SMMR (1978-1987), SSM / I (1987-2009) and ssmis (2009-2015) daily brightness temperature data are used in this data set, which is generated by double index (TB, 37V, SG) freeze-thaw discrimination algorithm. The classification results include four types: frozen surface, melted surface, desert and water body. The data covers the main part of the Chinese mainland, with a spatial resolution of 25.067525 km. It is stored in asciigrid format in the East grid projection mode.
All ASCII files in the dataset 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 surface freeze-thaw state: 1 for freezing, 2 for melting, 3 for desert, and 4 for precipitation. If you want to display it with a diagram, we recommend using ArcView + 3D or spatial analyst extension module to read it. During the reading process, a file in grid format will be generated, and the displayed grid file is the graphic representation of the ASCII file. Read method:
[1] Add 3D or spatial analyst extension module in ArcView software, and then create a new view
[2] Activate the view, click the file menu, select the import data source option, and the import data source selection box will pop up. Select ASCII raster in the select import file type: box, and the dialog box for selecting source ASCII file will pop up automatically. Click to find any ASCII file in the data set, and then press OK
[3] In the output grid dialog box, type the name of the grid file (it is recommended to use a meaningful file name so that you can view it later) and click the path where the grid file is stored, press OK again, then press Yes (to select integer data), yes (to transfer the generated grid file into the current view). The generated file can be edited according to the grid file standard. This completes the process of displaying ASCII files as grid files.
[4] During batch processing, Arcinfo's ASCII rid command can be used to write AML files, and then run command can be used in grid module to complete:
Usage: ASCIIGRID
The production of this data is supported by NSFC projects: Data Center for environmental and Ecological Sciences in Western China (90502010), land surface data assimilation system research in Western China (90202014), and Research on active and passive microwave radiation transmission simulation and radiation scattering characteristics of permafrost (41071226).
SMMR (1978-1987), SSM / I (1987-2009) and ssmis (2009-2015) daily brightness temperature data
Double index (TB, 37V, SG) freeze-thaw discrimination algorithm
Data set quality control through strict manual audit
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CSTR:11738.11.ncdc.Westdc.2020.634
