Evaluation of the Radiometric Performance of FY-3D MERSI-II Using Dome C, Antarctica

Continuous monitoring and assessment of satellite sensor radiometric response are crucial for timely detection of anomaly of the sensor performance, especially for operational optical sensors (e.g., FY-3D MERSI-II) beyond the expected lifespan. Improving calibration coefficients ensures the acquisition of high-precision and consistent observational Level 1 data records for long time-series researches. To evaluate the radiometric response stability of FY-3D MERSI-II in the reflective solar band, this study constructs parametric simplified and nonsimplified Warren bidirectional reflectance distribution function (BRDF) models using FY-3D MERSI-II nadir observation data at Dome C, Antarctica during the austral summer (October–February in next year) from 2019 to 2023. Subsequently, BRDF correction is applied to eliminate variations in the Dome C data caused by its non-Lambertian nature. The corrected data are analyzed for trends and compared with previous publications. The findings indicate that parameter simplification results in this study improve the calibration accuracy for band 3 (0.650
$\bm {\mu }\text{m}$
) and band 4 (0.865
$\bm {\mu }\text{m}$
) by 18.1% and 9.5%, respectively. Further analysis for the instrument degradation reveals that [the total multiyear degradation rate, average annual degradation rate] are within [
$\pm$
2.2%,
$\pm$
0.54%] and [
$\pm$
0.5%,
$\pm$
0.13%], respectively. Comparative validation results demonstrate good agreement with previous studies, showing a deviation of the average annual degradation rate between corresponding bands within
$\pm$
1%. It demonstrates that the stability of the MERSI-II is comparable to MODIS, which is one of the most frequently used medium-resolution sensors over last 25 years.