4.5. AMSR2 L1B Reader

AMSR2 L1B files contain various parameters from the GCOM-W1 AMSR2 instrument.

This reader can be used by specifying the reader name amsr2_l1b to the polar2grid.sh script. Supported files usually have the following naming scheme:

GW1AM2_201607201808_128A_L1DLBTBR_1110110.h5

This reader’s default remapping algorithm is nearest for nearest neighbor resampling due to the instruments scan pattern and swath shape. The --distance_upper_bound flag defaults to 12.

Currently this reader provides only the following datasets:

Product Name	Description
btemp_36.5v	Brightness Temperature 36.5GHz Polarization Vertical
btemp_36.5h	Brightness Temperature 36.5GHz Polarization Horizontal
btemp_89.0av	Brightness Temperature 89.0GHz A Polarization Vertical
btemp_89.0ah	Brightness Temperature 89.0GHz A Polarization Horizontal
btemp_89.0bv	Brightness Temperature 89.0GHz B Polarization Vertical
btemp_89.0bh	Brightness Temperature 89.0GHz B Polarization Horizontal

4.5.1. Special AMSR2 Naval Research Lab (NRL) PNG Scaling

A common use case for the AMSR2 L1B reader is to generate PNG images similar to those generated by the U.S. Naval Research Lab (NRL) with a colormap and coastlines. This requires using an alternate non-default scaling configuration provided in the tarball. It can be used by providing the --extra-config-path $POLAR2GRID_HOME/example_enhancements/amsr2_png flag when generating AMSR2 L1B GeoTIFFs. This allows the scaling provided in the $POLAR2GRID_HOME/example_enhancements/amsr2_png/enhancements/generic.yaml file to be used. Once this rescaling has been done, colormap files can be found in $POLAR2GRID_HOME/colormaps which can then be applied using the the add_colormap.sh script.

See the example section Creating AMSR2 Reprojections for more information on generating these NRL-like PNGs.

4.5.2. Command Line Arguments

usage: polar2grid.sh -r amsr2_l1b -w <writer> [-h]

Examples:

polar2grid.sh -r amsr2_l1b -w geotiff --list-products-all -f ../data/*L1DLBTBR*.h5

polar2grid.sh -r amsr2_l1b -w geotiff  -f <path to files>/<AMSR2 Level 1B filename>

polar2grid.sh -r amsr2_l1b -w geotiff -g lcc_fit --fill-value 0 -f ../data/GW1AM2_202209121053_051D_L1DLBTBR_1110110.h5

polar2grid.sh -r amsr2_l1b -w geotiff --extra-config-path $POLAR2GRID_HOME/example_enhancements/amsr2_png --fill-value 0 -f ../gcom_data/

polar2grid.sh -r amsr2_l1b -w awips_tiled --list-products -f /amsr2/GW1AM2_202209120729_019D_L1DLBTBR_2220220.h5

polar2grid.sh -r amsr2_l1b -w awips_tiled -g lcc_conus_1km -p btemp_36.5h btemp_89.0av --sector-id LCC --letters --compress -f GW1AM2_201607191903_137A_L1DLBTBR_1110110.h5