Long-term surface soil freeze-thaw states dataset of China using the dual-index algorithm (1978-2015)

This dataset uses daily temperature data from SMMR (1978-1987), SSM/I (1987-2009) and SSMIS (2009-2015). It is generated by the dual-index (TB, 37v, SG) freeze-thaw discrimination algorithm. The classification results include the frozen surface, the thawed surface, the deserts and water bodies. The data coverage is the main part of China’s mainland, with a spatial resolution of 25.067525 km via the EASE-Grid projection method, and it is stored in ASCIIGRID format.

All the ASCII files in this data set can be opened directly with a text program such as Notepad. Except for the head file, the body content is numerically characterized by the freeze/thaw status of the surface soil: 1 for frozen, 2 for thawed, 3 for desert, and 4 for precipitation. If you want to use the icon for display, we recommend using the ArcView + 3D or Spatial Analyst extension module for reading; in the process of reading, a grid format file will be generated, and the displayed grid file is the graphical expression of the ASCII file. The read method comprises the following.

[1] Add the 3D or Spatial Analyst extension module to the ArcView software and then create a new View.

[2] Activate View, click File menu, and select the Import Data Source option. When the Import Data Source selection box pops up, select ASCII Raster in the Select import file type box. When the dialog box for selecting the source ASCII file automatically pops up, click to find any ASCII file in the data set, and then press OK.

[3] Type the name of the Grid file in the Output Grid dialog box (it is recommended that a meaningful file name is used for later viewing) and click the path to store the Grid file, press OK again, and then press Yes (to select integer data) and Yes (to put the generated grid file into the current view). The generated files can be edited according to the Grid file standard. This completes the process of displaying an ASCII file into a Grid file.

[4] In the batch processing, the ASCIGRID command of ARCINFO can be used to write AML files, and then use the Run command to complete the process in the Grid module:


The production of this data is supported by the following Natural Science Foundation Projects: Environmental and Ecological Science Data Center of West China (90502010), Land Data Assimilation System of West China (90202014) and Active and Passive Microwave Radiation Transmission Simulation and Radiation Scattering Characteristics of the Frozen Soil (41071226).

File naming and required software

Data naming format: the data set consists of 37 folders from 1978 to 2015. Each folder includes the daily surface freeze-thaw classification results of the current year. The daily surface freeze-thaw classification results are stored in the format of TXT. The naming rules are "smmr-ftyyyddd. TXT" or "ssmi-ftyyyddd. TXT" or "ssms-ftyyyddd. TXT", where yyyy represents the year and DDD represents the Julian day.
Data reading mode: all ASCII TXT files in this data set can be opened directly with a text program (such as notepad).In addition to the header file, the main content is the numerical representation of the freezing-thawing state of the surface: 1 represents freezing, 2 represents melting, 3 represents desert, and 4 represents precipitation.If the graph is to be displayed, it is recommended to use ArcView + 3D or Spatial Analyst extension module to read. In the process of reading, the grid file will be generated, and the grid file displayed is the graphical expression of the ASCII file.

Data Citations Data citation guideline What's data citation?
Cite as:

JIN Rui, LI Xin. Long-term surface soil freeze-thaw states dataset of China using the dual-index algorithm (1978-2015). National Tibetan Plateau Data Center, 2011. DOI: 10.11888/Geocry.tpdc.270029. (Download the reference: RIS | Bibtex )

Related Literatures:

1. Jin,R, Zhang,T,Y, Li,X, Yang,X,G, Ran,Y,H.(2015). Mapping surface soil freeze-thaw cycles in china based on smmr and ssm/i brightness temperatures from 1978 to 2008. Arctic, Antarctic, and Alpine Research, 47(2), 213-229.( View Details | Bibtex)

2. Xie, Y.M., Jin, R, & Yang, X.G. (2013). Algorithm development of monitoring daily near surface freeze/thaw cycles using amsr-e brightness temperatures. Remote Sensing Technology and Application, 28(2).( View Details | Download | Bibtex)

Using this data, the data citation is required to be referenced and the related literatures are suggested to be cited.

Copyright & License

To respect the intellectual property rights, protect the rights of data authors,expand servglacials of the data center, and evaluate the application potential of data, data users should clearly indicate the source of the data and the author of the data in the research results generated by using the data (including published papers, articles, data products, and unpublished research reports, data products and other results). For re-posting (second or multiple releases) data, the author must also indicate the source of the original data.

Example of acknowledgement statement is included below: The data set is provided by National Tibetan Plateau Data Center (http://data.tpdc.ac.cn).

License: This work is licensed under an Attribution 4.0 International (CC BY 4.0)

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FTP Download Info

Ftp server:

Ftp username: download_302634

Ftp password: 92811487

The volume of this dataset is bigger than 1 GB. Please use FTP client tools (Filezilla or other else).
Geographic coverage
East: 135.50 West: 73.20
South: 17.80 North: 53.90
  • Temporal resolution: Yearly
  • Spatial resolution: 1km - 10km
  • File size: 1,210 MB
  • Views: 11,564
  • Downloads: 151
  • Access: Open Access
  • Temporal coverage: 1978-12-20 To 2016-02-22
  • Updated time: 2021-04-19
: JIN Rui   LI Xin  

Distributor: National Tibetan Plateau Data Center

Email: data@itpcas.ac.cn

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