Evaluating the geolocation accuracy of FY-3D MERSI-II satellite image in Antarctica based on Landsat 8-OLI reference imagery

The Antarctic Ice Sheet is one of the largest potential contributors to global sea level rise. As mass loss has intensified since the 21st century, there is an increasing urgency for high-precision, full-coverage, and continuous monitoring of the Antarctic. With 250-m spatial resolution and 5-min temporal resolution, the Medium-Resolution Spectral Imager II (MERSI-II) sensor aboard the Fengyun-3D (FY-3D) satellite provides a solid data foundation for Antarctic change detection. However, its geolocation performance in Antarctic has not yet been systematically evaluated. This study proposes a sub-pixel geolocation accuracy evaluation method tailored for 250-m MERSI-II data by integrating frequency-domain cross-correlation and outlier isolation techniques. Using MERSI-II data over major rock outcrop areas of Antarctica and monthly Landsat 8-OLI composites generated via Google Earth Engine (GEE), the method quantifies the Level 1 dataset’s geometric displacements in the along-track and cross-track directions. The results reveal the spatiotemporal characteristics of the FY-3D MERSI-II onboard geolocation accuracy across Antarctica. Overall, MERSI-II exhibits a consistent geolocation bias pattern characterized by the majority of geolocation displacements along the track are negative, while most displacements across the track are positive. The mean along-track error is 87.5 [Formula: see text] 19.5 m, with 96.1% of values below 125 m, while the mean cross-track error is 82.5 [Formula: see text] 15.8 m, with 99.5% below 125 m. These results are in good agreement with previous researches. This study reliably ascertains that the geolocation accuracy of MERSI-II over the Antarctic remains within 1/2 of the Instantaneous Field of View (IFOV).