SWOT Radiometer IGDR: Atmospheric Water and Ocean Surface Data

SWOT satellite data provides global measurements of atmospheric water vapor, cloud liquid water, and wind speed to correct altimeter range delays. The dataset consists of discrete measurements along two tracks approximately 30 km from the satellite nadir, processed from brightness temperatures at 18.7, 23.8, and 34 GHz. It is distributed as one netCDF4 file per half-orbit with a nominal latency of less than 1.5 days.

Use Cases

• Correcting altimeter range delays for ocean topography based on estimated wet troposphere content.
• Analyzing atmospheric water vapor and cloud liquid water content from multi-frequency brightness temperatures.
• Estimating sea surface wind speed coincident with nadir altimeter measurements.
• Mapping global inland water bodies and ocean surface features using high-resolution radiometer data.

Strengths

• Data is from a joint NASA-CNES satellite mission launched on December 16, 2022, indicating a modern source.
• Provides measurements at three specific microwave frequencies: 18.7, 23.8, and 34 GHz.
• Distributed with a nominal latency of < 1.5 days, supporting near-real-time applications.

Limitations

• Column names and specific data structure are not provided in any source description.
• The dataset is an Interim Geophysical Data Record (IGDR) using preliminary calibrations and orbits, indicating it is not a final product.
• File size and row counts are unknown across all platforms.

Provenance

Source

Surface Water and Ocean Topography (SWOT) mission, a joint project of NASA and CNES.

Collection Method

Measurements from the Advanced Microwave Radiometer (AMR) on the SWOT satellite, processed using Medium-accuracy Orbit Ephemeris (MOE).

Time Range

Data collection began after the SWOT launch on December 16, 2022; specific end date is not provided.

Freshness

Last updated metadata date is 2026-04-09, though this may be a placeholder.

Geography

Global coverage, with measurements along satellite ground tracks over oceans and land.