Fig 1.
Schematic diagram of the installation layout of the frozen soil automatic observer.
Fig 2.
Distribution of frozen soil automatic observer.
Table 1.
Basic parameter row format of frozen soil minute data file.
Table 2.
Size and order of Seasonal frozen soil minute data file.
Fig 3.
Schematic diagrams of optimal matching at the upper and lower limits of frozen soil layers: (A) Automatic observation includes more layers than manual observation; (B) Fewer layers are observed automatically compared to manual observation; (C) The same number of layers is observed by both automatic and manual methods.
Fig 4.
Schematic diagram of consistency comparison of observation data between automatic observer and TB1-1.
Fig 5.
Example diagram of freeze-thaw trend of frozen soil automatic observer and TB1-1 data.
Table 3.
Installation and inspection and evaluation results of five automatic observers from 2020 to 2024.
Fig 6.
Box plot of the differences in the five indicators between 2022 and 2024: (A) data integrity rate; (B) standard deviation; (C) consistency rate; (D) misjudgment mean; (E) data correlation.
Fig 7.
Comparison of quantity of 2022—2024.
Fig 8.
Distribution diagram of operation stage of automatic observer.