Experimental data in the manuscript
1. Accuracy validation at 425 global test sites
A total of 425 test sites that distributed across the globe are selected using a stratified sampling method, each of which covers a 6 km * 6 km area. These test sites were grouped by their land cover types (of the center pixel) using the FROM_GLC land cover map (Gong et al., 2013; Li et al., 2017). Fig. 1 shows the spatial distribution and corresponding land cover types of the 425 global test sites.
The leave-one-out validation strategy is employed to evaluate the CSDC reconstruction accuracy (Chen et al., 2023). For each Landsat image at each test site, we exclude it from the input data and applied CSDC reconstruction with the remaining data. Then, the reconstruction accuracy is evaluated by comparing the reconstructed and original Landsat images using standard metrics, such as Correlation Coefficient (CC), Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and rMAE (MAE normalized by true surface reflectance values). The accuracy assessment is conducted in five years (1991, 2001, 2004, 2012, 2021) representative of different input data conditions.
| File | Description |
| 1. acc_val_2001_2021.zip | reconstructed CSDC and original Landsat data in 2001, 2004, 2012, and 2021. |
| 2. acc_val_1991.zip | reconstructed CSDC and original Landsat data in 1991 |
2. Cross-comparison with HLS
Product quality control is conducted with a cross-comparison between the CSDC and HLS S30/L30 products. We selected 22 MGRS tiles representative of different land cover types as test sites and evaluated the agreement between the reconstructed CSDC data and the HLS data. Fig. 2 shows the spatial distribution of the 22 MGRS tiles in the cross-comparison. Each test site covers a 109.8km * 109.8km area. Since the L30 product are derived from Landsat OT data, we employed the leave-one-out validation strategy (the same as in last section) for the cross-comparison with L30 data. The least square regression method was used to reduce spectral bandpass differences between the CSDC and HLS data for each spectral band and each test site.
The reconstructed CSDC data at these MGRS tiles will be made available at: http://data.starcloud.pcl.ac.cn/zh/resource/26. The HLS data can be downloaded from EarthData.
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