was launched on 19 November 2016 and became the GOES-East satellite at 75.2 West on 18 December 2017. As the first satellite in the series, it overcame a number of anomalies in the first few years of operation but has performed well since the calibration was stabilized in April 2019. On the other hand, GOES-17, launched on 1 March 2018 and became GOES-West at 137.2 West on 12 February 2019, suffered a malfunction of the cooling system, which called for quite a different operation and calibration configurations. This talk is a summary of the on-orbit radiometric calibration performances for the GOES-16/17 ABI Infrared (IR) channels. The GOES-16 IR radiance is well calibrated and very stable at various temporal and spatial scales after the two major IR ground system updates in its early in-orbit time. The overall radiometric calibration accuracy of GOES-17 IR channels during the stable period is comparable with that of GOES-16. One exception is that the bias to the reference is relatively large for GOES-17 Ch16 due to the shift of its spectral response function caused by the elevated operational temperature. This talk will also include the impacts of the major calibration events for the GOES-17 ABI IR data after its operation, including the implementation of the predictive calibration (pCal) algorithm in July 2019 to improve the radiometric calibration accuracy at satellite night time, salvaged imagery with the cooling timeline in the peak thermal stress days around the eclipse seasons, change of FPM set-point temperatures in late 2021 and early 2022, and the large-scale best detector select (BDS) updates in December 2021.

Six channels of the Advanced Baseline Imager (ABI) onboard the Geostationary Operational Environmental Satellite (GOES) sense radiance in the visible and near infrared (VNIR) spectrum. Two ABI have been launched and in service, one with GOES-16 at 75.2oW and the other with GOES-17 at 137.2oW. Unlike the GOES infrared channels that have had onboard calibration since the 1970’s, ABI is the first GOES instrument that is equipped with onboard calibration for its RSB. This paper reviews the operational calibration of the ABI VNIR channels, including initial post-launch calibration, correction for elevation angle variation, and correction for azimuth (beta) angle variation. GOES-17 suffers from a compromised cooling subsystem such that the instrument temperature, including that for the VNIR Focal Plane Module, varies more than designed. The impact and mitigation of this thermal stress will also be described. Finally, GOES-18 will be launched in 1 March 2022. It is expected that some preliminary calibration results of GOES-18 will be available for discussion. Declaimer: The scientific results and conclusions, as well as any views or opinions expressed herein, are those of the authors and do not necessarily reflect those of NOAA or the Department of Commerce.

Abstract The Advanced Baseline Imager (ABI) is the primary instrument onboard NOAA’s current generation of Geostationary Operational Environment Satellites R-series (GOES-R) satellites, measuring the reflected and emitted energy from the Earth. It consists of 16 channels, 10 in the thermal infrared (IR) and 6 in the solar reflective spectrum. Being the first in the GOES-R series satellites, GOES-16 was launched on November 19, 2016, and became operational as GOES-East at 75.2°W since December 18, 2017. We examine the radiometric calibration accuracy and stability of GOES-16 ABI IR radiance since its first light in January 2017, including the effects of two major updates of the GOES-R Ground Segment processing for the IR channels in October 2017, and June 2018. Using measurements by multiple hyperspectral radiometers from low Earth orbit satellites as references, it is found that, when converted to scene brightness temperature of 300 K, the calibrated ABI IR radiance is accurate within 0.13 K for Ch16 (13.3  μm), within 0.06 K for channel 12 (9.6  μm), and within 0.05 K for the other IR channels. This is an order of magnitude better than the requirement of 1 K. Since June, 2018, the radiometric calibration of GOES-16 ABI IR channels has been temporally stable, spatially uniform within the ABI full-disk field of view, absent of diurnal and seasonal variations, and invariant within various timelines. Other than short term disruptions as noted in the Calibration Event Log, GOES-16 ABI IR Level 1b products since June 19, 2018, is a reliable reference for satellite intercomparison or intercalibration studies.

