5 research outputs found
Recommended from our members
Evaluation of vicarious calibration for airborne sensors using RadCalNet
Vicarious calibration approaches using in-situ measurements are key techniques applied to on-orbit remote sensors. The in-situ measurements have advantages in terms of traceability and quantifiable accuracy that make them ideal for inter-consistency studies of on-orbit sensors. The Committee on Earth Observation Satellites Working Group on Calibration and Validation Infrared Visible Optical Sensors initiated the Radiometric Calibration Network (RadCalNet) to provide automated surface and top-of-atmosphere (TOA) reflectance data from multiple participating ground sites to the worldwide user community. RadCalNet standardizes protocols for collecting data, processes TOA reflectance, and provides International System of Units traceable uncertainty budgets for the five currently operating sites. RadCalNet data from the Railroad Valley Playa, Nevada, site was used to provide an SI-traceable, absolute radiometric calibration of the Enhanced MODIS Airborne Simulator as part of an overflight of opportunity during the FIREX-AQ campaign. The results shown here demonstrate the utility of RadCalNet data for absolute radiometric calibration of airborne imagers making flights of opportunity without the need for coordination with a field validation team. © 2021 Society of Photo-Optical Instrumentation Engineers (SPIE).Immediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Recommended from our members
Radiance-based and Reflectance-based Retrievals of Surface Reflectance for Vicarious Calibration
A field deployable transfer radiometer has been developed as part of an effort to ensure the quality of upwelling radiance at automated test sites used for vicarious calibration in the solar reflective. Ground-based radiometer measurements of the surface combined with knowledge of the atmospheric state can be used to predict top-of-atmosphere reflectance and radiance. This work discusses two pathways with independent traceability of deriving the surface reflectance, namely a radiance-based and reflectance-based approach. The radiance-based retrieval converts the upwelling radiance reported by the radiometer to reflectance using radiative transfer calculations and atmospheric characterization data. The reflectance-based approach converts measurements by the radiometer of the surface to reflectance through ratios to data collected while viewing a diffuser reference of known reflectance. The results from both traceability paths are obtained using the same radiometer data sets, thus allowing analysis of any resulting differences. Field radiometer data collected at a desert site in the western US coincident with overpass of the Landsat 8 OLI sensor are analyzed to understand the impact of the two approaches on predictions of both the top-of-atmosphere reflectance and radiance. The comparison between the two traceability paths shows clear differences, but these differences are within the combined uncertainties of the two approaches. © 2023 SPIE · 0277-786X.Immediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Recommended from our members
Intercomparison of Landsat Operational Land Imager and Terra Advanced Spaceborne Thermal Emission and Reflection Radiometer Radiometric Calibrations Using Radiometric Calibration Network Data
This paper presents a comprehensive intercomparison study investigating the radiometric performance of and concurrence among the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Landsat 8 Operational Land Imager (L8 OLI), and Landsat 9 OLI (L9 OLI) instruments. This study leverages data sourced from the Radiometric Calibration Network (RadCalNet) and focuses on spectral bands relevant for vegetation analysis and land cover classification, encompassing a thorough assessment of data quality, uncertainties, and underlying influencing factors. This study’s outcomes underscore the efficacy of RadCalNet in evaluating the precision and reliability of remote sensing data, offering valuable insights into the strengths and limitations of ASTER, L8 OLI, and L9 OLI. These insights serve as a foundation for informed decision making in environmental monitoring and resource management, highlighting the pivotal role of RadCalNet in gauging the radiometric performance of remote sensing sensors. Results from RadCalNet sites, namely Railroad Valley Playa and Gobabeb, show their possible suitability for sensors with spatial resolutions down to 15 m. The results indicate that the measurements from both ASTER and OLI closely align with the data from RadCalNet, and the observed agreement falls comfortably within the total range of potential errors associated with the sensors and the test site information. © 2024 by the authors.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Recommended from our members
Intercomparison of Landsat OLI and Terra ASTER solar reflective calibrations using the Radiometric Calibration Network data from Railroad Valley, Nevada
This paper presents an intercomparison study between the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Landsat 8 Operational Land Imager (OLI) using data from the Radiometric Calibration Network (RadCalNet). The study evaluates the radiometric performance and agreement between ASTER and Landsat 8 OLI, focusing on their spectral bands relevant for vegetation analysis and land cover classification. The analysis includes the assessment of data quality, uncertainties, and factors influencing the measurements. The results demonstrate the usability of RadCalNet in evaluating the accuracy and reliability of remote sensing data. The findings contribute to our understanding of the strengths and limitations of ASTER and Landsat 8 OLI, supporting informed decision-making in environmental monitoring and resource management. Overall, the intercomparison study provides valuable insights into the capabilities and limitations of ASTER and Landsat 8 OLI, highlighting the importance of RadCalNet in assessing the radiometric performance of remote sensing sensors. The results from the Railroad Valley RadCalNet show that the site is suitable for sensors with spatial resolutions as small as 15 m. The comparison between ASTER and OLI demonstrates that the recent update to the ASTER radiometric calibration provides results that are in agreement with Landsat 8 OLI to well within the absolute radiometric uncertainties of both sensors. © 2023 SPIE · 0277-786X.Immediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]