Global Ocean Photosynthetically Available Radiation Satellite Estimates

Near real-time satellite data provides global estimates of downwelling solar radiation in the 400–700 nm range available for photosynthesis at the ocean surface. The dataset includes daily (par) and instantaneous (ipar) photosynthetically available radiation, measured in moles of photons per square meter. It is produced by OB_CLOUD and is based on NOAA-21 VIIRS satellite observations.

Use Cases

• Estimate daily marine primary production by integrating the daily PAR (par) variable over time and space.
• Analyze phytoplankton bloom dynamics by correlating instantaneous PAR (ipar) measurements with concurrent biological observations.
• Interpret optical and biogeochemical measurements by using the par and ipar fields as contextual light availability data.
• Validate and force ecosystem models by ingesting the Level-2 processing flags (l2_flags) to filter data quality.

Strengths

• Provides global spatial coverage of ocean surface PAR.
• Includes both daily integrated (par) and instantaneous (ipar) radiation measurements for temporal analysis.
• Near real-time (NRT) data delivery supports timely research and monitoring.

Limitations

• Precise temporal coverage, row count, and sample size are unknown from the input.
• Data quality is contingent on satellite sensor performance and atmospheric conditions, as indicated by the l2_flags bitmask.

Provenance

Source

NOAA-21 VIIRS satellite, processed by OB_CLOUD and distributed via NASA Earthdata.

Collection Method

Satellite-based remote sensing estimates.

Time Range

Near real-time; specific start date unknown.

Freshness

Near real-time.

Geography

Global ocean coverage.