The Advanced Baseline Imager (ABI) aboard Geostationary Operational Environmental Satellite (GOES)-16 and -17 satellites represent the next-generation geostationary multispectral imaging instrument. Since GOES-16 ABI imagery data became available, stray light was observed in ABI visible, near-infrared (VNIR), and 3.9 mu m, i.e., CH07, channels. A stray-light characterization scheme was developed to quantitatively monitor stray-light variation in ABI imagery. The stray-light analysis is focused on ABI CH07, whose nighttime radiometric performance being impacted by stray light is of main concern. It is found that the stray light in the ABI imagery occurs over similar to 3 months around spring and fall equinox each year. The maximum stray light of GOES-16 ABI CH07 is similar to 0.65 K at 300 K scene in zone of normal performance (ZONP), i.e., region with relative solar angle >7.5 deg, which is within the radiometric requirement of 1 K. The analysis of Himawari-8 Advanced Himawari Imager (AHI) CH07 data indicates that its maximum stray light is similar to 3.35 K at 300 K scene in ZONP, much higher than that of GOES-16. This confirms the effectiveness of reducing the major stray-light leaking path in ABI as a result of lessons learned from Himawari-8 AHI. The magnitude of GOES-17 ABI CH07 stray light is shown to be similar to 0.45 K in ZONP, slightly lower than GOES-16. The analysis of AHI 3.9 and 6.2 mu m channel stray-light radiance ratio is shown to match the ratio of solar irradiance spectrum, which suggests that the stray-light issue is due to direct leakage of solar radiation through the instrument. Further characterization and monitoring of GOES-16 ABI VNIR channel stray light also help understand the solar origin of ABI stray light. This paper also investigated cases of strong atmospheric refraction-induced stray-light contamination onto ABI detectors during solar eclipse seasons and presents scheme to reduce such potentially harmful contamination. (C) The Authors.

Two flight models of the Advanced Baseline Imager (ABI) are in-orbit on the GOES-16 and GOES-17 geostationary satellites, with two more planned to be launched on GOES-T (2021) and GOES-U (2024). The ABI is the primary Earth-viewing weather imaging instrument on the GOES-R Series, producing Level 1b (L1b) radiances and Cloud and Moisture Imagery (CMI) data products. The ABI L1b product is the source for all the ABI Level 2+ (L2+) products, including CMI, which makes the maturity process for these two products important. CMI is the only key performance parameter (KPP) of the GOES-R Series mission and thus CMI takes precedence over other ABI L2+ products. As the only KPP, CMI follows the same maturity schedule as the ABI L1b product. For the ABI L1b and CMI data products to be declared operational, they must pass through a series of calibration and validation tests and analyses, with the peer-reviewed results showing that the instruments and products have achieved each level of maturity consistent with mission success. This paper describes the assessment process, the definitions of the product validation maturity levels, and an overview of the product performance for each instrument at each validation level. Additionally, this paper will describe planned programmatic changes aimed at streamlining the maturity process for the upcoming GOES-T and GOES-U satellites.

The Advanced Baseline Imager (ABI) on GOES-17 also has six Visible and Near Infrared (VNIR) bands that are calibrated periodically using a solar diffuser. Unlike GOES-16, however, GOES-17 suffers from a Loop Heat Pipe (LHP) anomaly that reduced its cooling capacity. As a result, temperature of the Focal Plane Module (FPM) for its VNIR channels can fluctuate diurnally from 185 K to 202K, and the magnitude of this diurnal fluctuation varies seasonally. We found that the VNIR bands gain depends on FPM temperature fluctuation, the correlation is positive for some channels and negative for other channels, and some channel is more sensitive to FPM temperature than others. Such variation creates calibration uncertainty since the gain is determined at one FPM temperature and used to calibrate earth view data collected when the FPM is at a different temperature.To reduce these impacts, several operational mitigation schemes have been proposed and are currently under implementation evaluations.

The Journal of Applied Remote Sensing (JARS) is an online journal that optimizes the communication of concepts, information, and progress within the remote sensing community to improve the societal benefit for monitoring and management of natural disasters, weather forecasting, agricultural and urban land-use planning, environmental quality monitoring, ecological restoration, and numerous other commercial and scientific applications.

