| Number | Name | Time | Fuction | Source |
|---|---|---|---|---|
| 1 | Meteorological station data | 1977-2017 | Calculating the value of N | National Meteorological Information Centre of China ( |
| 2 | Monthly air temperature reanalysis data | 1900-2017 | Calculating the freezing/thawing indices | University of Delaware ( |
| 3 | Land cover data | 2020 | Calculating the value of N | National Geomatics Center of China ( |
| 4 | Soil moisture data | 2002-2018 | Calculating the correlation between freezing/thawing indices and soil moisture | National monthly scale soil moisture dataset ( |
| 5 | Frozen ground map of China | 1998 and 2000 | Accuracy evaluation | National Tibetan Plateau Data Center ( |