4.6. 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

4.6.1. 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 --rescale-configs $POLAR2GRID_HOME/rescale_configs/amsr2_png.ini flag when generating AMSR2 L1B GeoTIFFs. 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 Add Overlays (Borders, Coastlines, Grids Lines, Rivers) and Add Colormap documentation for more information on generating these NRL-like PNGs.

4.6.2. Command Line Arguments

usage: polar2grid.sh amsr2_l1b <writer> [-h] [--list-products]
                                        [-p PRODUCTS [PRODUCTS ...]]

4.6.2.1. Frontend Initialization

swath extraction initialization options

--list-products

List available frontend products and exit

Default: False

4.6.2.2. Frontend Swath Extraction

swath extraction options

-p, --products

Specify frontend products to process

Examples:

 polar2grid.sh amsr2_l1b gtiff -h

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

 polar2grid.sh amsr2_l1b gtiff -g lcc_fit -f ../data/GW1AM2_201607201808_128A_L1DLBTBR_1110110.h5

 polar2grid.sh amsr2_l1b gtiff --rescale-configs $POLAR2GRID_HOME/rescale_configs/amsr2_png.ini -g lcc_fit -f ../data/GW1AM2_201607191903_137A_L1DLBTBR_1110110.h5

 polar2grid.sh amsr2_l1b scmi --list-products -f /amsr2/GW1AM2_201607201808_128A_L1DLBTBR_1110110.h5

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