The NASA Jet Propulsion Laboratory and NASA Earthdata have released the newest version of Orbiting Carbon Observatory (OCO) Absorption Coefficients (ABSCO) tables, version 5.2. These ABSCO tables were previously only available by request. Due to their popularity among the user and academic communities, the tables have now been made publicly available.
The ABSCO tables are lookup tables that supply cross-section values for absorbing gases in the Level 2 algorithm (L2) retrieval process. They record molecular absorption cross-sections of O2, H2O, and CO2 gases over the range of relevant wavelengths, temperatures, and pressures in units of cm2/molecule. During the L2 generation process, the retrieval algorithm computes atmospheric absorption at each relevant temperature, pressure, and wavelength using linear interpolation.
The v5.2 ABSCO tables are used in the Level 2 algorithms for the Orbiting Carbon Observatory missions (OCO-2 and OCO-3) for all version 11 (v11) point builds. The v5.2 ABSCO tables are also used as input to the Atmospheric Carbon Observations from Space for the Greenhouse Gas Observing Satellite (ACOS-GOSAT) v11 Level 2 algorithm. Each version of the OCO-2/3 or ACOS-GOSAT Level 2 algorithm utilizes a specific ABSCO table version.
It is recommended that users adopt the most recent tables, ABSCO v5.2, which are available from the Goddard Earth Sciences Data and Information Services Center (GES DISC). The OCO ABSCO Data User Guide provides further information on the ABSCO tables and their use is also available from GES DISC.