Global Ocean Photosynthetically Available Radiation from MODIS Satellite

Satellite-based estimates of downwelling solar radiation in the 400–700 nm range available for photosynthesis at the ocean surface. The data suite quantifies daily or instantaneous usable light energy, expressed in moles of photons per square meter. It is produced by OB_CLOUD using NASA MODIS NRT data, with a version designation of 2022.0.

Use Cases

• Estimate daily marine primary production by integrating the 'par' variable over time and space.
• Interpret phytoplankton bloom dynamics by analyzing spatial and temporal patterns in the 'par' and 'ipar' fields.
• Provide environmental context for in-situ optical and biogeochemical measurements by collocating them with satellite 'par' estimates.
• Initialize and validate light–biology interaction modules in ecosystem models using the 'par' geophysical variable.

Strengths

• Provides global spatial coverage of ocean surface PAR.
• Includes both daily ('par') and instantaneous ('ipar') radiation estimates.
• Data is designated as Near Real-time (NRT), supporting timely analysis.

Limitations

• Specific temporal coverage, row count, and spatial resolution are not provided in the input.
• Relies on satellite sensor data which can be affected by cloud cover and atmospheric conditions.
• The 'l2_flags' bitmask requires interpretation using provided attributes to understand data quality.

Provenance

Source

NASA Earthdata (Aqua MODIS satellite).

Collection Method

Satellite remote sensing, processed to Level-3 global mapped products.

Freshness

Near Real-time (NRT)

Geography

Global ocean coverage.