GOES-17 was launched on March 1, 2018, and became GOES-West at 137.2°W on February 12, 2019. The Advanced Baseline Imager (ABI) onboard GOES-17 has 16 bands to provide continuous data stream for weather forecasting and disaster monitoring. This poster summarizes the monitoring of GOES-17 calibration performance at the GOES-R Calibration Working Group (CWG), including radiometric, geometric, and spectral calibration. We monitor instrument calibration measurements and parameters, as well as the quality of the radiance product, including various accuracy and stability metrics of radiometric and geometric calibration. Our monitoring system has been an invaluable asset to users for instrument and products status, to instrument vendors for instrument anomaly diagnosis, to ground system vendors for software upgrade verification, to payload engineers for operational anomaly diagnosis, and to program managers for situational awareness. Several examples will be provided.

The ABI instrument on GOES-17 suffers from insufficient cooling, resulting in degradation in the L1b radiance products during times of excessive solar heating, partially due to the original calibration algorithm assuming only a slowly-varying thermal state. In 2019 a modification of the calibration algorithm (named “Predictive Calibration”) was introduced as part of the mitigation strategy. We summarize the early evaluation of L1b products created with this modified algorithm. We also describe some of the imagery artifacts sometimes introduced into the GOES-17 ABI L1b data by the Predictive Calibration or other mitigation steps.

Quantifying Geostationary Operational Environmental Satellite R-series (GOES-R) Advanced Baseline Imager (ABI) Channel (Ch) 2 low-light signal-to-noise ratio (SNR) is a core ABI postlaunch product test to validate prelaunch performance expectations of this parameter. For GOES-16, an SNR analysis has been performed to accomplish this goal using ABI Mode-3 MESO visible near-infrared (VNIR) channel L1b radiance product images taken every 30 s between 17:00 UTC and 17:15 UTC on May 23, 2017. Scene pixel data used in the analysis are first screened to ensure they meet the low-light criteria and to minimize scene temporal variability associated with meteorological evolution and geolocation uncertainty in highly inhomogeneous scenes. After such screening, image-to-image radiance time difference statistics are compiled and analyzed to estimate instrument SNR. Based on GOES-R ABI vendor prelaunch testing, minimum and mean expected ABI Ch 2 postlaunch SNR performance at 5% albedo was estimated to be 44.2 and 64.5, respectively. Meanwhile, the SNR computed in this analysis is found to be about 57 +/- 8. Thus, low-light SNR for ABI Ch 2 is shown to meet minimum user expectations. The analysis for the other five GOES-16 ABI VNIR channels is also shown to contrast the SNR for these channels. (C) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License.

The Advanced Baseline Imager (ABI) on-board NOAA’s current Geostationary Operational Environmental Satellite (GOES-16/17) generates a suite of operational products. In October 2017, users and the developer of the fire product reported anomalously cold pixels around fires (CPAF) in the Level 1b 3.9 um channel imagery. Without correction, this anomaly can results in bias of hundreds of degrees for selected pixels. This anomaly was found to be very common in that imagery, though often not immediately discernable. The GOES Calibration Working Group (CWG) investigated this anomaly and found the root cause. Based on this analysis, the ABI vendor revised the re-sampling kernels for the 3.9 um channel, which was successfully implemented into the ground processing system in April 2019. The CPAF anomaly has been eliminated from the L1b 3.9 um imagery since then.

Time series generated from NOAA operational satellite sensor temperature, noise, and calibration parameter statistics is a critical science analysis tool to trend instrument performance and detect and resolve on-orbit anomalies. Establishing this capability entails ingesting instrument engineering, housekeeping, and calibration data; performing statistics on them; and then storing and providing the resultant data and/or plots. For instruments with relatively small amounts of input and output data, this is a relatively easy task. For the NOAA Geostationary Operational Environmental Satellite R-Series Advanced Baseline Imager (ABI)-with three times more spectral information, four times the spatial resolution, and more than five times faster temporal coverage than previous GOES-instrument performance monitoring can be extremely complex because of the relatively large data volumes and number of parameters. Also of difficulty is that software and computing architecture needed to build such a system is usually proprietary and not openly documented. In order to fill this gap, we focus on the concept of operations and the results associated with the ABI instrument performance monitor. This monitoring system has proven to be extremely valuable in tracking instrument stability and detecting and performing initial diagnosis of ABI anomalies. (C) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.