SWOT Prelaunch PIES: Ocean Bottom Pressure and Travel Time Measurements

Approximately 300 kilometers west of Monterey, California, a Pressure-sensing Inverted Echo Sounder (PIES) collected in-situ data from September 2019 to January 2020. This dataset contains bottom pressure and round-trip acoustic travel time measurements, part of a broader prelaunch campaign to validate instruments for the SWOT satellite mission. The data can be used to derive steric height and assess oceanographic conditions at a key calibration site.

Use Cases

• Validating SWOT satellite altimetry data using in-situ bottom pressure and travel time measurements.
• Deriving equivalent steric height through regression analysis of acoustic travel time.
• Assessing oceanographic conditions and instrument performance at a designated Cal/Val crossover location.
• Comparing PIES measurements with concurrent data from CTD moorings and gliders deployed in the same campaign.

Strengths

• Data is part of a coordinated, multi-instrument field campaign designed for satellite Cal/Val.
• Provides a specific 5-month time series (Sep 2019 - Jan 2020) from a defined geographic location.
• Cross-platform presence on government data portals indicates formal curation and importance.

Limitations

• Column names and exact data structure are not provided in the available metadata.
• There is a conflict in the 'last updated' metadata, with dates ranging from 2020 to 2026.
• The license is ambiguously listed as 'other-license-specified' without explicit terms.

Provenance

Source

National Aeronautics and Space Administration

Collection Method

Deployed via a Pressure-sensing Inverted Echo Sounder (PIES) instrument on the seafloor.

Time Range

September 2019 to January 2020

Freshness

2026-04 09

Geography

Approximately 300 km west of Monterey, California, USA, near the SWOT CalVal crossover location.