<p>Using the Google Earth Engine (GEE) platform, a long-term AVHRR snow cover extent (SCE) product from 1981 until 2019 over China has been generated by the snow research team in the Northwest Institute of Eco-Environment and Resources (NIEER), Chinese Academy of Sciences. The new NIEER product has the spatial resolution of 5-km and the daily temporal resolution, and is a completely gap-free product, which is produced through a series of processes such as the quality control, cloud detection, snow discrimination and gap-filling. A comprehensive validation with reference to ground snow-depth measurements during snow seasons in China revealed the overall accuracy is 87.4 %, the producer’s accuracy was 81.0 % the user’s accuracy was 81.3 %, and the Cohen’s kappa value was 0.717. Another validation with reference to higher-resolution snow maps derived from Landsat-5 Thematic Mapper (TM) images demonstrates an overall accuracy of 89.4 %, a producer’s accuracy of 90.2 %, a user’s accuracy of 96.1 %, and a Cohen’s kappa value of 0.713. These accuracies were significantly higher than those of currently existing AVHRR products. For example, compared with the well-known JASMES AVHRR product, the overall accuracy increased approximately 15 percent, the omission error dropped from nearly 40 % to 19.7 %, the commission error dropped from 31.9 % to 21.3 %, and the CK value increased by more than 114 %. The new AVHRR product is now already available at <a href="https://dx.doi.org/10.11888/Snow.tpdc.271381" target="_blank" rel="noopener">https://dx.doi.org/10.11888/Snow.tpdc.271381</a> (Hao et al. 2021).</p>