4.6. AHI HimawariCast (HRIT) Reader

The AHI High Rate Information Transmission (HRIT) Reader operates on standard Japan Meteorological Agency (JMA) Himawari-8 and Himawari-9 Advanced Himawari Imager (AHI) HRIT Digital Video Broadcast (DVB) HimawariCast files. This broadcast consists of a subset of 14 bands at reduced spatial resolution. The AHI HRIT reader works off of the input filenames to determine if a file is supported by Geo2Grid. Files usually have the following naming scheme:

IMG_DK01B04_201809100300

These are the mission compliant radiance file naming conventions used by JMA. The AHI HRIT reader supports a subset of instrument spectral bands, identified in Geo2Grid as the products shown in the table below. The AHI HRIT reader can be provided to the main geo2grid.sh script using the -r option and the reader name ahi_hrit.

The list of supported products includes natural color imagery. This is created by means of a python based atmospheric Rayleigh scattering correction algorithm that is executed as part of the Geo2Grid AHI HRIT reader, along with sharpening to the highest spatial resolution.

Please note that true color image RGB creation is not supported for HimawariCast because AHI Band 1 (Blue) and Band 2 (Green) are not included.

For more information on the creation of RGBs, please see the RGB section.

Product Name	Description
B03	Channel 3 (0.64um) Reflectance Band
B04	Channel 4 (0.86um) Reflectance Band
B05	Channel 5 (1.6um) Reflectance Band
B06	Channel 6 (2.3um) Reflectance Band
B07	Channel 7 (3.9um) Brightness Temperature Band
B08	Channel 8 (6.2um) Brightness Temperature Band
B09	Channel 9 (6.9um) Brightness Temperature Band
B10	Channel 10 (7.3um) Brightness Temperature Band
B11	Channel 11 (8.6um) Brightness Temperature Band
B12	Channel 12 (9.6um) Brightness Temperature Band
B13	Channel 13 (10.4um) Brightness Temperature Band
B14	Channel 14 (11.2um) Brightness Temperature Band
B15	Channel 15 (12.4um) Brightness Temperature Band
B16	Channel 16 (13.3um) Brightness Temperature Band
natural_color	Ratio sharpened rayleigh corrected natural color
airmass	Air mass RGB
ash	Ash RGB
dust	Dust RGB
fog	Fog RGB
night_microphysics	Night Microphysics RGB

4.6.1. Command Line Usage

usage: geo2grid.sh -r ahi_hrit -w <writer> [-h]

Examples:

geo2grid.sh -r ahi_hrit -h

geo2grid.sh -r ahi_hrit -w geotiff --list-products -f /ahi8/hcast/2330

geo2grid.sh -r ahi_hrit -w geotiff -f /ahi8/hcast/IMG_DK01IR4_201811122330

geo2grid.sh -r ahi_hrit -w geotiff -p B03 B04 B05 B06 B16 natural_color --num-workers 8 -f /hrit/ahi/

geo2grid.sh -r ahi_hrit -w geotiff --ll-bbox 125 -15 160 10 -f /data/IMG_DK01*