The freeze/thaw status of the near-surface soil is the water-ice phase transition that occurred at the top soil layer. It is an important indicator as a giant on-off “switch” of the land surface processes including water, energy, and carbon exchanges between the land surface and atmosphere. The freeze/thaw status is an essential variable for understanding how the ecosystem responds to and affects global changes. This dataset is based on the AMSR-E and AMSR2 passive microwave brightness temperature data, and the freeze-thaw discriminant function algorithm is used to generate the global near-surface soil freeze-thaw status with a spatial resolution of grids at 0.25° from 2002 to 2019. The dataset can be used for the analysis of the spatial distribution and trend changes of global freeze-thaw cycles, such as the freeze/thaw onset dates and duration. It provides data support for understanding the interaction mechanism between the land surface freeze-thaw cycle and the land-atmosphere exchanges under the context of global changes.

File naming and required software

The file name is to be of the following structure:
XXXX_YYYYMMDD_PP_LL.h5
Each of the elements is as follows:
XXXX: 4 characters, Name of satellite sensor (AMSR represents AMSR-E or AMSR2)
YYYY: 4 characters, Year
MM: 2 characters, Month
DD: 2 characters, Day
PP: 2 characters, Name of the product (FT represents freeze/thaw status)
RR: 2 characters, Spatial resolution of data grids (0.25°)

Example: AMSR_20070125_FT_25.h5 represents the AMSR-E/2 sensors derived near-surface freeze-thaw status on January 25, 2007 with the grid spatial resolution at 0.25 degree.

Data Citations Data citation guideline What's data citation?

Cite as:

Zhao, T. (2018). 2002-2019 Global AMSR-E/2 Near-surface Freeze/Thaw state (0.25°). A Big Earth Data Platform for Three Poles, DOI: 10.11888/Glacio.tpdc.270890. CSTR: 18406.11.Glacio.tpdc.270890. (Download the reference： RIS | Bibtex )

Related Literatures:

1. Zhao TJ, Zhang LX, Jiang LM, Zhao SJ, Chai LN, Jin R. A new soil freeze thaw discriminant algorithm using AMSR-E passive microwave imagery. Hydrological Processes, 2011, 25(11): 1704-1716. DOI: 10.1002/hyp.7930.( View Details | Download | Bibtex)

2. Wang P K, Zhao T J, Shi J C, et al. Parameterization of the freeze/thaw discriminant function algorithm using dense in-situ observation network data[J]. Int. J. Digit. Earth, 2019, 12(8): 980-994.( View Details | Bibtex)

3. Hu T, Zhao T, Zhao K, et al. A continuous global record of near-surface soil freeze/thaw status from AMSR-E and AMSR2 data[J]. International Journal of Remote Sensing, 2019, 40(18): 6993-7016.( View Details | Bibtex)

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

Support Program

CASEarth:Big Earth Data for Three Poles（grant No. XDA19070000） (No:XDA19000000)

o Strategic Priority ResearchProgram of the Chinese Academy of Sciences: Grant No. XDA19070204 (No:XDA19070204) [XDA19070204]

Copyright & License

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