PACE OCI Level-2 Regional Ocean Color Inherent Optical Properties (OC_IOP) Data, version 3.2

The Inherent Optical Properties (IOP) suite provides per-pixel inherent optical properties - quantities that describe how seawater and its constituents absorb and scatter light, independent of illumination or viewing geometry. IOPs are retrieved from spectral Remote Sensing Reflectance (Rrs) using the default configuration of the Generalized Inherent Optical Properties (GIOP) model framework. These products support water-type classification, water-clarity assessment, biogeochemical studies, and forward/adjoint radiative-transfer applications, and they enable more robust cross-sensor comparisons than purely apparent (AOP) products.

The hyperspctral band list is found in the science data file metadata.

Geophysical variables in this suite include:
- Kd - Diffuse attenuation coefficient of downwelling irradiance (m^-1)
- a - Total absorption coefficient (sum of pure water + phytoplankton + CDOM/detritus, m^-1)
- bb - Total backscattering coefficient (m^-1)
- aph - Phytoplankton absorption coefficient (m^-1)
- aph_unc_442 - Uncertainty in absorption due to phytoplankton at 442 nm (m^-1)
- adg_442 - Combined CDOM + non-algal detritus absorption coefficient at 442nm (m^-1)
- adg_unc_442 - Uncertainty in absorption due to gelbstoff and detrital material at 442 nm (m^-1)
- bbp_442 - Particulate backscattering coefficient at 442nm (m^-1)
- bbp_unc_442 - Uncertainty in particulate backscattering at 442 nm (m^-1)
- rrsdiff - Fractional mean Rrs difference (reconstructed from inverted IOPs - input) (unitless)
- l2_flags - Level-2 processing flags (bitmask; see per-variable attributes for flag_masks and flag_meanings)