NOAA-21 VIIRS: Global Mapped Ocean Light Attenuation (KD) Near Real-Time Data

Satellite-derived global maps of the diffuse attenuation coefficient for downwelling irradiance (KD), a measure of ocean water clarity. The data is produced by the NASA Ocean Biology DAAC using NOAA-21 VIIRS sensor data and near real-time ancillary inputs. This version, R2022.0, provides quicklook snapshots from within single orbits, with data last updated on 2026-03 13.

Use Cases

• Monitor near real-time changes in coastal water clarity based on the KD parameter.
• Model primary productivity in ocean ecosystems based on light penetration data.
• Assess spatial patterns of ocean turbidity and particulate matter from satellite-derived maps.
• Validate hydrodynamic or biogeochemical models using global, satellite-based KD observations.

Strengths

• Data is produced by NASA's Ocean Biology DAAC, an authoritative source for ocean color data.
• Provides near real-time (NRT) quicklook products for timely analysis.
• Offers global spatial coverage from the NOAA-21 VIIRS satellite sensor.

Limitations

• Description metadata is limited; actual data quality requires manual inspection after download.
• Quicklook products use less-than-optimal ancillary and calibration data, as stated in the description.
• Row count and specific data format details are unknown, which may limit suitability assessment.

Provenance

Source

National Aeronautics and Space Administration (NASA) Ocean Biology DAAC

Collection Method

Satellite remote sensing data from the NOAA-21 VIIRS sensor, processed with near real-time ancillary meteorological and ozone data.

Time Range

Near real-time, providing snapshots from within single orbits.

Freshness

Last updated 2026-03-13 20:22:44.669816; freshness should be verified.

Geography

Global