4.5. AVHRR Reader

The AVHRR reader is for reading AAPP L1B files for the AVHRR instrument. These files are a custom binary format. The reader can be specified with the polar2grid.sh command using the avhrr frontend name.

This reader’s default resampling algorithm is ewa for Elliptical Weighted Averaging resampling. The --fornav-D option is set to 10 and --fornav-d is set to 1.

The AVHRR reader provides the following products:

Product Name



Band 1 Visible


Band 2 Visible


Band 3A Visible


Band 3B Brightness Temperature


Band 4 Brightness Temperature


Band 5 Brightness Temperature

4.5.1. Command Line Arguments

usage: polar2grid.sh avhrr <writer> [-h] [--day-fraction DAY_FRACTION]
                                    [--sza-threshold SZA_THRESHOLD]
                                    [-p [PRODUCTS [PRODUCTS ...]]] Frontend Initialization

swath extraction initialization options


Fraction of day required to produce reflectance products

Default: 0.1


Angle threshold of solar zenith angle used when deciding day or night

Default: 100.0


List available frontend products

Default: False Frontend Swath Extraction

swath extraction options

-p, --products

Specify frontend products to process

4.5.2. Execution Examples

polar2grid.sh avhrr scmi --list-products -f /l1b/hrpt_noaa18_20170202_2242_60321.l1b

polar2grid.sh avhrr gtiff -f ../input/hrpt_M01_20170202_0227_22708.l1b

polar2grid.sh avhrr gtiff -p band1_vis band4_bt -f /data/hrpt_noaa19_20170202_2042_41144.l1b

polar2grid.sh avhrr scmi -p band3a_vis -g lcc_conus_1km --sector-id LCC --letters --compress -f hrpt_M01_20170202_1457_22716.l1b

polar2grid.sh avhrr scmi --grid-coverage=0 -g polar_alaska_1km --sector-id Polar --letters --compress -f /avhrr

polar2grid.sh avhrr hdf5 --add-geolocation --grid-configs /home/avhrr/grids/local_grid.conf -g my_grid  -f ../input/hrpt_*.l1b

polar2grid.sh avhrr binary -p band1_vis band4_bt -g lcc_eu -f /data/avhrr/metoba