Sentinel-3B OLCI Level-2 Inherent Optical Properties for Ocean Water

The Ocean Biology DAAC produces near real-time (NRT) Inherent Optical Properties (IOP) data from the Sentinel-3B OLCI instrument. This dataset provides per-pixel inherent optical properties, including total absorption and backscattering coefficients, derived from spectral Remote Sensing Reflectance using the Generalized Inherent Optical Properties (GIOP) model framework. The activity was informed by the Satellite Needs Working Group (SNWG), an interagency effort of the U.S. Government.

Use Cases

• Water-type classification based on inherent optical properties like absorption and backscattering coefficients.
• Water-clarity assessment using the particulate backscattering coefficient (bbp_443).
• Biogeochemical studies leveraging phytoplankton absorption coefficient (aph_443) and CDOM/detritus absorption (adg_443).
• Cross-sensor comparisons enabled by the inherent optical properties, which are more robust than apparent optical products.

Strengths

• Provides near real-time (NRT) data, offering a snapshot of ocean conditions within a single orbit.
• Includes uncertainty estimates for key variables like aph_unc_443, adg_unc_443, and bbp_unc_443.
• Supports multiple applications including water-type classification, clarity assessment, and biogeochemical studies as described.

Limitations

• Description metadata is limited; actual data quality requires manual inspection after download.
• The NRT processing uses less-than-optimal ancillary data and calibration, as stated in the description.
• Row count and file formats are unknown, which may limit suitability assessment.

Provenance

Source

Ocean Biology DAAC (OB_CLOUD) via NASA Earthdata.

Collection Method

Derived from Sentinel-3B OLCI Level-2 Regional Earth-observation Full Resolution (EFR) data using the Generalized Inherent Optical Properties (GIOP) model framework.

Freshness

Near real-time (NRT); version 2022.0.

Geography

Global ocean coverage from Sentinel-3B orbit.