Platform Greenhouse Gases Observing Satellite (GOSAT)
Data distributor

Japan Aerospace Exploration Agency (JAXA)
National Institute for Environmental Studies (NIES)
Ministry of the Environment (MOE)


Data product name and description
Distribution disk files
Returned data
Returned file-level metadata
Returned metadata for individual rasters

Data product name and description

Name Description Version
Level 1B+ The CAI L1B+ product is a map-projected radiance product obtained by dividing the CAI L1A product into frames and applying data interpolation and band-to-band registration. First version
Level 1B The CAI L1B product is a radiance product obtained by dividing the CAI L1A product into frames based on band 3 of the TANSO-CAI sensor, and applying band-to-band registration without interpolation. Map projection is not applied. First version

Distribution disk files

File Name File Type Required Contents
GOSATTCAIYYYYMMDDHHmmPPP FFF0_1B1234VAAAA0.h5 ** HDF5 Yes Image data and metadata
** The file name is defined as follows:
  • GOSAT: Fixed; satellite platform name
  • TCAI: Fixed; sensor mode name
  • YYYYMMDDHHmm: Acquisition date and time
  • PPP: Path number
  • FFF: Frame number
  • 1B: Fixed; processing level
  • 1234: Product code
  • VAAAA: Version

Important notes to the user:

  1. The GDB support of GOSAT data products is read-only.
  2. In CATALYST Professional Focus, after selecting the HDF5 file to load the data, you will see a popup window asking which image you want to load. One option is CAI500 and the other is CAI1500; these represent two groups of images with different resolutions. Focus will load the data based on the option you selected.
  3. If you use EASI, Python, or a text-based application, the input file name can have the following formats.
    • Input full path name plus “-CAI500” for an image with a resolution of 500 meters, or “-CAI1500” for an image with a resolution of 1500 meters. For example:
      C:\data\ GOSATTCAI2009042323160410170_1BTRBPV00020.h5-CAI500
      C:\data\ GOSATTCAI2009042323160410170_1BTRBPV00020.h5-CAI1500
    • You can also input the full GDB URI as a file name. For example:

Returned data

Data Product Data Returned Details
GOSAT image data Three raster channels These raster channels represent data set band1Image, band2Image, and band3Image. The rasters are spatially coincident and the ground sample distance of the image data is 500 meters.
GOSAT image data One raster channel This raster channel represents data set band4Image. The ground sample distance of the image data is 1500 meters.
Ephemeris data One binary segment The GDB returns ephemeris data as an orbit segment. This segment includes information about the satellite position, satellite altitude, IFOV, projection, sensor, orbit, and so on.
Geolocation data One ground control point (GCP) segment The geolocation of the image data is returned as a ground control point (GCP) segment. This information is stored as a data set: /Data/geolocation/height, /Data/geolocation/latitude, and /Data/geolocation/longitude. The number of points is number of lines times number of pixels. GDB only chooses 1024 points. The geolocation information allows the image to be accurately tied to particular points on the Earth’s surface.

Returned file-level metadata

GDB imports all metadata stored in the HDF5 file. The metadata shown below has been mapped to GDB metadata.

Name Description Values
MD_ColumnCount Number of pixels per line Integer
MD_RowCount Number of lines per image Integer
MD_NumberOfBands Number of bands per data set Integer
MD_PlatformName Satellite platform name GOSAT
MD_SensorModelName Sensor model name TANSO-CAI or TANSO-FTS
MD_SatelliteAltitude Satellite altitude Float
MD_SourceID Source ID String
MD_Acquisition_DateTime Acquisition date and time String
MD_ProductType Product type CAI L1B+ data
MD_FormatName Format name HDF5
MD_SpatialResolutionX Spatial resolution x Float
MD_SpatialResolutionY Spatial resolution y Float
MD_SatPosition Satellite position Time;X;Y;Z;X’;Y’;Z’...;
MD_SatAttitudes Satellite attitudes Time:roll;pitch;yaw; …;

Returned metadata for individual rasters

GDB imports all attributes attached to each image band as channel metadata.

Name Description Values
unit Unit String, length = variable
validRange Valid range 16-bit unsigned integer array
Range Minimum and maximum pixel values in the frame (except dummy) 16-bit unsigned integer array
dummy Invalid value 16-bit unsigned integer
radianceScale scale 32-bit floating-point
radianceOffset offset 32-bit floating-point


For more information, refer to the GOSAT product format description by the National Institute for Environmental Studies GOSAT Project Office.

© PCI Geomatics Enterprises, Inc.®, 2023. All rights reserved.