Global Satellite Estimates of Photosynthetically Available Radiation for Ocean Surface

Satellite-based estimates of downwelling solar radiation in the 400–700 nm range available for photosynthesis at the ocean surface. Data quantifies daily and instantaneous usable light energy in moles of photons per square meter. The product is provided by NASA's OB_CLOUD organization and is identified as version 2022.0.

Use Cases

• Estimate marine primary production rates using the daily 'par' variable.
• Interpret phytoplankton bloom dynamics by analyzing spatial and temporal patterns in the 'ipar' (instantaneous) data.
• Provide environmental context for in-situ optical and biogeochemical measurements by correlating them with satellite-derived 'par' values.
• Support ecosystem models by integrating the 'par' and 'ipar' geophysical variables as light availability inputs.
• Filter data quality for analysis using the 'l2_flags' bitmask variable to identify reliable pixels.

Strengths

• Provides global spatial coverage of ocean surface light availability.
• Includes both daily ('par') and instantaneous ('ipar') radiation estimates for temporal analysis.
• Data is processed to Level-3 binned format, indicating aggregation and quality control.

Limitations

• Specific row count, temporal range, and spatial resolution are unknown from the input.
• Relies on satellite sensor data which can be affected by cloud cover and atmospheric conditions.
• The 'l2_flags' bitmask requires interpretation of per-variable attributes for correct use.

Provenance

Source

NASA Earthdata (OB_CLOUD), derived from NOAA-20 VIIRS satellite sensor.

Collection Method

Satellite remote sensing data processed to Level-3 binned geophysical products.

Time Range

null

Freshness

Described as Near Real-time (NRT) data, implying frequent updates, but specific frequency is null.

Geography

Global ocean coverage.