Comment on essd-2021-432

The authors proposed a comprehensive framework to process GNSS raw data under complex environment conditions to retrieve snow depth, and based on this, the authors produced a GNSS-based long-term snow depth data set over China from 80 stations. The topic is very interesting from a perspective different from traditional microwave remote sensing retrievals. As the authors’ statement, this data set has a unique spatial resolution between point-scale and coarse grid-scale. The new data set is valuable to the science community from this point. I also have confidence in this GNSS-IR technique, which could be a helpful and complementary tool for producing more snow depth products with high spatial-temporal resolution using extended global GNSS networks, particularly from GNSS sites in polar regions or even on scientific expedition vessels.