Aquarius: 28-Day Sea Surface Density from Satellite Radiometry

Aquarius Level 3 data provides a 28-day running mean of sea surface density at a 1-degree spatial resolution, derived from satellite-measured brightness temperature and backscatter. The dataset is a product of the NASA/CONAE AQUARIUS/SAC-D satellite, which used three radiometers at 1.413 GHz and a scatterometer at 1.26 GHz to retrieve salinity and correct for surface roughness. Surface density is calculated based on the TEOS-10 standard, using retrieved salinity and collocated sea surface temperature from the Reynolds OI product.

Use Cases

• Analyzing seasonal density variations in the global ocean based on 28-day running means.
• Studying ocean circulation and water mass formation using TEOS-10 derived surface density.
• Validating and improving ocean models with satellite-derived, gridded density fields.
• Investigating the relationship between sea surface salinity, temperature, and density from collocated satellite and ancillary data.

Strengths

• Data is derived from a dedicated satellite instrument with three radiometers providing a 370 km swath and specific beam footprints (e.g., 76x94 km).
• Uses the internationally recognized TEOS-10 standard for calculating seawater properties.
• Provides a consistently processed, gridded Level 3 product at a defined 1-degree resolution.

Limitations

• Metadata completeness is low; specific column names, row counts, and data volume are unknown across all sources.
• A conflict exists in 'last updated' dates, with one source showing 2026 (likely an error or placeholder) and another showing 2015, casting doubt on data freshness.
• The dataset is limited to descending satellite passes only, which may introduce sampling biases.

Provenance

Source

National Aeronautics and Space Administration (NASA) and Comision Nacional de Actividades Espaciales (CONAE)

Collection Method

Satellite remote sensing via the AQUARIUS/SAC-D spacecraft's L-band radiometers and scatterometer.

Time Range

Temporal coverage is not explicitly stated, but data is averaged over daily, 7-day, monthly, and seasonal scales.

Freshness

Last updated dates conflict: 2026-03-13 (datagov, likely erroneous) and 2015-06-07 (nasa_earthdata).

Geography

Global ocean coverage.