Tips for working with AMSR-E Daily Soil Moisture data

Soil moisture is a key variable in understanding land surface hydrology and in modeling ecosystems, weather, and climate. Among NSIDC’s most popular data sets is the “AMSR-E/Aqua Daily L3 Surface Soil Moisture, Interpretive Parameters, & QC EASE-Grids” (AE_Land3) data set. This data set is distributed in HDF-EOS format and one of the biggest hurdles encountered by many users is simply learning how to display the data. Here are some tips on how to get started.

The HDF Group provides sample code for access and visualization of HDF data into IDL, MATLAB, and NCL. Access to the sample code for AMSR-E HDF data is provided on the HDF Group’s HDF-EOS Comprehensive Examples Web page.

If you are more familiar with GeoTIFF format, you may choose to utilize the HDF-EOS to GeoTIFF (HEG) Tool to convert AMSR-E Daily Soil Moisture HDF data into GeoTIFF format. This tool also allows you to subset the data with spatial or parameter constraints, as well as change the output projection. These HEG Tool services are also available as an option when ordering these data through the Reverb search and order interface. Instructions on how to use these data services in Reverb can be found in this Online Support article.

If you are interested in importing the data into ArcGIS, you can either use the GeoTIFF files generated by the HEG Tool or downloaded from Reverb, or you can perform a few steps to import the native HDF-EOS files into ArcMap. Using the ArcToolbox, you can easily extract a data field from an HDF file and save it in a different raster format that you are more familiar with. Instructions detailing how to do this can be found in this Online Support article.

AMSR-E L3 Daily Soil Moisture plot, 07/01/2002

AMSR-E L3 Daily Soil Moisture plot, 07/01/2002.

Tips for working with NSIDC’s most popular sea ice concentration data

NSIDC’s sea ice concentration data are used by scientists and students, journalists and advisers. The range of possible uses for the data is as varied as the data users themselves. The biggest hurdle encountered by many users is simply learning how to initially read and display the data. Here are some tips on how to get started.

The “Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS Passive Microwave Data” are distributed in gridded binary format. NSIDC provides IDL routines to ingest and read the data. These tools can be found at the Polar Stereographic Tools Web page.

However, if you are unfamiliar with IDL, there are other options that you can use. First of all, you may be interested in downloading the data via the Polaris search and order interface. This Web tool allows you to download the data in GeoTIFF or NetCDF formats. It also allows you to make spatial and temporal constraints on the data as well as change the output projection.

If you are interested in importing the data to ArcGIS, you can either use the GeoTIFF files downloaded from Polaris (see above), or you can perform a few steps to import the native binary files. In order to do this, you will need to rename the files, create a header file for the data, and use ArcToolbox to transform the files to a different format. Instructions detailing how to do this can be found in this Online Support article.

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