If you used our dataset, please cite our reference: Jing, Y., Li, X., and Shen, H.: STAR NDSI collection: a cloud-free MODIS NDSI dataset (2001–2020) for China, Earth Syst. Sci. Data, 14, 3137–3156, https://doi.org/10.5194/essd-14-3137-2022, 2022. 1. A recent 20-year cloud-free MODIS normalized difference snow index (NDSI) collection for China (excluding sea area) is generated using a Spatio-Temporal Adaptive fusion method with erroR correction (STAR). 2. The STAR NDSI collection is derived from daily 1-km MODIS NDSI datasets (MOD10A1 and MYD10A1). 3. It is provided using a WGS_1984_UTM_48N projection, with the data format of TIFF images. 4. Each ZIP contains NDSI data for one hydrological year (August to next July). After uncompressing into the TIFF format, the files are named as "NDSI_ yyyymmdd_Daily_500M_ V01.tif" for NDSI data and "QA_yyyymmdd_Daily_500M_V01.tif" for quality assessment (QA) data. 5. The accuracy of this collection has been well validated by the in-situ snow depth observations and Landsat OLI NDSI maps. The detailed information can be found in the published paper. 6. The NDSI value ranges from 0, 1-100. The value of water is set to 255. The fill value is set to 127. 7. Disclaimer: The spatial scope of the dataset is for research convenience. Please refer to official release for a standard map of China, http://211.159.149.56/index.html. 8. The new version includes data from 2001 to 2020, while the old version includes data from 2012 to 2020 (https://doi.org/10.5281/zenodo.5644386). 9. In case any questions arise, please do not hesitate to contact us (yhjing@whu.edu.cn).

{"references": ["Jing, Y., Li, X., and Shen, H.: STAR NDSI collection: a cloud-free MODIS NDSI dataset (2001\u20132020) for China, Earth Syst. Sci. Data, 14, 3137\u20133156, https://doi.org/10.5194/essd-14-3137-2022, 2022."]}