TOPEX/POSEIDON GDR: Ocean Altimetry Measurements

Over a hundred parameters per second are recorded in this global altimeter dataset from the TOPEX/POSEIDON mission launched in August 1992. The data provides sea surface height measurements with a precision of 3 cm and accuracy of 13 cm, alongside significant wave height, ionospheric corrections, and tides. Files are arranged in 10-day cycles separated into 254 passes, each approximately 56 minutes long.

Use Cases

• Monitoring sea level rise based on precise sea surface height measurements.
• Analyzing ocean wave conditions using significant wave height data.
• Studying ionospheric effects on satellite signals via the ionospheric correction parameter.
• Investigating tidal patterns and ocean topography from the geophysical corrections.
• Calibrating modern altimeter missions using the foundational dual-frequency (Ku and C band) measurements.

Strengths

• Provides high-precision measurements with sea surface height precision of 3 cm and accuracy of 13 cm.
• Contains data from two distinct altimeters: a NASA dual-frequency instrument and a CNES solid-state Ku-band proof-of-concept instrument.
• Offers global coverage and a structured temporal organization in 10-day cycles with 254 passes.

Limitations

• The dataset is described as research data requiring user-provided analysis software and calculation of anomalies.
• Metadata completeness is low; specific column names, row counts, and file sizes are unknown across all sources.
• A conflict exists in freshness metadata, with one source listing an update in 2005 and others in 2026.

Provenance

Source

NASA and French space agency (CNES) via the TOPEX/POSEIDON mission.

Collection Method

Satellite altimetry measurements from two instruments.

Time Range

Mission launched in August 1992; specific data collection period not provided.

Freshness

2026-04-09 21:30:54.956592

Geography

Global coverage.