Aqua MODIS PAR: Global Ocean Photosynthetically Available Radiation

NASA's Aqua MODIS Level-3 PAR data suite provides satellite-based estimates of downwelling solar radiation in the 400–700 nm range available for photosynthesis at the ocean surface. The data quantifies daily or instantaneous usable light energy in moles of photons per square meter. It is used to estimate marine primary production, interpret phytoplankton bloom dynamics, and support ecosystem models.

Use Cases

• Estimate marine primary production based on daily photosynthetically available radiation (PAR).
• Interpret phytoplankton bloom dynamics based on satellite-derived light availability.
• Provide context for in-situ optical and biogeochemical measurements based on surface PAR estimates.
• Support ecosystem and biogeochemical models with input data on biologically usable light energy.

Strengths

• Data is derived from the MODIS instrument on NASA's Aqua satellite, a well-established scientific sensor.
• The product quantifies a specific geophysical variable (PAR) in a standard scientific unit (mol photons m⁻² d⁻¹).
• The description indicates the data is widely used for primary production estimation and ecosystem modeling.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count and file size are unknown, which may limit suitability assessment.
• Data may reflect the spatial and temporal coverage bias inherent to satellite remote sensing from a single platform.

Provenance

Source

NASA Earthdata (OB_CLOUD)

Collection Method

Satellite remote sensing data from the MODIS instrument on the Aqua satellite, processed to Level-3 global mapped products.

Geography

Global ocean surface