MODIS Daily Cloud-gap-filled Fractional Snow Cover Dataset of the Asian Water Tower Region (2000-2022)

The Asia Water Tower region, with the Qinghai-Tibet Plateau at its core, is the most widespread region of snow cover on Earth, except for the North and South Poles. The topographic heterogeneity of the Asian Water Tower region is so great that the snow cover is thin and patchy, resulting in a highly time-varying snow cover in the region, and therefore daily-scale fractional snow cover data are urgently needed. This dataset is based on the MODIS surface reflectance product MO/YD09GA product, and the MODIS daily cloud-free fractional snow cover dataset for the Asian Water Tower region from 2000 to 2022 was produced using the MESMA-AGE algorithm and the MSTI algorithm. The high spatial resolution Landsat-8 image was taken as the "ground truth", the RMSE was 0.16, and the MAE was 0.10. This dataset has a time series from 26 February 2000 to 31 December 2022 with a spatial resolution of 0.005°, which can provide quantitative snow cover information on the spatial distribution of snow for mountain hydrological models, land surface models, numerical weather forecasts, etc.以青藏高原为核心的亚洲水塔（Asia Water Tower）区域，是除南北极之外全球积雪分布最广泛的区域。该区域地形异质性极强，积雪薄且分布零散，导致区域内积雪覆盖随时间变化极为显著，因此亟需日尺度的积雪覆盖率数据。本数据集以MODIS地表反射率产品MO/YD09GA为基础，采用MESMA-AGE算法与MSTI算法，生成了2000年至2022年亚洲水塔区域的MODIS每日无云积雪覆盖率数据集。以高空间分辨率Landsat-8影像作为“地面真值（ground truth）”，该数据集的均方根误差（RMSE）为0.16，平均绝对误差（MAE）为0.10。本数据集的时间序列范围为2000年2月26日至2022年12月31日，空间分辨率为0.005°，可为山地水文模型、陆面模型、数值天气预报等提供积雪空间分布的定量化积雪覆盖信息。