NOAA-21 VIIRS: Global Ocean Remote-Sensing Reflectance (RRS) Near Real-time Data

NOAA-21 VIIRS Level-3 Global Binned Remote-Sensing Reflectance (RRS) - Near Real-time (NRT) Data, version 2025.0, is produced by the Ocean Biology DAAC (OB_CLOUD). It provides a snapshot of remote-sensing reflectance data from a single orbit, used as a foundational observable for retrieving ocean color products. The data is processed using the best-available ancillary meteorological and ozone data, though inputs and calibration are noted as less than optimal.

Use Cases

• Retrieving chlorophyll-a concentration (chlor_a) based on remote-sensing reflectance (Rrs) data.
• Estimating the diffuse attenuation coefficient at 490 nm (Kd_490) for water clarity studies based on Rrs values.
• Deriving inherent optical properties (IOPs) of water bodies using the foundational Rrs observable.
• Developing and validating ocean color algorithms based on the near real-time reflectance data.
• Monitoring coastal and inland water quality by analyzing Rrs data, with attention to quality flags for complex waters.

Strengths

• Data is produced in near real-time (NRT), providing a snapshot from a single orbit.
• The dataset is versioned (2025.0), indicating a managed release process.
• Includes per-file quality flags for land, cloud, sun glint, and high aerosol, as mentioned in the description.

Limitations

• The description notes inputs and calibration are 'less than optimal' for these near real-time products.
• Row count, column definitions, and file formats are unknown, limiting suitability assessment.
• Last update date is unknown; freshness unverified.

Provenance

Source

Ocean Biology DAAC (OB_CLOUD), via NASA Earthdata (nasa_earthdata).

Collection Method

Satellite remote sensing from the NOAA-21 VIIRS instrument, processed into Level-3 binned products.

Freshness

Near real-time (NRT)

Geography

Global