Sentinel-3A OLCI Level-3: Global Mapped Ocean Remote-Sensing Reflectance (NRT)

Near real-time (NRT) global mapped remote-sensing reflectance (RRS) data from the Sentinel-3A OLCI instrument, version 2022.0. The Ocean Biology DAAC produces these products using the best-available ancillary meteorological and ozone data for a snapshot within a single orbit. This foundational observable supports the retrieval of ocean color products like chlorophyll-a concentration and supports algorithm development and water-quality applications.

Use Cases

• Retrieving chlorophyll-a concentration (chlor_a) based on remote-sensing reflectance (RRS) data.
• Calculating the diffuse attenuation coefficient (Kd_490) for water clarity based on RRS spectral bands.
• Deriving inherent optical properties (IOPs) of water bodies from the foundational RRS observable.
• Monitoring coastal and inland water quality by analyzing RRS values after applying quality flags for clouds and aerosols.
• Validating and developing ocean color algorithms using the near real-time RRS data stream.

Strengths

• Provides near real-time (NRT) data snapshots from the Sentinel-3A satellite.
• Includes per-file quality flags for land, cloud, sun glint, and high aerosol conditions.
• The RRS variable is described as the foundational observable for retrieving multiple ocean biogeochemical products.

Limitations

• Row count and file size are unknown, which may limit suitability assessment.
• Column-level documentation is absent; field semantics must be inferred after download.
• The description notes NRT products use less-than-optimal ancillary data and calibration compared to final products.

Provenance

Source

Ocean Biology DAAC (OB_CLOUD) via NASA Earthdata.

Collection Method

Satellite remote sensing from the Sentinel-3A Ocean and Land Colour Instrument (OLCI).

Freshness

Near real-time (NRT); specific last update date is unknown.

Geography

Global