2.2.2. Snow Cover Data

The MODIS snow cover data MOD10A2, with a 500 m spatial resolution and 8-day intervals, was used to derive snow phenology parameters in our study. This snow cover product has higher spatial and temporal resolutions [43]. Previous studies have verified that MOD10A2 is effective in reducing the effect of cloud contamination in most cases and has higher classification accuracy than another MODIS snow product (MOD10A1) [37,44]. A total of 46 images from 1 January 2020 to 31 December 2020 were freely downloaded from the National Snow and Ice Data Center (NSIDC, http://nsidc.org (accessed on 17 December 2021)). All images were processed to UTM/WGS-84 projection and 500 m resolution. Pixels coded as '200 were extracted as snow pixels according to the product's user guide [43].
