Global Ocean Microplastic Concentration Maps from CYGNSS Satellite Constellation

NASA's CYGNSS constellation provides daily gridded maps of ocean microplastic number density. The dataset is produced by the University of Michigan CYGNSS Science Team using an empirical relationship between ocean surface roughness and wind speed derived from satellite measurements. Version 3.2 uses updated Level 1 scattering cross section data and algorithm parameterizations.

Use Cases

• Mapping daily microplastic number density (#/km^2) on a 0.25-degree latitude/longitude grid to identify pollution hotspots.
• Analyzing temporal trends in microplastic concentration using the 30-day, 1-degree feature resolution data for seasonal or annual studies.
• Correlating Mean Square Slope (MSS) anomaly data with independent factors like algal blooms or oil spills to validate the retrieval algorithm.
• Assessing the impact of anomalous atmospheric conditions, such as within the Intertropical Convergence Zone, on microplastic concentration estimates.

Strengths

• Data is derived from a constellation of eight micro-satellites providing nearly gap-free Earth coverage.
• Offers a mean revisit time of seven hours and a median revisit time of three hours for frequent observation.
• Provides data on a daily temporal grid with 0.25-degree spatial resolution for detailed mapping.

Limitations

• Microplastic concentration is indirectly estimated via an empirical model, not direct measurement, introducing potential retrieval errors.
• Estimates are unreliable in regions with non-correlative factors affecting ocean roughness, such as areas with biogenic surfactants or oil spills.
• The dataset's accuracy is constrained by the binning and spatial-temporal averaging of the MSS anomaly.

Provenance

Source

CYGNSS Science Team, University of Michigan, via NASA Earth System Science Pathfinder Mission.

Collection Method

Microplastic concentration is indirectly estimated from an empirical relationship between CYGNSS-measured ocean surface roughness and wind speed.

Time Range

Data collection began after the CYGNSS launch on 15 December 2016; specific coverage period for Version 3.2 is unknown.

Freshness

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Geography

Global ocean coverage, with an orbital inclination of approximately 35° from the equator.