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

Description

band1_vis

Band 1 Visible

band2_vis

Band 2 Visible

band3a_vis

Band 3A Visible

band3b_bt

Band 3B Brightness Temperature

band4_vis

Band 4 Brightness Temperature

band5_vis

Band 5 Brightness Temperature

4.5.1. Command Line Arguments

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

4.5.1.1. Frontend Initialization

swath extraction initialization options

--day-fraction

Fraction of day required to produce reflectance products

Default: 0.1

--sza-threshold

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

Default: 100.0

--list-products

List available frontend products

Default: False

4.5.1.2. 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