Global Ocean Remote Sensing Reflectance from ENVISAT MERIS

Remote sensing reflectance (Rrs) data from the ENVISAT MERIS satellite provides the ratio of water-leaving radiance to downwelling irradiance above the ocean surface. This Level-3 global mapped data, version 2022.0, is produced by OB_CLOUD and serves as a foundational observable for deriving oceanographic products. The dataset was last updated in May 2012.

Use Cases

• Deriving chlorophyll-a concentration (chlor_a) from band-specific reflectance values like Rrs_412 and Rrs_443.
• Calculating the diffuse attenuation coefficient at 490 nm (Kd_490) using the suite of Rrs_λ variables.
• Estimating inherent optical properties (IOPs) of water bodies by analyzing spectral reflectance data.
• Monitoring coastal and inland water quality by applying quality flags (land, cloud, sun glint, high aerosol) to filter Rrs data.
• Supporting algorithm development and validation for satellite-based ocean color products.

Strengths

• Provides the foundational observable (Rrs) for retrieving multiple oceanographic products.
• Includes per-file quality flags for land, cloud, sun glint, and high aerosol to aid data filtering.

Limitations

• Data last updated in 2012, making it temporally stale for current analysis.
• Documentation warns of challenges in optically complex coastal and inland waters, indicating potential accuracy limitations in these regions.
• Specific row counts, column counts, and file sizes are unknown, hindering precise resource planning.

Provenance

Source

OB_CLOUD via NASA Earthdata.

Collection Method

Satellite remote sensing from the ENVISAT MERIS instrument.

Time Range

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Freshness

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Geography

Global ocean coverage.