Zeng, Q.; Wu, X.; Tang, R.; Wang, J.; Lin, X.; Wen, J.; Xiao, Q. Quantification of Uncertainty Caused by Geometric Location Mismatch in the Validation of TROPOMI Solar-Induced Chlorophyll Fluorescence Product. International Journal of Digital Earth 2024, 17, doi:10.1080/17538947.2024.2330688.
Zeng, Q.; Wu, X.; Tang, R.; Wang, J.; Lin, X.; Wen, J.; Xiao, Q. Quantification of Uncertainty Caused by Geometric Location Mismatch in the Validation of TROPOMI Solar-Induced Chlorophyll Fluorescence Product. International Journal of Digital Earth 2024, 17, doi:10.1080/17538947.2024.2330688.
Zeng, Q.; Wu, X.; Tang, R.; Wang, J.; Lin, X.; Wen, J.; Xiao, Q. Quantification of Uncertainty Caused by Geometric Location Mismatch in the Validation of TROPOMI Solar-Induced Chlorophyll Fluorescence Product. International Journal of Digital Earth 2024, 17, doi:10.1080/17538947.2024.2330688.
Zeng, Q.; Wu, X.; Tang, R.; Wang, J.; Lin, X.; Wen, J.; Xiao, Q. Quantification of Uncertainty Caused by Geometric Location Mismatch in the Validation of TROPOMI Solar-Induced Chlorophyll Fluorescence Product. International Journal of Digital Earth 2024, 17, doi:10.1080/17538947.2024.2330688.
Abstract
Validation of the TROPOspheric Monitoring Instrument (TROPOMI) SIF product is a necessity to evaluate its feasibility in various applications. A few validation works have been conducted through direct comparison with in-situ SIF retrievals or cross-comparison with similar satel-lite-based SIF or vegetation index (VI) products. Nevertheless, the influence of the geolocation mismatch between the validation pixel and reference data on validation results was never con-sidered. This study, for the first time, quantifies the geolocation shift of the TROPOMI validation pixel based on a geometric location matching method and then the uncertainty caused by the ge-olocation mismatch. The results indicate that the geolocation shift of the TROPOMI pixel shows large temporal variations, with a standard deviation of 2.45 km and 1.96 km in the across- and along-track directions. The mean shifts are 0.07 km and 0.25 km in the across- and along-track directions respectively, indicating eastward shifts in the across-track direction and northward shifts in the along-track direction in general. More than half (42/54) of the time periods showed relative uncertainty larger than 5%, with the maximum even reaching 55.7%. Hence, the uncertainty caused by geolocation mismatch should be fully considered in the validation of satellite SIF products, especially over heterogeneous surfaces.
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
